Annotated bibliography of Florida basement geology and related regional and tectonic studies

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STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
Elton J. Gissendanner, Executive Director

DIVISION OF RESOURCE MANAGEMENT
Charles W. Hendry, Jr., Director

BUREAU OF GEOLOGY
Steve R. Windham, Chief

INFORMATION CIRCULAR NO. 98

ANNOTATED BIBLIOGRAPHY OF FLORIDA BASEMENT
GEOLOGY AND RELATED REGIONAL AND TECTONIC STUDIES
INCLUDING AN APPENDIX OF FLORIDA DEEP WELL DATA
By
Jacqueline M. Lloyd

Published for the
FLORIDA GEOLOGICAL SURVEY
TALLAHASSEE
1985

c^-ACE

DEPARTMENT
OF
NATURAL RESOURCES

BOB GRAHAM
Governor

GEORGE FIRESTONE
Secretary of State

BILL GUNTER
Treasurer

RALPH D. TURLINGTON
Commissioner of Education

JIM SMITH
Attorney General

GERALD A. LEWIS
Comptroller

DOYLE CONNER
Commissioner of Agriculture

ELTON J. GISSENDANNER
Executive Director

LETTER OF TRANSMITTAL

BUREAU OF GEOLOGY
TALLAHASSEE
April 15, 1985

Governor Bob Graham, Chairman
Florida Department of Natural Resources
Tallahassee, Florida 32301
Dear Governor Graham:
The Bureau of Geology, Division of Resource Management, Department
of Natural Resources, is publishing as its Information Circular No. 98,
"Annotated Bibliography of Florida Basement Geology and Related
Regional and Tectonic Studies."
This report summarizes published data on Florida basement geology and
includes an appendix of deep well data. As such, it is a comprehensive
reference publication for scientists studying Florida's deep geologic strata.
Respectfully yours,

Steve R. Windham, Chief
Bureau of Geology

Printed for the
Florida Department of Natural Resources
Division of Resource Management
Bureau of Geology

Tallahassee
1985

CONTENTS

Abstract ............................................... ............................................... VI
Introduction .................................................................... 1
Florida Basem ent Studies........................................ ...................... 2
Related Regional and Tectonic Studies................................................ 19
References....... .................................................... .......................... 39
Author Index...... ............................................................................... 41
Subject Index..................................................................................... 43
Appendix-Florida Deep W ell Data....................................................49

ABSTRACT

Annotated bibliographies of Florida basement geology and related
regional and tectonic studies are presented along with an appendix
containing Florida deep well data.
The bibliography of Florida basement geology is a comprehensive
reference list. It includes published descriptions of some of the first deep
wells drilled in Florida (e.g. Campbell, 1939 and 1940; Cole, 1944) as well
as recent tectonic interpretations of the Florida basement. Other topics
include the stratigraphy, geochronology, paleontology, and geophysical
signature of Florida basement rocks.
The bibliography of related regional and tectonic studies includes
papers on the Caribbean, Bahamas, Gulf of Mexico and West Africa. This
section is not a complete reference list on these subjects. It is provided as a
source for background information for the geologist working on the Florida
basement.
Well cutting and core information is summarized in the appendix.
These cutting and core samples are the basis for interpretation of Florida
basement geology. References for published information on these samples
are given; the samples themselves are available for further examination at
the Florida Bureau of Geology.

ANNOTATED BIBLIOGRAPHY OF FLORIDA BASEMENT
GEOLOGY AND RELATED REGIONAL
AND TECTONIC STUDIES

by
Jacqueline M. Lloyd

INTRODUCTION
This annotated bibliography is in two sections: one includes Florida
basement studies, the other includes related regional and tectonic studies.
Florida basement is generally thought of as including only pre-Mesozoic
rocks. However, more specific, and potentially more useful, definitions are
found in the cited literature. A consensus defines Florida basement as
including igneous and metamorphic rocks of Precambrian and Paleozoic
age, sedimentary rocks (primarily red beds) with associated intrusives and
extrusives of Jurassic and Triassic (?) age, and unmetamorphosed
sedimentary rocks of Paleozoic age. Although some of the authors may
define basement differently,'each paper in the Florida basement section
seems to fit somewhere within this definition. The papers in this section
include studies of the petrography, lithology, stratigraphy, geochronology,
and paleontology of Florida basement rocks. It also includes papers on the
geophysical signature and geotectonic history of the Florida basement.
The second section of the bibliography includes papers covering the
regional geology and tectonic history of the Caribbean, Bahamas, Gulf of
Mexico, and West Africa. Some of these papers do not directly discuss the
Florida basement. They are included because they provide information
pertinent to Florida basement geology. Examples are Anderson and
Schmidt (1983) and Dillon and Sougy (1974). Anderson and Schmidt
(1983) present a model for the evolution of the Gulf of Mexico-Caribbean
region. Florida's present and probable Paleozoic position tie it to such
models. Dillon and Sougy's (1974) paper is a detailed reference on West
African geology and geologic history from Paleozoic to present. It provides
information that can be useful in reconstructing the Paleozoic position of
Florida.
The appendix contains tabulated data on Florida deep wells which
penetrated basement rocks. The data includes location, total depth, depth
to basement, type of basement rocks, and references containing
information on the particular basement rocks. Other pertinent data, such as
age determinations, are listed if available. Well location maps are available
from the Florida Geological Survey.

BUREAU OF GEOLOGY

FLORIDA BASEMENT STUDIES
ANDRESS, NOEL E., FRITZ H. CRAMER, and ROBERT F. GOLDSTEIN,
1969, Ordovician chitinozoans from Florida well samples: Gulf Coast
Association of Geological Societies Transactions, vol. 19, pp. 369-375.
Ordovician chitinozoans recovered from a grayish black shale are
described for the first time for subsurface north-central Florida. The
bottom-most sample of Sun Oil Company, Earl Odom No. 1 well, Suwannee
County, Florida, was bracketed as Late Arenigian to Early Caradocian. The
Ordovician is immediately overlain by Silurian sediments. A new
chitinozoan species is described. (authors' abstract)

APPLEGATE, ALBERT V., GEORGE O. WINSTON, AND JAMES G.
PALACAS, 1981, Subdivision and regional stratigraphy of the Pre-Punta
Gorda rocks (Lowermost Cretaceous-Jurassic?) in South Florida:
Supplement to Transactions-Gulf Coast Association of Geological
Societies, vol. 31, pp. 447-453.
In recent years several wells have been drilled in the South Florida
Basin through carbonate and evaporite sequences to depths as much as
5,300 feet below the Punta Gorda Anhydrite, Correlation of anhydrite beds
below the Punta Gorda has revealed several thick anhydrite units (200 to
400 ft.) with regional persistence.
The pre-Punta Gorda section is subdivided into four easily identifiable
units listed in order of increasing age-Lehigh Acres lowermostt
Comanchean), Pumpkin Bay (upper Coahuilan), Bone Island (lower
Coahuilan), and Wood River (Jurassic?) formations, all newly named in this
report. In addition, the Lehigh Acres is divided into the West Felda Shale
(base), Twelve Mile, and Able members which are also named and defined
in this report. Geochemical evidence indicates that the Lehigh Acres unit
and the upper part of the Pumpkin Bay unit contain the most likely source
beds for petroleum.
Only two production tests have been carried out in the basin in strata
below the oil-productive Sunniland Limestone. One was through casing in a
Wood River dolomite zone. It reportedly produced water and some gas. The
other was a drill stem test in an upper Pumpkin Bay dolomite zone which
produced only water. In the Gulf Florida State Lease 826Y (Permit No. 275),
a moderately porous, 350-feet-thick Pumpkin Bay dolomite zone was
observed. As this well is west of the axis of the basin, better reservior
conditions presumably exist on the West Florida shelf than onshore.
(authors' abstract)

APPLIN, PAUL L., 1951, Preliminary report on buried pre-Mesozoic rocks
in Florida and adjacent states: U.S. Geological Survey Circular No. 91, 28
p.
This paper is a basic reference work on the subsurface pre-Mesozoic
rocks in Florida and adjacent portions of Alabama and Georgia. Available
drill hole data is tabulated for 100 deep wells: 78 wells that penetrated

INFORMATION CIRCULAR NO. 98

Paleozoic sedimentary rocks, 18 wells that encountered Triassic (?)
diabase and basalt (8 of these are included in the 78 that reach Paleozoic
sedimentary rocks), and 12 significant deep wells that did not penetrate
pre-Mesozoic rocks. These data are used to geographically divide the
pre-Mesozoic subsurface into areas characterized by (1) Paleozoic
sedimentary rocks, (2) extrusive igneous rocks (rhyolite, tuff, and
agglomerate), and (3) intrusive igenous rocks (granite, diorite) and
metamorphic rocks.
APPLIN, PAUL L., and ESTHER R. APPLIN, 1965, The Comanche Series
and associated rocks in the subsurface in central and south Florida: U.S.
Geological Survey Professional Paper 447, 86 p.
This paper is primarily a discussion of the Coastal Plain Mesozoic
sedimentary section in Florida, however, some information on pre-Meso-
zoic rocks is included. The Coastal Plain floor in central and northern
Florida is a truncated surface composed of igneous and sedimentary rocks.
These rocks are tentatively classified as primarily early Paleozoic and
Precambrian although some may be Triassic in age. The effect of the
pre-Coastal Plain structure and topography on the major and minor
structural features of the Comanche Series is discussed.
ARDEN, DANIEL D., JR., 1974, Geology of the Suwannee Basin
interpreted from geophysical profiles: Gulf Coast Association of Geological
Societies Transactions, vol. 24, pp. 223-230.
Deep drilling in the eastern Gulf Coast has penetrated the Tertiary and
Mesozoic section, but wells have seldom extended very deeply into
pre-Mesozoic rocks. Data relating to the deeper pre-Mesozoic section were
collected when Geophysical Service, Inc., conducted a seismic reflection
survey in the Suwannee Basin (also called the Apalachicola Embayment or
the Southwest Georgia Embayment). Associated gravity and magnetic field
measurements were taken. The seismic sections provided the framework
for initial geologic interpretation. Drilling data established stratigraphic
control for the upper part of the sections and verified interval velocity
determinations. A computer program generated gravity and magnetic fields
for each hypothetical geologic interpretation. These were compared with
the observed fields and refinements were made until data were reconciled.
The final interpretation shows Tertiary and Cretaceous sediments lying
above a remarkably smooth unconformity developed upon Paleozoic and
Triassic rocks. The unconformity dips southward from a depth of 8,400 feet
near the Alabama-Florida boundary to about 12,000 feet near Panama City,
Florida. Below the unconformity is a folded and faulted sequence of Lower
Paleozic rocks and Triassic continental red beds accompanied by volcanic
flows or intrusives. Paleozoic rock types include volcanics, quartzite, and a
sandstone-shale sequence. Individual structures suggest broad anticlines
developed above thrust faults. The Paleozoic rocks are tentatively
correlated with (oil-producing) African counterparts, and it is suggested that
their hydrocarbon potential warrants further investigation. (from authors'
abstract)

BUREAU OF GEOLOGY

BANKS, J. E., 1978, Southern Florida-subsurface features related to oil
exploration: Gulf Coast Association of Geological Societies Transactions,
vol. 28, part 1, pp. 25-30.
Along one trend in southern Florida, 12 oil fields have been found, with
an estimated 250 million stock-tank barrels of oil-in-place. Continued
discovery of oil and gas in new fields and along new trends may be partly
insured by structural mapping of the three types of basement rocks under
peninsular Florida; by testing the first porosity in Paleozoic basement; by
projecting the structural influence of basement troughs, paleovalleys,
ridges and hills into overlying sediments; by distinguishing between two
interfingering sedimentary platforms above basement-a northern one
deposited on a convex floor, and a thicker, somewhat lower southern one
overlying a flat-to-concave floor. (from authors' abstract)

BARNETT, RICHARD S., 1975, Basement structure of Florida and its
tectonic implications: Gulf Coast Association of Geological Societies
Transactions, vol. 25, pp. 122-142.
Geologic data from nearly 80 recent wells (1965 through 1975) in
Florida and Georgia permit substantial refinement of earlier interpretations
of Florida basement structure.
Upper Jurassic, Cretaceous, and Tertiary sediments in Florida onlap
the eroded surface of a basement complex which varies from Precambrian
to Jurassic in age. As determined by previous workers, the main structural
feature underlying Florida is the Peninsular Arch. This is a large
Precambrian block covered by Paleozoic sediments. A similar, smaller
crustal block (the Decatur Arch or Chattahoochee Anticline), centering on
Jackson County, occupies the Florida panhandle. In both blocks,
Ordovician to Devonian plastic rocks overlie a deeply truncated Precam-
brian complex which was affected by Cambrian igneous intrusion. The
Paleozoic rocks were subjected to Late Paleozoic uplift with some volcanic
activity followed by uplift with tilting, block faulting and post-orogenic
igneous intrusion during the Triassic period. The new data presented here
clarify the succession and areal distribution of some of the volcanic and
hypabyssal rocks, showing that Jurassic basalt flows covered the
Peninsular Arch below the 280N parallel.
The entire Florida portion of the Florida-Bahama platform probably
represents crust which has been continental throughout Phanerozoic time.
Subsurface data from Florida do not support the more speculative
hypotheses about the history of the Florida-Bahama Platform and the Gulf
of Mexico region. Published and new geologic data are consistent with
responsible attempts to reconstruct the history of the Gulf of Mexico region
by drifting during the opening of the North Atlantic Ocean basin. This
agreement so far represents circumstantial evidence (general resem-
blance between early Paleozoic and Precambrian of Florida and west
Africa) for the operation of plate tectonic mechanisms rather than direct,
conclusive proof. The evidence, such as it is, favors the hypothesis outlined
by Freeland and Dietz (1972). The circumstantial nature of evidence for the

INFORMATION CIRCULAR NO. 98

former activity of plate tectonic mechanisms in Florida need not hinder the
application of new tectonic theories to petroleum exploration in Mesozoic
rocks of the Florida-Bahama region and the outer continental shelf of the
Atlantic coast. (authors' abstract; parenthetical comments added)

BASS, MANUEL N., 1969, Petrography and ages of crystalline rocks of
Florida-some extrapolations: American Association of Petroleum Geolo-
gists Memoir No. 11, pp. 283-310.
The most widespread of the crystalline basement rocks of Florida are
rhyolitic ignimbrites. Regional metamorphism has not affected the
ignimbrites, and where greenschist-facies rocks are found the metamor-
phism is incomplete and local in extent. The age of the ignimbrites is
unknown. Arguments are presented for Precambrian, late Paleozoic,
Triassic, or Jurassic ages.
Intrusive rocks in Florida and Georgia are distributed sporadically
except in an area of central Florida where a granitic province can be
outlined. Granitic rocks are generally altered. In one well (Humble No. 1
Carroll, Sec. 10, T27S, R34E, Osceola County, P-8, W-1014), the quartz
monzonite is cataclastically shattered and veined but not pervasively
sheared. Another well (Sun No. 1, Powell Land Company, Sec. 11, T17S,
R31E, Volusia County, P-19, W-1118) encountered a quartz-bearing
hornblende diorite sill. This diorite is at least 480 m.y. old.
A province of mafic extrusive rocks is proposed for southern or
southwestern Florida. The basalt resembles submarine basalt and may be
related to buried seamounts. The basalt may be much younger than the
acidic volcanic rocks.
The southeastern-most well (the Amerada No. 2, Cowles Magazines,
Inc., Sec. 19, T36S, R40E, St. Lucie County, P-259, W-4323) penetrated
diabase overlying, and in apparent fault contact with, regional metamorphic
rocks. These rocks are mainly quartz-bearing hornblende-andesine
amphibolite containing layers of leucocratic quartz diorite gneiss. This
amphibolite is 530 m.y. old, or older. It is probably in a branch of the
Damaran (or Pan-African) orogen. Meager data suggest that the diabase in
this well may be of late Paleozoic, Triassic, or Jurassic age.
The age results for the various rock types indicate that an event about
530 million years ago resulted in amphibolite-facies and retrograde
zeolite-facies metamorphism of mafic or intermediate igneous rocks in
southern Florida. This event was probably accompanied by either
metamorphism or emplacement of the quartz monzonite of the Carroll well
and emplacement of the diorite of the Powell well. The country rocks
intruded by the diorite were either Precambrian metamorphic rocks or
sediments derived, at least partly, from Precambrian rocks.

BRIDGE, JOSIAH, and JEAN M. BERDAN, 1951, Preliminary correlation of
the Paleozoic rocks from test wells in Florida and adjacent parts of Georgia
and Alabama: U.S. Geological Survey Open File Report, 8 p., also in

BUREAU OF GEOLOGY

Florida Geological Survey Guidebook, Association American State
Geologists 44th Annual Meeting Field Trip, April 1952, pp. 29-38.
Reported results are based on a preliminary study of cores, cuttings,
and fossils from 52 test wells in central and northern Florida and adjacent
parts of Georgia and Alabama. The subsurface Paleozoic rocks in this
region include strata ranging from Early Ordovician to Early or possibly
Middle Devonian. The area underlain by Paleozoic rocks can be roughly
outlined by a triangle with sides approximately 250-miles long. It is bounded
to the north and southeast by areas underlain by crystalline and volcanic
rocks.
The Paleozoic strata are flat-lying, unmetamorphosed clastics, and
were apparently deposited in shallow water. The source of the sediments is
unknown. The total thickness of Paleozoic sediments is estimated to be not
less than 3,000 feet and probably equal to 6,000 feet or more.
The distribution of Paleozoic rocks of different ages indicates the
possibility that the wedge of Paleozoic rocks is made up of a series of
subparallel belts, each with a general northeast trend, and each separated
from adjacent belts by faults. The age of faulting is post-Middle(?) Devonian
to pre-Early Cretaceous. Igneous intrusions cutting the Paleozoic
sedimentary rocks fall within the same age limits.

CAMPBELL, R. B., 1939, Paleozoic under Florida?: American Association
of Petroleum Geologists Bulletin 23, No. 11, pp. 1712-1713.
A brief report on the black shales found in the St. Mary's River
Corporation Hilliard Turpentine Co. No. 1 well in Nassau County, Florida, is
presented in this paper. The black shales are tentatively assigned a
Mississippian age because of their similarity to the Chattanooga shales.

CAMPBELL, R. B. 1940, Outline of the geological history of peninsular
Florida: Florida Academy of Science Proceedings, 1939, vol. 4, pp. 87-105.
Previously unpublished data on eight Florida wells is presented.
Paleogeographic changes (Cretaceous through Recent) of the Florida
peninsula are depicted. The influence of the three "ancient nuclear land
masses"-Appalachia, Llanoria, and Antillia-and the coverage by sea
waters are discussed. The conclusion is that the "Florida peninsular area
throughout most of its geologic history has been submerged and as such,
has been the connecting link from the Gulf of Mexico to the Atlantic,
between the nuclear land masses of Appalachia and Antillia, roughly
represented today by the Piedmont area of the southern states and the
Greater Antilles respectively."

CARROLL, DOROTHY, 1963, Petrography of some sandstones and
shales of Paleozoic age from borings in Florida: U.S. Geological Survey
Professional Paper 454-A, 15 p.
Sandstone, orthoquartzites, other arenaceous sediments and black
and red shales occur in the basement rocks of Florida and adjacent parts of

INFORMATION CIRCULAR NO. 98

Georgia and Alabama. Most of the sandstones are Early Ordovician in age.
The shales range in age from Middle Ordovician to Middle Devonian.
The quartzites range in mineralogic complexity from submature to
mature. Feldspars are scarce. Micaceous and clayey sandstones can be
classed as subgraywackes. Many of the quartzites grade into siltstones that
are intercalated with shaly and micaceous layers. Such beds show
disturbed bedding and penetration by worm borings. These beds may be of
shallow-water marine origin.
All the arenaceous sediments contain small amounts of heavy
minerals. Three characteristic heavy-mineral assemblages were recog-
nized that could be used to correlate different beds in the sequence. The
minerals indicate sources in granitic and metamorphic rocks, although
rounding of the grains suggests that most of the rocks were derived finally
from second- or third-cycle sediments.
The black shales contain abundant organic matter, pyrite, and
commonly, interlaminations of siderite and calcite. The color of the red
shales is due to minute blebs of hematite in the micaceous matrix. (from
author's abstract and summary)

CHOWNS, T. M., and C. T. WILLIAMS, 1983, Pre-Cetaceous rocks
beneath the Georgia Coastal Plain-regional implications: in Gohn,
Gregory S. (editor), Studies related to the Charleston, South Carolina,
earthquake of 1886-tectonics and seismicity: U.S. Geological Survey
Professional Paper 1313-L, 42 p.
The records of 78 wells that have penetrated pre-Upper Jurassic(?)
rocks beneath the Georgia Coastal Plan were analyzed and used as the
basis for a regional interpretation of the "basement" of the southeastern
U.S. Coastal Plain. These results were compared with the results of similar
studies in Florida, Alabama, and South Carolina. With the addition of
regional aeromagnetic data, regional interpretations were made.
Felsic volcanic and associated rocks found in the Georgia subsurface
are identical to those found beneath the Apalachicola embayment in
Alabama and the Florida panhandle, on the southeast flank of the
Peninsular Arch in central Florida, and in south Florida. Evidence suggests
that, aside from those found in south Florida, the volcanic rocks are
Proterozoic Z (Late Proterozoic) or early Paleozoic in age. Available data
indicate a Mesozoic age for the south Florida rocks. The Proterozoic to
Paleozoic volcanic rocks probably represent a disjunct fragment of the
African craton, sutured to North America during the late Paleozoic. The
position of the suture is unknown, but the boundary between the Piedmont
rocks of the Appalachian orogen and African platform rocks may be traced
in the subsurface east-northeast from Alabama to South Carolina. Before
the opening of the Atlantic, this boundary was continuous with the
overthrust on the east side of the African Mauritanide orogenic belt.
The most extensive terrane beneath the Southeastern Coastal Plain is
a broad basin (the South Georia Basin) filled with red beds, associated
diabase intrusions, and possibly basalt. These red beds occupy an

BUREAU OF GEOLOGY

estimated 50,000-65,000 sq. km in Georgia and a similar area in adjacent
parts of Florida, Alabama, and South Carolina. The diabase and basalt are
Early Jurassic in age; the red beds are Late Triassic(?) to Early Jurassic(?).
For simplicity, the red beds are referred to as Triassic. Much of this Triassic
terrane has undergone zeolite-facies alteration. The alteration is most
pronounced, but not restricted to, contact aureoles of the diabase bodies.
The Triassic terrane probably represents a complex graben structure,
formed during the early stages of the opening of the North Atlantic (215-175
million years ago). The southeastern corner of North America was close to
the triple junction between the North Atlantic, South Atlantic and the Gulf of
Mexico, therefore, complex rifting and transform faulting would be
expected. The position and size of the South Georgia basin, as well as the
large volume of mafic igneous rock and evidence of high heat flow, suggest
that during the Late Triassic and Early Jurassic, incipient spreading centers
in the Gulf of Mexico and the North Atlantic may have been linked beneath
this basin.
The Brunswick magnetic anomaly, which swings through South
Georgia, is probably of late Paleozoic origin. It may be caused by a thick
section of African-plate rocks, which was formed by overthrusting during
continental collision. This similarity in trend between the early Mesozoic
East Coast anomaly at the margin of the Carolina shelf and the Brunswick
anomaly suggests that the position of the Atlantic spreading center may
have been influenced by this Paleozoic structure. (partially extracted from
authors' abstract)

COLE, W. STORRS, 1944, Stratigraphic and paleontologic studies of
wells in Florida-No. 3: Florida Geological Survey Bulletin No. 26, 168 p.
This document includes a detailed stratigraphic and paleontologic
description of the St. Mary's Oil Corporation, Hilliard Turpentine Company
No. 1 well, Sec. 19, T4N, R24E, Nassau County (W-336, no permit
number). The well was completed in 1940 at a depth of 4,817 feet. The well
encountered a black shale at 4,640 to 4,795 feet and a diabase sill or dike at
4,795 to 4,817 feet. The black shale and the diabase are both believed to be
Triassic in age, although the age of the shale has been the subject of much
debate.

CRAMER, FRITZ H., 1971, Position of the North Florida Lower Paleozoic
block in Silurian time; phytoplankton evidence: Journal of Geophysical
Research, vol. 76, no. 20, pp. 4754-4757.
The Silurian reconstruction of Pangea leaves a space inside the
divergence of the 1,000-fathom contours of the African and South American
continental blocks. Palynological evidence suggest this space as a
pre-Late Devonian location for the North Florida Lower Paleozoic block. It
was brought to its present position with respect to the Appalachians when
the proto-Atlantic closed in the Late Devonian.

CRAMER, FRITZ H., 1973, Middle and Upper Silurian chitinozoan

INFORMATION CIRCULAR NO. 98

succession in Florida subsurface: Journal of Paleontology, vol. 47, no. 2, pp.
279-288.
Unmetamorphosed Paleozoic rocks are present in the subsurface of
Florida. Silurian acritarchs, chitinozoans and miospores have been
recovered from black to gray shales of four wells in the north-central portion
of the state. On account of its palynomorphs, mainly chitinozoans, this
material is dated as very latest upper Llandoverian though upper Ludlovian
or very basal Gedinnian. The Florida ranges of 28 stratigraphically valuable
chitinozoan taxa are plotted; nearly all taxa are illustrated by photomicro-
graphs.
The Florida palynomorph spectra and their chronological succession
are quite similar to age-equivalent material from Portuguese Guinea and, in
part, to material from North Africa.
The palynological data suggest that the environment of deposition in
north-central Florida was holomarine, and not lagoonal as was supposed
before. (author's abstract)

GOLDSTEIN, ROBERT F., FRITZ H. CRAMER, and NOEL E. ANDRESS,
1969, Silurian chitinozoans from Florida well samples: Gulf Coast
Association of Geological Societies Transactions, vol. 19, pp. 377-384.
Chitinozoans of Silurian age were recovered from four wells in north
peninsular Florida: Humble-Cone No. 1 (Sec. 22, TIN, R17E, P-77,
W-1789); Sun Oil-Tillis No. 1 (Sec. 28, T2S, R15E, P-57, W-1548); St.
Mary's River-Hilliard No. 1 (Sec. 19, T4N, R24E, no permit number,
W-336); and Gulf-Kie Vining No. 1 (Sec. 2, T4S, R15E, P-124, W-2164). An
attempt was made to establish a correlation between these four wells using
the chitinozoan evidence. The youngest assemblage encountered is
probably Ludlovian in age; the oldest is of late Llandoverian age. (from
authors' abstract)

GRASTY, R. L., and J. TUZO WILSON, 1967, Ages of Florida volcanics
and of opening of the Atlantic Ocean: Tectonophysics Abstracts, American
Geophysical Union Transactions, vol. 48, pp. 212-213.
Four basalts from Florida deep wells were obtained and dated. Ages
ranged from 140 to 180 million years; the older age is believed to be more
correct. It agrees with similar ages reported for basic intrusives along the
coast. It is also compatible with the view that the North Atlantic Ocean
began opening at that time and that the Florida-Bahamas ridge may have
formed along the boundary with the pre-existing Gulf of Mexico. (from
authors' abstract)

GRIFFIN, GEORGE M., DAVID A. REEL, and RICHARD W. PRATT, 1977,
Heat flow in Florida oil test holes and indications of oceanic crust beneath
the southern Florida-Bahamas platform: in Smith, Douglas L., and George
M. Griffin (editors), The geothermal nature of the Florida Plateau: Florida
Bureau of Geology Special Publication 21, pp. 43-64.
Heat flow values were obtained for three deep oil-test holes. Two test

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holes in southern Florida yielded values of 0.71 and 0.76 HFU*, one in
northern Florida yielded a value of 0.92 HFU. This trend on land parallels a
similar trend offshore and is approximately the same in magnitude. The low
values for southern Florida support the hypothesis that oceanic crust (low
heat generating capacity) underlies the southern part of the Florida-Baha-
mas platform.
"Note: 1 HFU (or heat flow unit) = 1 x 10-6 cal/cm2 sec. The average heat
flow from continental areas is about 1.5 HFU.

KING, ELIZABETH R., 1959, Regional magnetic map of Florida: American
Association of Petroleum Geologists Bulletin, vol. 43, pp. 2844-2854.
A regional magnetic map of Florida reflects the structural trends of the
magnetically heterogeneous Paleozoic and Precambrian rocks underlying
the coastal plain rocks. Many trends and features on the magnetic map
have gravity counterparts, indicating a common source. On the basis of the
regional magnetic trends, Florida is divided into two tectonic provinces with
an intervening zone of intrusive rocks. Depth estimates from aeromagnetic
data suggest the possibility that faulting may be a factor in the profound
downwarping and accumulation of sediments in the southern province. The
trends of the northern province parallel those of the Appalachian system to
which they are probably related. The southern province, distinguished by
northwest trends, is structurally discordant with the northern province. The
magnetic evidence suggest that the southern province is a continuation of
the Ouachita system which has been traced beneath the Gulf Coastal Plain
to within 60 miles of the subsurface extension of the Appalachian system in
Mississippi, where the two systems approach each other at nearly a right
angle. (author's abstract)

KLITGORD, KIM D., PETER POPENOE, and HANS SCHOUTEN, 1984,
Florida: a Jurassic transform plate boundary: Journal of Geophysical
Research, vol. 89, no. B9, pp. 7753-7772.
Magnetic, gravity, seismic, and deep drill-hole data integrated with
plate tectonic reconstructions substantiate the existence of a transform
plate boundary across southern Florida during the Jurassic. On the basis of
this integrated suite of data the pre-Cretaceous Florida-Bahamas region
can be divided into the pre-Jurassic North American plate, Jurassic
marginal rift basins, and a broad Jurassic transform zone including
stranded blocks of pre-Mesozoic continental crust. Major tectonic units
include the Suwannee basin in northern Florida containing Paleozoic
sedimentary rocks, a central Florida basement complex of Paleozoic age
crystalline rock, the west Florida platform composed of stranded blocks of
continental crust, the south Georgia rift containing Triassic sedimentary
rocks which overlie block-faulted Suwannee basin sedimentary rocks, the
Late Triassic-Jurassic age Apalachicola rift basin, and the Jurassic age
south Florida, Bahamas, and Blake Plateau marginal rift basins. The major
tectonic units are bounded by basement hinge zones and fracture zones
(FZ). The basement hinge zone represents the block-faulted edge of the

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North American plate, separating Paleozoic and older crustal rocks from
Jurassic rifted crust beneath the marginal basins. Fracture zones separate
Mesozoic marginal sedimentary basins and include the Blake Spur FZ,
Jacksonville FZ, Bahamas FZ, and Cuba FZ, bounding the Blake Plateau,
Bahamas, South Florida and southeastern Gulf of Mexico Basins. The
Bahamas FZ is the most important of all these features because its
northwest extension coincides with the Gulf basin marginal fault zone,
forming the southern edge of the North American plate during the Jurassic.
The limited space between the North American and the South American/
African plates requires that the Jurassic transform zone, connecting
between the Central Atlantic and the Gulf of Mexico spreading systems,
was located between the Bahamas and Cuba FZ's in the region of southern
Florida. Our plate reconstructions combined with chronostratigraphic and
lithostratigraphic information for the Gulf of Mexico, southern Florida, and
the Bahamas indicate that the Gulf was sealed off from the Atlantic waters
until Callovian time by an elevated Florida-Bahamas region. Restricted
influx of waters started in Callovian as a plate reorganization, and increased
plate separation between North America and South America/Africa
produced waterways in the Gulf of Mexico from the Pacific and possibly
from the Atlantic. (authors' abstract)

KRIVOY, HAROLD L., and THOMAS B. PYLE, 1972, Anomalous crust
beneath West Florida Shelf: American Association of Petroleum Geologists
Bulletin, vol. 56, no. 1, pp. 107-113.
A new Bouguer gravity anomaly map of the west Florida continental
margin reveals a landward salient of high positive values in the vicinity of St.
Petersburg. A 20,000 sq km area of the shelf characterized by anomalies
greater than +30 mgal is thought to be underlain by a crust having a
thickness intermediate between that of continents and that of oceans. A
transition from oceanic toward continental crust in this area may have been
accomplished by reef progradation across an ancient oceanic embayment.
Alternatively, a transition from continental toward oceanic crust may have
been produced by rotation of Florida and consequent rifting. The
reef-progradation hypothesis is most consistent with what is known of the
deep structure and tectonic setting of the Florida platform. (authors'
abstract)

MILTON, CHARLES, 1972, Igneous and metamorphic basement rocks of
Florida: Florida Bureau of Geology Bulletin 55, 125 p.
This report describes in detail all the cores and cuttings available from
a large collection of wells which were drilled in the Florida Coastal Plain,
which penetrated rocks older than the Late Cretaceous, Tuscaloosa
Formation. The petrography of basement rock from 27 Florida wells is
described; also some 14 isotopic dating from six wells in Florida and three
in Georgia, and chemical analyses of rocks from seven Florida wells are
given.
Although many wells have been drilled into the Florida pre-Cretaceous

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spathic sandstone and shale. A similar sequence of rocks is observed in
Guinea, 200 km northeast of the west African shoreline; there the rocks,
also sandstones and shales, are of the same age, Ordoviclan-Devonlan.
Similarly, they unconformably overlie a deformed and metamorphosed
basement of pre-Cambrian and Cambrian age. These similarities between
the Florida and Guinea terranes ... suggest their correlation and
consequently, their relevance to pre-Atlantic reconstructions.
In the reconstruction of LePichon and others (1977) the two terranes
are separated by several hundred kilometers. A more northerly position of
Africa-South America with respect to North America results in a closer
correspondence of the two terranes. Since the reconstruction of LePichon
and others (1977) and the subsequent seafloor spreading history are well
justified from marine data, the more northerly position of Africa was
probably achieved in the latest Paleozoic or early Mesozoic, prior to
opening of the present-day Atlantic Ocean. (author's abstract)

POJETA, JOHN, JR., JIRI KRIZ, and JEAN M. BERDAN, 1976,
Silurian-Devonian pelcypods and Paleozoic stratigraphy of subsurface
rocks in Florida and Georgia and related Silurian pelecypods from Bolivia
and Turkey: U.S. Geological Survey Professional Paper 879, 32 p.
The subsurface sedimentary Paleozoic rocks beneath northern Florida
and adjacent parts of Georgia and Alabama comprise a sequence of
quartzitic sandstones and micaceous shales, dark-gray shales, and red
and gray siltstones ranging in age from Early Ordovician to Middle
Devonian. The Silurian-Devonian pelecypod faunas from four wells (three
of which, the Ragland, Cone, and Tillis wells, are in Florida, and one of
which, the Chandler, is in Georgia) are described and illustrated. Also
described are Silurian pelecypods from one locality in Bolivia and one in
Turkey.
Biostratigraphically, the faunas from the American wells range in age
from Wenlockian or Ludlovian (Silurian) to Middle Devonian; the Bolivian
specimens are probably Ludlovian (Late Silurian); and the Turkish
specimens are probably Wenlocklan or Ludlovian (Silurian). Paleocologi-
cally, the strata in the American wells represent shallow-water normal
marine environments, and all pelecypods known from them belong to one of
three life-habit groups-byssally attached, burrowing, or reclining. The
Bolivian and Turkish pelecypods likewise belong only to these three
life-habit groups. Analysis of the geographic distribution of the Florida
Paleozoic pelecyod genera shows that they are closest to the forms found
in central Bohemia and Poland; elements of this fauna also occur in Nova
Scotia, North Africa, and South America. (authors' abstract)

SHERIDAN, ROBERT E., J. T. CROSBY, G. M. BRYAN, and P. L.
STOFFA, 1981, Stratigraphy and structure of Blake Plateau, northern
Florida Straits, and northern Bahama Platform from multichannel seismic
reflection data: American Association of Petroleum Geologists Bulletin, vol.
65, pp. 2571-2593.

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Approximately 2,100 km of 24-fold multichannel seismic reflection data
reveal much about the subsurface geology for a large part of the continental
margin east of Florida. Discordance between the westward-dipping
pre-breakup sediments and the eastward-sloping basement along the edge
of the Blake Plateau is interpreted as an effect of a splinter of continental
margin derived from the African plate by a spreading-center jump in the
Middle Jurassic. Early rifting centered under the main part of the Blake
Plateau became inactive, as a spreading-center jump shifted the active rift
to east of the present Blake Escarpment along the Blake Spur magnetic
anomaly.
In the northern Florida Straits -the data reveal that the breakup
unconformity, underlain by Triassic-Lower Jurassic(?) arkosic volcaniclas-
tics, extends from southern Florida to the western Bahama Banks. These
volcaniclastics are associated with the rift-crust of intermediate nature
formed just prior to and during breakup of the North American and African
continental plates.
Back-reef platform deposits of limestones, dolomites, and evaporites
of Late Jurassic to Albian age extend from the Blake-Bahamas Escarpment
westward beneath Florida. These deposits formed what once was a
megabank extending over a wider area than the present smaller isolated
Bahamas Banks. The formation of the Florida Straits and Bahamas
channels occurred during the Cenomanian transgression. Only on the
present Bahamas Banks and Florida platform did shallow-water carbonate
deposition persist to maintain a shallow-bank environment.
Evidence of recurring scour by current erosion is found in the Florida
Straits. Erosional events apparently occurred in the middle Cenomanian,
middle Paleocene, early-middle Eocene, and Eocene-Oligocene, which
coincidentally are times of lower eustatic sea level according to Vail et al.
(1977). This evidence of Florida current scour indicates that the current was
present as far back as the Cenomanian.
Major faulting appears to have dropped the Northeast Providence
Channel relative to the western Bahamas after the Albian. Submarine
erosion and bank buildup created the channels and smaller relief features
like Great Abaco Knoll beginning in about the Cenomanian.
A carbonate bank margin and reef complex was present along the
Bahamas Escarpment since the Middle Jurassic. Apparently these organic
buildups seeded on originally shallow structural relief on oceanic basement
created during the spreading-center jump to the position of the Blake Spur
magnetic anomaly. The bank margin apparently has retreated at least 15
km from a Late Jurassic-earliest Cretaceous position now marked by a
bench below the Au unconformity*.
Active faulting occurred along the Great Abaco fracture zone at least
through the Late Cretaceous and perhaps into the Tertiary. These relatively
young tectonic events, together with the post-Albian faults in Providence

*Note: The A" reflector, or horizon, is a hiatus between lower Miocene and
possibly Cenomanian rocks.

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Channel, indicate interactions between the Atlantic and Caribbean plates
and that extensions of faulting have taken place far to the northeast of Cuba
and the Greater Antilles. (authors' abstract)

SHERIDAN, ROBERT E., C. L. DRAKE, J. E. NAFE, AND J. HENNION,
1966, Seismic refraction study of continental margin of Florida: American
Association of Petroleum Geologists Bulletin, vol. 50, pp. 1972-1991.
Data from 31 seismic-refraction profiles are interpreted and presented
in five structure sections. The subsurface structure east of Florida under the
Blake Plateau is similar to that of the margin north of Cape Hatteras.
Basement plunges seaward from Florida into a deep sedimentary trough
under the Blake Plateau. A basement ridge parallels this north-south-
trending trough on the seaward side, along the eastern edge of the plateau.
The basin under the Blake Plateau was separated from the South
Florida-Andros Island basin,, at least until the Early Cretaceous, by a
southeastward extension of the Peninsular Arch. This seaward extension
trends from just east of Cape Kennedy to the western end of Little Bahamas
Bank.
The marked relief of the Florida shelf, the Florida Straits, and the Blake
Plateau is evident only in the sedimentary layers and is the result of
significant changes in thickness of the post-Paleocene section, especially
the Eocene. The top of the Paleocene extends beneath the present
physiographic irregularities with slight relief, whereas the Eocene thickness
ranges from about 500 m on Florida to about 70 m on the Blake Plateau.
Strong currents sweeping the Florida Straits and Blake Plateau probably
are responsible for the absence of a thick post-Paleocene section. The
present orientation of the Florida current may have existed as early as
Paleocene time.
Besides the changes in relief within the sedimentary section, there are
lateral faces changes and velocity variations. These variations are
primarily dependent on the depth of burial. Nearly similar velocity-depth
distributions are found for the Blake Plateau, the Florida Straits, the
Bahamas Banks, and the Florida Platform. The variations in thickness of
the sediments in these areas result in variable velocities in the stratigraphic
units, and correlation of the refraction data is difficult. (authors' abstract)

SMITH, DOUGLAS M., 1983, Basement model for the panhandle of
Florida: Gulf Coast Association of Geological Societies Transactions, vol.
33, pp. 203-208.
Core samples from deep boreholes in panhandle Florida form the
basis of a basement model involving at least eight separate fault blocks and
basins, each with a distinct depositional history. The dominant structures
are a northwest-trending fault and a large northeast-trending Triassic
graben which encompasses several secondary fault blocks and forms the
Southwest Georgia Embayment (Apalachicola Embayment). This graben
as well as associated and perpendicularly-oriented (northwest-southeast)
faults were formed in response to tensional forces related to the Mesozoic

INFORMATION CIRCULAR NO. 98

separation of North American and South American land-masses and the
consequent formation of the Gulf of Mexico. Granitic basement blocks,
perhaps Early Cambrian in age, experienced differential subsidence and
changing relationships with various sedimentary source terrains. Thus, the
separate basins accomodated different combinations of Triassic Eagle
Mills red beds and Jurassic deposits ranging from the Louann Salt to the
Cotton Valley sandstones and shales. (author's abstract)

SMITH, DOUGLAS M., 1982, Review of the tectonic history of the Florida
basement: Tectonophysics, vol. 88, pp. 1-22.
This paper provides a comprehensive review of the lithological,
geochronological, paleontological, and geophysical data used to interpret
the tectonic history of Florida. Comparison with similar data on African
rocks yields a model for the tectonic history of the Florida basement. The
author's abstract summarizes the model as follows:
"Lithological similarities between the Suwannee Basin deposits of
undeformed Ordovician and Silurian sandstone and shale lying
0.9-1.9 km below the north Florida surface and equivalent-aged
strata from Senegal to Sierra Leone in western Africa suggest an
African location for the Florida basement during the early
Paleozoic. The southern edge of the Paleozoic sediments laps
onto a Pan-African granitoid batholith which is considered
representative of a nearly Paleozoic Afro-South American
assemblage. A late Paleozoic (Allegheny) continental closure
brought the Florida basement, and much of the present-day Gulf
Coastal margin, into juxtaposition with North America, but the
arrangement of continental promontories precluded a direct
application of deforming stresses to the overlying basin sedi-
ments. Numerous occurrences of early Mesozoic rhyolitic tuffs
and ignimbrites in deep (2.7-5.5 km) bore holes from central and
south Florida are interpreted as indicative of a Triassic hot spot
that initiated rifting and the opening of the North Atlantic.
Subsurface rhyolitic rocks are also present in northern Florida, but
the position of the hot spot dictated that the Florida Plateau remain
appended to North America as radially propagating rifts from the
hot spot created a new configuration of plate boundaries from
those of the Paleozoic. Other continental terrains adjacent to
southern Florida were either altered and foundered to underlie the
Bahamas or stayed with Africa and/or South America."

WALPER, JACK L., 1974, The origin of the Bahamas Platform: Gulf Coast
Association of Geological Societies Transactions, vol. 24, pp. 25-30.
The origin of the Bahama platform and its continued subsidence to
permit the accumulation of a thick carbonate cap has been a problem of
middle American geology. The relation of this feature to previously
published reconstructions of the late Paleozoic-early Mesozoic "fit" of
North America, Africa and South America has also posed a problem. A new

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model incorporating the volcano-tectonic rift and ignimbrite sheet
association is proposed to explain the origin of the Bahama platform as an
integral part of Caribbean plate tectonics. A new North America-South
America join is utilized to account for the major geologic and tectonic
continuities of Paleozoic age throughout Mexico and Central America.
The clockwise rotation of North America as it separated from South
America and Africa caused the counterclockwise bending of the entire
peninsula of Mexico and Central America, with the newly accreted
Caribbean plate into a subduction zone that was to evolve into the
arc-trench system of the Greater Antilles. The rotation and beginning of
subduction of this Caribbean plate into the Cuban trench, in Jurassic time,
triggered volcanic eruptions that provided the foundations for the Cuban
volcanic arc and the usual thick and widespread ignimbrite sheet behind the
arc in the area now occupied by peninsula Florida and the Bahama Banks.
Not only is evidence for this feature found in wells drilled in Florida but it
also provides the foundation upon which was deposited the thick sequence
of carbonate strata that forms the Bahama Banks. This interpretation
eliminates the overlap of the Bahama salient onto Africa, explains the origin
of the Old Bahama Channel, serves the same purpose as the sedimentary
prism proposed by Dietz and other (1970) and has the volcanic character to
meet the geophysical requirements indicated by Uchupi and others (1971).
(author's abstract)

WICKER, RUSSELL A., and DOUGLAS L. SMITH, 1977, Florida
basement-an isometric view: American Association of Petroleum
Geologists Bulletin, vol. 61, pp. 2143-2145.
An isometric view of the Florida basement surface, based on available
core data from more than 150 boreholes, has been derived by application of
the SYMAP and SYMVU computer programs. This visualization shows
numerous topographic features which can be associated with structural
patterns in the overlying formations and illustrates a significant contrast in
basement depth between northern and southern Florida. (authors'
abstract)

WICKER, RUSSELL A., and DOUGLAS L. SMITH, 1978, Reevaluating
the Florida basement, Gulf Coast Association of Geological Societies
Transactions, vol. 28, pp. 681-687.
A generalized representation of the basement and overlying sedimen-
tary rocks of peninsular Florida has been developed utilizing available
gravity anomaly values, deep test-well data, and a variation of the Talwani,
et al. (1959) two-dimensional gravity modeling technique. Subsurface
density and depth values along 10 profiles were adapted to an iterative
calculating process to generate gravity anomaly profiles conforming to
those observed. Modeled cross-sections along these profiles were then
used to interpolate basement and sedimentary configurations for the entire
peninsula. The final models display the low density (1.95-2.15 gm/cm3)
near-surface rocks of Late Cretaceous to Recent ages extending to depths

INFORMATION CIRCULAR NO. 98

ranging from approximately 0.8 to 2.6 km. Depths of the underlying Lower
Cretaceous rocks (density of 2.30 to 2.55 gm/cm3) extend to approximately
1.4 km in north Florida and more than 4.7 km in south Florida. An abrupt
north-to-south increase in average basement rock density from 2.73 to 3.00
gm/cm3 is evident along a general east-west trending zone passing through
the central portion of the peninsula. This supports a concept of a
north-to-south transition from continental to oceanic type rocks underlying
the thick sedimentary sequence of the central Florida peninsula. (authors'
abstract)
WILSON, GARY V., 1975, Early differential subsidence and configuration
of the northern Gulf Coast Basin in southwest Alabama and northwest
Florida: Gulf Coast Association of Geological Societies Transactions, vol.
25, pp. 196-206.
Deep test-well information in southwest Alabama and northwest
Florida indicates that early differential subsidence of the basement had a
marked influence on the thickness and distribution of accumulating coastal
plain sedimentary deposits, especially carbonates, evaporites and thick
marine shale units. Geophysical data reveal that these differential
movements were either directly or indirectly related to lateral variations in
the thickness of crustal layers. These crustal thickness variations may have
been either the cause of differential subsidence of the basement or the
result of deep-seated forces that induced or affected subsidence. Regional
gravity anomalies reflect crustal thickness variations associated with the
Wiggins uplift and the Mississippi interior salt basin. In the study area a
basement high and stratal thinning correspond to the easternmost
extension of the Wiggins uplift and a regional gravity minimum. A basement
low and stratal thickening correspond to the eastern limb of the Mississippi
interior salt basin and a regional gravity maximum.
The configuration of the basin margin during much of Late Jurassic
time was controlled by a hinge line that roughly coincided with a system of
dense intracrustal masses. These masses probably locate a zone of
structural weakness within the crust, basinward from which initial
subsidence and marine deposition took place. The basin margin and extent
of early marine deposition was also influenced by the Wiggins uplift and the
related Conecuh arch. This influence continued until Cretaceous seas
advanced beyond the northern extent of this positive feature. (authors'
abstract)

RELATED REGIONAL AND TECTONIC STUDIES
ANDERSON, THOMAS H., and VICTOR A. SCHMIDT, 1983, The
evolution of Middle America and the Gulf of Mexico-Caribbean Sea during
Mesozoic time: Geological Society of America Bulletin, vol. 94, pp.
941-966.
A plate-tectonic model for the evolution of Middle America and the Gulf
of Mexico-Caribbean Sea region is presented. The model, which is based
upon the existence of the Mojave-Sonora megashear, incorporates into the

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Triassic Pangea reconstruction three microplates between North and
South America, thus avoiding the overlap of the Bullard fit. During late
Jurassic time, as North America split away from Europe, Africa, and South
America, shear, with left-lateral sense of displacement, occurred along the
transform faults that bounded the microplates. (from authors' abstract)

BALL, M. M. and C. G. A. HARRISON, 1969, Origin of the Gulf and
Caribbean and implications regarding ocean ridge extension, migration,
and shear: Gulf Coast Association of Geological Societies Transactions,
vol. 19, p. 287-294.
The Gulf and Caribbean are a zone of north-south extension and left
lateral shear opened between the Americas as these continents moved
westward from Africa. The movements are related to ocean floor spreading
away from the mid-Atlantic ridge. In order to accommodate spreading, the
ridge itself migrates westward from Africa. Ridge migration is radial outward
from Africa and results in opening triangular sheared grabens with apexes
against Africa. A new ridge segment extends across these openings.
Spreading rates vary and the migrating and extending ridge is sheared on
fracture zones in response to these variations.
The currently popular related concepts of plate tectonics and transform
faults are inconsistent with ridge migration and shear because these
theories deny shear on fracture zones beyond ridge offsets and in the sense
indicated by the position of ridge segments. Ridge migration and shear are
a necessary complication of the spreading hypothesis. T-intersections of
ridges are explained as intersections between a spreading and migrating
ridge and a shear. The shear is only active on the side of the ridge toward
which the migration is taking place. The junction of the mid-Atlantic ridge
with the Azores-Gibraltar ridge is an example of such a feature. (authors'
abstract)

BEALL, ROBERT, 1973, Plate tectonics and the origin of the Gulf Coast
Basin: Gulf Coast Association of Geological Societies Transactions, vol.
23, pp. 109-114.
The origin of the Gulf Coast basin and many of the structures in the
basin are explained by a proposed Gulf basin miniplate. The miniplate lies
between a large right lateral megashear which extends from under'the
eastern Gulf of Mexico to the east end of the Ouachita Mountains, and a left
lateral megashear of similar proportions which parallels the Mexican
coastline and extends to the Marathon uplift. The Llano uplift acted as a
buttress against northwestward movement of the Gulf basin plate.
The plate is believed to have moved more than 400 miles to the
northwest during a Precambrian-Paleozoic compression cycle. When
compression ceased, at or near the end of the Paleozoic Era, the Mesozoic
Gulf Coast basin was formed over the slowly tilting plate. Rebound,
associated with the cessation of compression, caused tension faults to form
along old zones of crustal weakness. The graben and other fault trends in
and adjacent to the interior salt basins are believed to overlie these crustal

INFORMATION CIRCULAR NO. 98

faults as are some of the similar structural features of the coastal basin.
(from author's abstract)
BEHRENDT, JOHN C., JOHN SCHLEE, JAMES M. ROBB, and
KATHERINE M. SILVERSTEIN, 1974, Structure of the continental margin
of Liberia, West Africa: Geological Society of America Bulletin, vol. 85, pp.
1143-1158.
Geophysical surveys made by RN Unitedgeo I (USGS-IDOE Cruise
Leg 5), combined with earlier surveys and available geologic information,
provide the basis for interpreting the structure of the continental margin of
Liberia. This area lies at the junction of the Americas and Africa in published
reconstructions of Gondwanaland prior to the opening of the North and
South Atlantic in Jurassic and Cretaceous time, respectively.
Three fracture zones (St. Paul, Cape Palmas, and Grand Cess) are
inferred in the area southeast of 90 30' W. on the basis of magnetic and
gravity data, which is supported by bathymetric and seismic reflection data.
The three fracture zones appear to exist as separate lineaments near the
African coast. Farther seaward, they may be part of the same transform
fault crossing the Atlantic (St. Paul fracture zone). The magnetic anomalies
associated with these fracture zones, which may have originated in
Cretaceous time at the opening of the South Atlantic, are continuous with
magnetic anomalies over crust of Eburnean age (approx. 2,000 m.y.) in
southeast Liberia and its continental shelf. This suggests that Eburnean
age structures may have been zones of weakness that were reactivated in
Cretaceous time.
A positive gravity anomaly (approx. 50 mgal) along the coast and
continental shelf of Liberia is attributed to deep crustal rocks that were
uplifted and exposed in Pan-African time (approx. 500 m.y.). The land
boundary of this anomaly coincides with a shear zone that marks the
boundary between the Pan-African and the Liberian age province (approx.
2,700 m.y.); the shearing (in a thrust-fault sense) may be the result of
compressive stress associated with the closing of a proto-Atlantic ocean.
Liberian age magnetic anomalies in the area northwest of 90 30' W. cross
the Pan-African province (and the positive coastal gravity anomaly) and
continue over the continental shelf and slope to about the 3,000 m
bathymetric contour; the seaward limit of the anomalies is interpreted as
representing the seaward limit of the old continental crust. This westward
extension of the continental crust does not completely fill the gap in fit in
various published reconstructions of Gondwanaland, and we suggest that
the northern Florida block may have been located near the Liberian margin
at one time.
Magnetic data indicate a thick section of sedimentary rock, possibly as
great as 8 km, on the continental slope. Comparison of gravity data over
magnetically inferred basins in the shelf, slope, and rise suggests that
low-density sedimentary rocks constitute a greater proportion of the section
in basins beneath the slope and rise northwest of 90 30' W. than beneath the
slope and rise in the area of the fracture zones. The gravitational attraction

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that corresponds to a crust-mantle boundary dipping 450 to 600 can be
computed to fit observed data-as might be expected at a rifted continental
margin. A shallow high-density block beneath the coast and continental
shelf is required to fit the coastal positive anomaly; this block is represented
by exposures on land of granulite-grade metamorphic rock of the
Pan-African province. (authors' abstract)

BUFFLER, RICHARD T., JOEL S. WATKINS, JEANNE F. SHAUB, and J.
LAMAR WORZEL, 1980, Structure and early geologic history of the deep
central Gulf of Mexico basin, in Pilger, R. H. (editor), The origin of the Gulf of
Mexico and the early opening of the central North Atlantic Ocean:
Proceedings of a symposium, March 3-5, 1980, Louisiana State University,
Baton Rouge, Louisiana, pp. 3-16.
Multifold seismic reflection data (27,000 km) and OBS refraction data
collected recently by the University of Texas Marine Science Institute in the
deep Gulf of Mexico provide the basis for a preliminary interpretation of the
early (pre-middle Cretaceous) geologic history of the basin. The following
observations can be made regarding the structure and stratigraphy of the
deep central Gulf: 1) a thinned and rifted "transitional" crust (6-20 km thick)
underlies the southern part of the deep central Gulf and extends up to 100
km seaward of the Campeche Escarpment; 2) the upper part of this
transitional crust in places contains rift basins; 3) a major unconformity
(strong, smooth reflector) truncates this transitional crust; 4) an oceanic
crustal layer (5-6 km thick) underlies the rest of the central Gulf. The top of
this layer corresponds to a strong irregular reflector seen on the seismic
reflection data; 5) an outer basement high occurs along the boundary
between oceanic crust and transitional crust; 6) a thick salt section overlies
the transitional crust. It is bounded on the north and west by the outer
basement high and pinches out depositionally to the south along the base of
the Campeche Escarpment against the major unconformity (3 above). Salt
appears to be absent or possibly very thin in the areas of oceanic crust; 7)
there was an early period of deformation of salt and sedimentary rocks
probably due to gravity flowage of the salt associated with the early rapid
subsidence of the basin; 8) a younger undeformed sedimentary sequence
onlaps the oceanic crust, the outer basement high and the deformed salt
and sedimentary rocks. The upper part of this sequence probably
represents the deepwater equivalent of the Lower Cretaceous carbonate
banks that rimmed the early Gulf basin; 9) these older sedimentary
sequences are truncated by a major regional unconformity that is
tentatively correlated with a major middle Cretaceous (Cenomanian 97
m.y.) unconformity and drop in sea level.
The symmetrical distribution of transitional crust and thick salt on either
side of oceanic crust as well as other data suggest that the Gulf basin
evolved somewhat along the same lines as the North Atlantic, both as to
timing and as to structure and stratigraphy. A model for the early evolution
of the Gulf is proposed based on our interpretations and consists of four
main phases as follows: a) a long period (Triassic-Early Jurassic) of

INFORMATION CIRCULAR NO. 98

regional uplift, doing, rifting, erosion and filling of rift basins with
continental sediments and volcanics (Rift Phase). Formation of thinned
continental crust or transitional crust; b) formation of a medial uplift due to
mantle upwelling (Late Rift Phase). Initial subsidence, incursion of
seawater and deposition of thick shallow-water evaporites in basins on
either side of medial uplift (Middle Jurassic); c) a period of seafloor
spreading in Late Jurassic-Early Cretaceous and formation of oceanic crust
(Drift Phase). Rapid subsidence of the basin due to cooling of the crust.
Deposition of deep-water sediments in the central Gulf and shallow-water
sediments on adjacent margins overlying the salt. Early deformation due to
gravity flowage of salt basinward; and d) abortion of seafloor spreading due
to major plate reorganization about 130 m.y. ago. Continued subsidence of
the basin through Lower Cretaceous as crust continues to cool
(Subsidence Phase). Deposition of deep-water sediments across the deep
basin and buildup of carbonate banks on the margins controlled by a
structural hinge zone. Formation of a major middle Cretaceous (97 m.y.)
unconformity due to a combination of a continued subsidence and a major
drop in sea level. (authors' abstract)

DANIELS, DAVID L., ISADORE ZEITZ, and PETER POPENOE, 1983,
Distribution of subsurface Lower Mesozoic rocks in the southeastern
United States as interpreted from regional aeromagnetic and gravity
maps, in Gohn, Gregory S. (editor), Studies related to the Charleston,
South Carolina, earthquake of 1886-tectonics and seismicity: U. S.
Geological Survey Professional Paper 1313-K, 24 p.
Aeromagnetic data, in conjunction with data from deep wells, are used
to interpret the nature of the pre-Cretaceous "basement" beneath the
Coastal Plain in Georgia and South Carolina. These data reveal some of the
complexity of the broad early Mesozoic rift basin, which appears to extend
at least from the Gulf of Mexico to the Atlantic Ocean. Along the northern
edge of this rift, in the Savannah River region, depth-to-magnetic-source
calculations delineate two interconnected basins, which are separated from
the main rift by a broad horst of crystalline basement. The Riddleville (Ga.)
basin appears to contain at least a 2.2-km thickness of basin fill; it is deeper
than the Dunbarton (S. C.) basin, which has at least a 1.0 km thickness of
fill. A maximum thickness of 3.5 km near Statesboro, Ga., is indicated for
the main basin, called here the South Georgia rift.
Abundant lower Mesozoic diabase dikes in the South Carolina Coastal
Plain are revealed on the magnetic map by narrow anomalies that have two
dominant trends, northwest and north. One set of several north-trending
anomalies can be traced continuously northward across the Coastal Plain,
Piedmont, and Blue Ridge for 480 km. The two sets, which may represent
two episodes of intrusion, have characteristic distributions within the study
area: northwesterly trends are to the southwest and northerly trends to the
northeast. A broad area of overlap extends from 800 W., in South Carolina,
to northern Virgina. Several lower Mesozoic diabase sills within the rift are
indicated by circular, low-amplitude magnetic anomalies.

BUREAU OF GEOLOGY

Intense magnetic highs and corresponding gravity highs indicate the
presence of abundant large bodies of mafic rocks in the pre-Cretaceous
"basement" in addition to the dikes and sills; two groups of mafic rocks are
distinguished. Circular or oval anomalies are interpreted as largely
gabbroic plutons, which may be as young as early Mesozoic and which are
present both within and outside the rift. Elongate anomalies, which form a
northeast-trending belt across Georgia and South Carolina, may reflect
deformed pre-Mesozoic mafic rocks.
The largest and least understood magnetic feature of the region is the
Brunswick anomaly, a long-wavelength anomaly system 1,100 km long,
which is mostly offshore but which also bisects the Georgia Coastal Plain.
The anomaly divides two regions of differing magnetic character and
magnetic trend, which suggests that it is closely related to a Paleozoic
suture between a Florida-South Georgia microcontinent and the North
American craton. (authors' abstract)

DICKINSON, WILLIAM R., and PETER J. CONEY, 1980, Plate tectonic
constraints on the origin of the Gulf of Mexico: in Pilger, R. H. (editor), The
origin of the Gulf of Mexico and the early opening of the central North
Atlantic Ocean: Proceedings of a symposium, March 3-5, 1980, Louisiana
State University, Baton Rouge, Louisiana, pp. 27-36.
Drift history and plate interactions within the Caribbean region place
severe constraints on hypotheses for the origin of the Gulf of Mexico.
Various crustal elements of South America and Mesoamerica were sutured
against North America when a Paleozoic ocean closed along the Ouachita
segment of the Hercynian orogenic belt. Triassic positions for crustal blocks
within Pangaea leave little or no space for a pre-Jurassic oceanic area in the
region south of the North American craton. Lack of evidence for any
Mesozoic or Cenozoic subduction around most margins of the present Gulf
implies that the crustal blocks which separated during the Mesozoic to form
the oceanic floor of the central Gulf were largely those that still rim the Gulf
today. Prior to Jurassic opening of the Gulf, the Yucatan block including the
Campeche bank thus nestled against the southern United States and
eastern Mexico. Subsequent independent motion of Yucatan later in the
Mesozoic was accommodated either by a northwesterly trending mega-
shear that sliced through Mexico, or by a northerly trending transform that
crossed the present Isthmus of Tehuantepec. The positioning of Cuba
across the mouth of the Gulf between Yucatan and Florida was
accomplished by subduction along the northern flank of the Greater Antilles
from medial Cretaceous to mid-Paleogene times. The western limit of the
subduction zone was a transform or trans-tensional rift along the eastern
edge of the Yucatan block. Northward motion of the greater Antilles relative
to North America continued until collision of Cuba with the Bahama
platform, whose crustal bulk effectively resisted subduction. Subsequent
Neogene subduction of Atlantic lithosphere beneath the Caribbean plate
has been confined to the Lesser Antilles arc-trench system. Coordinate
Neogene transform slip along the north side of the Caribbean plate has

INFORMATION CIRCULAR NO. 98

opened the Cayman trough, and displaced nuclear Central America from its
original Paleogene position south of the Sierra Madre del Sur. (authors'
abstract)

DIETZ, ROBERT S., JOHN C. HOLDEN, and WALTER P. SPROLL, 1970,
Geotectonic evolution and subsidence of Bahama Platform: Geological
Society of America Bulletin, vol. 81, pp. 1915-1928.
The thick section (greater than 5 km) of flat-lying Cretaceous and
younger carbonates capping the Bahama platform implies an unusual
geotectonic history, characterized by great subsidence. We suggest that
this platform is underlain neither by sial nor by a volcanic foundation
creating a "mega-atoll." Instead we propose a basement of oceanic crust
about 11 km down which has undergone slow subsidence. Triassic rifting in
the Atlantic probably initially created a closed small ocean basin, or
mediterranean, in the Bahama region. This was accomplished by a
rotational movement of the North American plate away from North Africa
accompanied by shearing across the top of the South American plate which
remained stationary and attached to Africa. A wedge-shaped spheno-
chasm resulted which became a sediment trap within Pangaea and quickly
filled to sea level with turbidites. With renewed continental drift, the Bahama
platform became a subsiding marginal plateau attached to the North
American craton upon which algal-coral growth exposively flourished under
holo-oceanic conditions, providing sufficient upbuilding to offset subsid-
ence and maintain a sea level freeboard.
This interpretation obviates the overlap of the Bahama salient onto the
African craton when the Atlantic Ocean is closed under continental drift
reconstruction. It accounts for the long history of subsidence without calling
on "oceanization." It also explains the inference, based on some
Cuban-Soviet geophysical evidence, that there is a thick sedimentary
section beneath the Bahamian carbonates. An underlying plastic sequence
could also include the source of the probable salt domes at the bottom of
Exuma Sound. (authors' abstract)
Note that, as the authors point out in their development of the model,
although the discussion is primarily restricted to the Bahama platform, the
explanation could possibly include contiguous geologically similar regions,
i.e., the southern one-fourth of Florida and a portion of the Blake marginal
plateau. Also, as discussed in the conclusion of the paper, if the inferred
Lower Mesozoic plastic section is verified, it should offer good oil and gas
prospects with deep drilling.

DILLON, WILLIAM P., and CHARLES K. PAUL, 1982, Summary of
development of the continental margin off Georgia based on multichannel
and single-channel seismic-reflection profiling and stratigraphic well data:
in Arden, Daniel P., Barry F. Beck, and Eleanor Morrow, (editors),
Proceedings of the second symposium on the geology of the Southeastern
Coastal Plain: Americus, Georgia, March 5-6, 1979, Georgia Geological
Survey Information Circular 53, pp. 197-200.

BUREAU OF GEOLOGY

The U. S. Geological Survey has collected a grid of 9,000 km of deep
penetration, common-depth-point, seismic reflection profiles on the U. S.
southeastern continental margin in order to study the structure, develop-
ment, and petroleum potential of the region. Profile TD-5 extends from the
outer part of the Southeast Georgia Embayment, across the northern end of
the Blake Plateau basin, and eastward to the deep sea. It passes through
three deep drill sites which provide stratigraphic control. Along with
knowledge gained from the remainder of the grid, profile TD-5 is used to
characterize the development of the continental margin off Georgia. A
summary of this development is given by the authors:
"The continental margin off Georgia probably began to form with
rifting, mafic intrusive and extrusive activity, and rapid sediment
deposition which led to development of a transitional basement.
Early subsidence was rapid for the basement beneath the present
Blake Plateau basin, and the Upper Jurassic deposits form the
thickest unit. Reefs acted as sediment dams at the seaward side
of the basin. Near the end of the Neocomian, the reefs died, but a
new reef formed slightly to landward and continued to form a
sediment dam until the end of the Early Cretaceous. Subse-
quently, the Blake Plateau has been a moderately deep water
environment (several hundred meters) until present: The Gulf
Stream became significant on the Blake Plateau near the
Paleocene-Eocene boundary, and since then has prevented the
shelf sediments from prograding across the plateau."

DILLON, WILLIAM P. and JEAN M. A. SOUGY, 1974, Geology of West
Africa and Canary and Cape Verde Islands: in, Nairn, Alan E. M. and
Francis G. Stehli, (editors), The ocean basins and margins; Volume 2, The
North Atlantic: Plenum Press, New York, pp. 315-390.
Research and study of the geotectonic history of the Florida basement
requires familiarity with West African geology. This paper is an excellent
reference work on West African geology. It includes detailed descriptions of
the structural framework and geologic history, from Precambrian to
Quaternary, of West Africa and the Canary and Cape Verde Islands.

DRAKE, C. L., J. HEIRTZLER, and J. HIRSHMAN, 1963, Magnetic
anomalies off eastern North America: Journal of Geophysical Research,
vol. 68, pp. 5259-5274.
Numerous magnetic profiles have been made across the continental
margin of eastern North America by the U. S. Geological Survey, the U. S.
Navy Hydrographic Office, and the Lamont Geological Observatory. These
data, supplemented by area studies in parts of the region, reveal an
anomaly pattern which is essentially parallel to the margin and to the major
structural features on shore. Calculations show that, while basement
topography may contribute, the principal causes of the anomalies are
compositional changes within the basement. Two exceptions to the pattern
are noted; one is southern Florida, suggested by E. R. King (1959) to be an

INFORMATION CIRCULAR NO. 98

extension of the Ouachita system, and the other is a major feature normal to
the coast at latitude 400 N interpreted as being associated with a
transcurrent fault. Other geophysical and geological observations indicate
a right lateral displacement of the fault of about 100 miles and a total length
in excess of 600 miles. The implications of this and the possibility of other
transcurrent movements along the Atlantic margin are examined. (authors'
abstract)

FREELAND, GEORGE L., and ROBERT S. DIETZ, 1971, Plate tectonic
evolution of Caribbean-Gulf of Mexico region: Nature, vol. 232, pp. 20-23.
A geotectonic model for the evolution of the "American Mediterranean"
(Caribbean-Gulf of Mexico region) is presented. Microcontinents, which are
later translated, eliminate the overlaps and oceanic areas in the Paleozoic
reconstruction of the region by Bullard et al. (1965). Areas underlain by
pre-Mesozoic basement are included in the microcontinents; neo-cratons
(i.e. "new ground" created during Mesozoic-Cenozoic time) are eliminated.
The microcontinents included Oaxaca (southern Mexico), Yucatan,
Honduras-Nicaragua, and southeastern Bahama platform (the nature of
the Blake-Florida-Bahama platform basement is still unknown; for this
reconstruction it is assumed to be pre-Mesozoic). The evolution of the
Caribbean-Gulf of Mexico region, including the rotation and translation of
these microcontinents, as related to the tectonic motions of the North
American, South American, and African plates, is shown in seven
time-sequence reconstructions from Paleozoic to present.

HALL, D. J., T. D. CAVANAUGH, J. S. WATKINS, and K. J. McMILLEN,
1982, The rotational origin of the Gulf of Mexico based on regional gravity
data: in Watkins, J. S. and C. L. Drake (editors), Studies in continental
margin geology: American Association of Petroleum Geologists Memoir
34, pp. 115-126.
Regional free-air gravity data from the Gulf of Mexico define
deep-seated linear features which we interpret as outer marginal basement
highs. Highs are arranged symmetrically around the deep water Gulf.
Abrupt changes in trend occur along three well-defined zones on both sides
of the central Gulf. The marginal high off Galveston parallels the
Cretaceous Edwards Reef trend 230 km to the northwest. We interpret the
seaward limits of these outer marginal highs as close to the landward edges
of oceanic crust. The crust in the area from the continental hinge zone (near
which the Edwards Reef developed) to the outer high is thinned, faulted,
and intruded by mafic dikes, but probably has a nearly continental overall
composition.
We infer that the Gulf opening followed a pattern of early rifting and
subsequent sea-floor spreading. Our model implies that the thick salt
deposits underlying the modern Texas slope were deposited on sediments
overlying oceanic crust. Thinner salt deposits overlie pre-salt sediments on
rift-stage crust both northwest of the Texas outer marginal high and in the
Sigsbee Knolls. A change in the location of the sea-floor spreading center

BUREAU OF GEOLOGY

led to separation of the two main salt depo-centers beneath the Sigsbee
Knolls and along the Texas-Louisiana shelf and slope. Recent paleomag-
netic evidence (L. Sanchez Barreda, personal communication, 1981)
indicates a post-Permian, 24 clockwise rotation of Chiapas relative to
Oaxaca (this is consistent with our rotational model). The Salina Cruz fault,
crossing the Isthmus of Tehuantepec between the Permian outcrops in
Chiapas and Oaxaca, was probably a major transform fault active during
the Gulf opening. (authors' abstract)

HORTON, J. WRIGHT, JR., ISIDORE ZIETZ, and THORTON L.
NEATHERY, 1984, Truncation of the Appalachian Piedmont beneath the
Coastal Plain of Alabama: Evidence from new magnetic data: Geology,
vol. 12, pp. 51-55.
A new aeromagnetic survey of a part of southern Alabama reveals that
magnetic signatures of the Appalachian Piedmont are truncated by a major
magnetic lineament beneath the Gulf Coastal Plain. Mylonitic rocks have
been recovered from a drillhole along this lineament, which is probably a
fault zone of late Paleozoic and/or Triassic-Jurassic age. We suggest that
this fault zone may initially have been the Alleghanian convergent suture
between the North American craton and accreted terranes to the southeast.
The zone may have been locally reactivated as part of an extensive buried
Triassic-Jurassic graben system. (authors' abstract)

IBRAHIM, ABOU-BAKR K., J. CARYE, G. LATHAM, and RICHARD T.
BUFFLER, 1981, Crustal structure in Gulf of Mexico from OBS refraction
and multichannel reflection data: American Association of Petroleum
Geologists Bulletin, vol. 65, pp. 1207-1229.
Results from 12 reversed refraction profiles each 110 km long have
been combined with multichannel reflection data to produce a series of
crustal structure sections across the Gulf of Mexico. These data show as
many as three layers of sedimentary rocks with total thickness between 5
and 9 km and layer velocities between 1.7 and 3.5 km/sec. Beneath most of
the Gulf, this sedimentary section is underlain by a layer with velocity
between 4.5 and 5.5 km/sec. The acoustic basement as defined by
reflection data is confined within this layer. Beneath this layer in most of the
deep Gulf is an oceanic crustal layer, 3 to 6 km thick which thickens to about
12 Km under the Mississippi fan and 10 km in the southeastern Gulf where it
is interpreted to be transitional crust. This layer has a velocity between 6.4
and 7.0 km/sec and overlies a mantle with velocity between 7.6 and 8.2
km/sec.
These data confirm earlier refraction interpretation that most of the
deep Gulf basin is underlain by an oceanic crustal layer flanked by
transitional crust. This layer may have been formed by a mantle thermal
event accompanied by a period of rapid sea-floor spreading. (from authors'
abstract)

IBRAHIM, ABOU-BAKR K. and ELAZAR UCHUPI, 1982, Continental

INFORMATION CIRCULAR NO. 98

oceanic crustal transition in the Gulf Coast geosyncline: in, Watkins, J. S.
and C. L. Drake (editors), Studies in continental margin geology: American
Association of Petroleum Geologists Memoir 34, pp. 155-165.
Seismic refraction measurements indicate that the transition from
rifted continental crust to oceanic crust takes place at a water depth of over
3000 m northwest of Cuba between the Florida and Campeche
escarpments. Along the eastern flank of the Mississippi Embayment, the
transition occurs at about 2500 m deep and on the embayment itself
inboard of the coast. Off south Texas the boundary between the rifted
continental crust and oceanic crust is near the shelf's edge, off Mexico the
boundary is on the continental slope, and off Campeche Bank the boundary
is about 100 km northwest of Campeche Escarpment. In the northern Gulf
an oceanic crustal high may lie beneath the upper continental slope. This
high served as a foundation for a Mesozoic reef. Maximum sediment
accumulation took place along the contact between the rifted continental
crust and oceanic crust. (authors' abstract)

KLITGORD, KIM D., WILLIAM P. DILLON, and PETER POPENOE, 1983,
Mesozoic tectonics of the southeastern United States Coastal Plain and
continental margin: in Gohn, Gregory S. (editor), Studies related to the
Charleston, South Carolina, earthquake of 1886-tectonics and seismicity:
U. S. Geological Survey Professional Paper 1313-P, 15p.
Many of the major structures associated with Paleozoic and Mesozoic
tectonic events along the Southeastern U. S. Coastal Plain and continental
margin have distinctive geophysical and geological properties, which are
described in this integrated study of magnetic, gravity, seismic-reflection,
and drill-hole data. These data are used to identify three major tectonic
boundaries that separate terranes of Paleozoic, Triassaic, and Jurassic
tectonic activity and to map sedimentary basins that were formed by
Triassic and Jurassic rifting events. The major tectonic boundaries are: (1)
An offshore hinge zone in basement that separates an area of crustal
subsidence associated with the Jurassic-age marginal basins from an area
of significantly less subsidence associated with Triassic and older
basement structures to the west; (2) a line of narrow grabens, associated
with the magnetic low in the Brunswick magnetic anomaly, that separates a
Paleozoic basin underlying northeastern Florida, which was not greatly
affected by late Paleozoic or Triassic tectonic activity, from a broad zone of
considerable Triassic tectonic activity and sediment accumulation in the
Charleston, S. C., region; and (3) a narrow east-west zone near 330 N that
separates the geophysically distinctive northeast-trending Piedmont to the
north from the Charleston region. The Triassic sedimentary basins are of
two types: (1) narrow basins or grabens within the Piedmont and along the
major tectonic boundaries and (2) broad zones of sediment accumulation
over a block-faulted Paleozoic basin in northwestern Florida and in areas
delineated by low-gradient magnetic and gravity fields in parts of the
Charleston region. Deep continental margin basins, containing sedimenta-
ry rock as much as 14 km thick, formed at sites of Jurassic rifting and

BUREAU OF GEOLOGY

subsequent ocean opening seaward of the basement hinge zone.
Reconstruction of the positions of the North American, South American,
and African continents during the Early Jurassic provides a framework for
relating the Mesozoic tectonic events and structures to major Paleozoic
orogenic events and lithotectonic units. (authors' abstract)

LADD, JOHN W., 1976, Relative motion of South America with respect to
North America and Caribbean tectonics: Geological Society of America
Bulletin, vol. 87, pp. 969-976.
Magnetic anomalies in the North Atlantic have been analyzed by
Pitman and Talwani (1972) to determine a sequence of finite difference
poles of relative motion of North America with respect to Africa for the time
period 180 m.y. B.P. to the present. A similar analysis of South Atlantic
magnetic anomalies by the writer determines a sequence of finite difference
rotations of South America with respect to Africa for the time period 127 m.y.
B.P. to the present. The two sequences of finite difference rotations are
used to calculate the relative motion of South America with respect to North
America for late Mesozoic and Cenozoic time.
From Triassic to Early Cretaceous time, South America moved to the
southeast away from North America. From Early Cretaceous to Late
Cretaceous time, South Amerca moved eastward with respect to North
America. Southeastward motion of South America occurred again from
Late Cretaceous to early Tertiary time followed by northward motion from
early to late Tertiary. Tectonic styles in the Caribbean region change when
major plate motions change; however, the details of Caribbean geology
cannot be explained by simple plate margins between North and South
America. Tertiary compressional structures on the northern and southern
margins of the Caribbean can be attributed to Tertiary closure between
North and South America, but earlier tectonic regimes are not so easily
related directly to North America-South America motions. (authors'
abstract)

MULLINS, HENRY, T., and GEORGE W. LYNTS, 1977, Origin of the
northwestern Bahama Platform: Review and reinterpretation: Geological
Society of America Bulletin, vol. 88, pp. 1447-1461.
The origin of the Bahama Platform has been the subject of debate for
more than a century. The major points of disagreement are (1) whether the
Bahamian basement is continental or oceanic, and (2) the age and origin of
the deep Bahama channels. Geophysical data indicate only that the
Bahamian basement is of intermediate density, seismic velocity, and
thickness. We propose that this basement was originally pre-Triassic
continental material that was pervasively intruded by mafic and ultramafic
material during the rifting of North America from Africa and South America
in Late Triassic time. To alleviate the Bahama overlap in reconstructions of
the North Atlantic we suggest that the Bahama Platform has been rotated
approximately 25 to the northeast by the relative impinging motion of the
Caribbean plate during Cretaceous and early Tertiary time. By accounting

INFORMATION CIRCULAR NO. 98

for this postulated rotation, the Bahama Platform forms an excellent fit
between Africa and South America.
We propose the following model for the origin of the northwestern
Bahama Platform: (1) The platform is continental and was originally part of
Africa. (2) Rifting of North America from Africa and South America began in
the vicinity of the northwestern Bahamas during the Late Triassic, preceded
by a large domal uplift of the continents that initiated the deep Bahama
Channels as grabens. (3) The Bahama Platform rifted from Africa
principally along a large right-lateral shear and thus evolved as a
transcurrent-type continental margin. (4) During the incipient development
of the deep Bahama channels, Late Triassic continental arkosic rudites and
arenites were deposited at the base of these grabens; (5) Initial marine
conditions in Early to Middle Jurassic time may have resulted in the
deposition of salt and organic-rich shales in the channels due to restricted
circulation. (6) With the onset of more open marine conditions 3 to 6 km of
Jurassic to Holocene deep-water carbonate and bioclastic turbidite
sediments were deposited in the channels. (7) Most of the intraplatform
relief of the northwestern Bahamas appears to be the result of the build-up
of the banks relative to the channels during regional subsidence. (authors'
abstract)

PILGER, REX H., JR., 1978, A closed Gulf of Mexico, pre-Atlantic Ocean
plate reconstruction and the early rift history of the Gulf and North Atlantic:
Gulf Coast Association of Geological Societies Transactions, vol. 28, pp.
385-393.
Several diverse lines of evidence indicate that the pre-Gulf of Mexico
position of South America was adjacent to the northern Gulf Coast of North
America in earliest Mesozoic time, as originally suggested by Walper and
Rowett (1972). These include: 1) correlation of the boundary between
Hercynian and pre-Hercynian terranes in Africa with the subsurface
boundary between the southern Appalachians and the Florida platform in
North America, 2) similarities in the inferred Triassic history of the Gulf and
Atlantic coasts of North America; 3) recognition of significant left-lateral
faulting in Mexico and Central America, which indicates more westerly
positions of the various crustal blocks of Middle America prior to initiation of
drift and, consequently, eliminates overlap of South America and Mexico of
other reconstructions; 4) accommodation of the Florida-Bahama platform
(assumed to be continental) by subsequent crustal extension and
left-lateral faulting; 5) accommodation of Atlantic coast-Africa overlaps by
crustal extension reflected in the on and offshore Triassic basins, and 6)
satisfaction of paleomagnetic data which seem to require more northerly
positions of the Gondwana continents relative to the Laurasian continents
in latest Paleozoic and earliest Mesozoic time.
The post-rifting history inferred from the reconstructions and other
constraints suggests the Gulf began opening in a north-south direction in
early Mesozoic time, while right-lateral, obliquely divergent movement was
occurring along the Atlantic coast between Africa and North America. Such

BUREAU OF GEOLOGY

motion was accommodated in part by formation of the Triassic rift basins.
Subsequently, in late Triassic time, Africa and South America began
moving in a southeasterly direction relative to North America. During this
period, and into the early Jurassic, the Florida-Bahama platform was
extended and emplaced along left-lateral faults roughly parallel to the
direction of plate motion. Eastward motion of Mexico and Central America
along left-lateral faults continued with opening of the Gulf of Campeche in
Jurassic time, and movement of the various crustal fragments of Middle
America into the Caribbean region during the Cretaceous and early
Cenozoic. Contemporary east-west left-lateral movement is occurring
along the plate boundary separating the North American and Caribbean
plates.
These inferences suggest that the Gulf of Mexico is older than the
Atlantic, and is underlain by the oldest oceanic crust still preserved in the
world ocean basins. Further, it is likely that initial fragmentation of
Gondwana from Laurasia involved a large component of strike-slip motion,
concentrated along the axes of the older Appalachian-Hercynian mountain
belts. (author's abstract)

SHERIDAN, ROBERT E., and WILLIAM L. OSBURN, 1975, Marine
geophysical studies of the Florida-Blake Plateau-Bahamas Area: in
Yorath, C. J., E. R. Parker and D. J. Glass, (editors), Canada's continental
margins and offshore petroleum exploration: Canadian Society of
Petroleum Geologists Memoir 4, pp. 9-33.
Marine seismic refraction and reflection profiles correlated with deep
wells on land reveal that the Blake Plateau is underlain by 7-11 km of
Jurassic and younger carbonates and evaporites, with some terriginous
sediments. Rock dredges and cores show that the area is bordered by an
apparently continuous reefal complex of Cretaceous and earlier age which
extends from the Blake Escarpment through the Bahamas and Cuba to the
West Florida Escarpment. JOIDES drilling on the Blake Plateau indicates
that the Tertiary sedimentary section is abbreviated due to the erosional
sweeping of the Gulf Stream. JOIDES Deep Sea Driling Project results and
more recent piston coring reveal a complex Cenozoic history of
hemipelagic and turbidite deposition in the Blake-Bahama Basin and on the
Blake Outer Ridge. Contour currents apparently built the Outer Ridge then
shifted deposition west of the ridge into the basin in the Late Miocene.
The origin of the basement under the Blake Plateau and Bahamas is
still unknown from direct evidence. Indirect geophysical evidence, including
magnetic anomalies, and Rayleigh Wave dispersion data, suggest the
possibility that the basement is about 10 km deep and of intermediate
density and seismic velocity. Such a crust might be correlated with that of
the present Red Sea, and the Blake Plateau-Bahamas crust could be
interpreted to have formed in a similar way in the Jurassic, or possibly the
Triassic, as North America and Africa rifted apart. Basement faulting
associated with the rifting and plate rotation of North America controlled the

INFORMATION CIRCULAR NO. 98

formation and subsidence of the deep geosynclinal basin under the Blake
Plateau.
Porous dolomite horizons and cavernous reefal limestone are known
in the area. Regional dip caused by differential subsidence of compaction
over reefs, faults affecting Cretaceous and older strata, and possible salt
doing might offer entrapment situations for these existing reservoirs.
Golden Lane analogies and Smackover continuations are possible and
stratigraphic traps are very probable. The potential for large petroleum
reserves is real but their exploration and exploitation will be difficult.
(authors' abstract)

TANNER, WILLIAM F., 1965, The origin of the Gulf of Mexico: Gulf Coast
Association of Geological Societies, Transactions, vol. 15, pp. 41-44.
The Gulf of Mexico dates from approximately the Paleozoic-Mesozoic
time boundary. From structural considerations, the hypothesis is developed
that the present Gulf is the result of a slowly-widening rift, or tension gap,
between North America and Central America and the Caribbean block. A
general program of investigations, designed to test or at least explore the
hypothesis, is outlined. (from author's abstract)
TODD, R. G., and R. M. MITHCUM, JR., 1975, Seismic stratigraphic
identification of eustatic cycles in Late Triassic, Jurassic, and Early
Cretaceous rocks, Gulf of Mexico and West Africa: Gulf Coast Association
of Geological Societies Transactions, vol. 25, pp. 41-43.
Seismic stratigraphic techniques permit identification of Late Triassic,
Jurassic, and Early Cretaceous eustatically controlled sequences in strata
from the North American Gulf Coast and West Africa. Several distinct
sequences are remarkably persistent from the Florida panhandle around
the perimeter of the Gulf Coast into northern Mexico, a distance of over
1,500 miles. Their identification requires the integration of seismic data with
lithologic, environmental-facies, biostratigraphic, radiometric, and well log
information. A comparison with strata of comparable age in offshore West
Africa are interpreted to be eustatically controlled because they occupy the
same time-stratigraphic positions and display coastal onlap patterns similar
to those previously recognized by us elsewhere in the world. (from authors'
abstract)

VAN DER VOO, R., F. J. MAUK, and R. B. FRENCH, 1976,
Permian-Triassic continental configurations and the origin of the Gulf of
Mexico: Geology, vol. 4, pp. 177-180.
Previously published reconstructions of Pangea during the late
Paleozoic-early Mesozoic time have suggested that (1) the Gulf of Mexico
has existed as an oceanic basin from at least the late Carboniferous onward
or (2) the Gulf of Mexico was created since Permian time by a process of
microplate reorganization, macroplate drift, or oceanization (sensu stricto.
On the basis of paleomagnetic data, we favor macroplate drift. Major
geologic and tectonic features of the Pangea segments bordering the Gulf

INFORMATION CIRCULAR NO. 98

ranging from approximately 0.8 to 2.6 km. Depths of the underlying Lower
Cretaceous rocks (density of 2.30 to 2.55 gm/cm3) extend to approximately
1.4 km in north Florida and more than 4.7 km in south Florida. An abrupt
north-to-south increase in average basement rock density from 2.73 to 3.00
gm/cm3 is evident along a general east-west trending zone passing through
the central portion of the peninsula. This supports a concept of a
north-to-south transition from continental to oceanic type rocks underlying
the thick sedimentary sequence of the central Florida peninsula. (authors'
abstract)
WILSON, GARY V., 1975, Early differential subsidence and configuration
of the northern Gulf Coast Basin in southwest Alabama and northwest
Florida: Gulf Coast Association of Geological Societies Transactions, vol.
25, pp. 196-206.
Deep test-well information in southwest Alabama and northwest
Florida indicates that early differential subsidence of the basement had a
marked influence on the thickness and distribution of accumulating coastal
plain sedimentary deposits, especially carbonates, evaporites and thick
marine shale units. Geophysical data reveal that these differential
movements were either directly or indirectly related to lateral variations in
the thickness of crustal layers. These crustal thickness variations may have
been either the cause of differential subsidence of the basement or the
result of deep-seated forces that induced or affected subsidence. Regional
gravity anomalies reflect crustal thickness variations associated with the
Wiggins uplift and the Mississippi interior salt basin. In the study area a
basement high and stratal thinning correspond to the easternmost
extension of the Wiggins uplift and a regional gravity minimum. A basement
low and stratal thickening correspond to the eastern limb of the Mississippi
interior salt basin and a regional gravity maximum.
The configuration of the basin margin during much of Late Jurassic
time was controlled by a hinge line that roughly coincided with a system of
dense intracrustal masses. These masses probably locate a zone of
structural weakness within the crust, basinward from which initial
subsidence and marine deposition took place. The basin margin and extent
of early marine deposition was also influenced by the Wiggins uplift and the
related Conecuh arch. This influence continued until Cretaceous seas
advanced beyond the northern extent of this positive feature. (authors'
abstract)

RELATED REGIONAL AND TECTONIC STUDIES
ANDERSON, THOMAS H., and VICTOR A. SCHMIDT, 1983, The
evolution of Middle America and the Gulf of Mexico-Caribbean Sea during
Mesozoic time: Geological Society of America Bulletin, vol. 94, pp.
941-966.
A plate-tectonic model for the evolution of Middle America and the Gulf
of Mexico-Caribbean Sea region is presented. The model, which is based
upon the existence of the Mojave-Sonora megashear, incorporates into the

BUREAU OF GEOLOGY

of Mexico are in agreement with a newly proposed alternative fit of North
America, Europe, and Gondwanaland for late Paleozoic time. This
reconstruction closes the Gulf of Mexico by juxtaposition of North and South
America. (authors' abstract)

WALPER, JACK L., 1980, Tectonic evolution of the Gulf of Mexico: in
Pilger, R. H. (editor), The origin of the Gulf of Mexico and the early opening
of the central North Atlantic Ocean: Proceedings of a symposium, March
3-5, 1980, Louisiana State University, Baton Rouge, Louisiana, pp. 87-98.
A modification, by Walper and Rowett (1972), of the Paleozoic
reconstruction of Pangea by Bullard et al. (1965) closed the Gulf of Mexico
and placed Mexico and Central America adjacent to northwestern South
America. Further modification of this reconstruction adds another three
degrees of rotation to the 20-degree clockwise rotation of Gondwanaland
proposed by Van der Voo et al. (1976). While this does not significantly
affect the alignment of the pre-Mesozoic orogenic belts of West Africa and
North America, it greatly improves the fit of North and South America. It also
provides a better explanation of late Paleozoic history and the initiation of
rifting that formed the Gulf of Mexico and Caribbean. This history of the Gulf
of Mexico-Caribbean region is given in the author's abstract as follows:
"As the Late Pennsylvanian collision of the Afro-South American
plate with the North American formed Pangea, convergence with
a Pacific plate produced a Permo-Triassic arc-trench system
along much of western North America. It remained active as North
America moved away from a Triassic spreading ridge that passed
from the Pacific into the Gulf and beyond into the North Atlantic,
creating a narrow seaway similar to the Red Sea, in which thick
salt deposits accumulated. As spreading continued and this sea
widened, a Scotia-like arc developed between the diverging North
and South American plates. The Gulf of Mexico evolved on the
trailing margin of the North American plate while the Caribbean
grew from the arc segment as North and South America diverged
and the spreading ridge shifted from the Caribbean to the South
Atlantic. Laramide tectonism, the result of continued convergence
with a Pacific plate, transported Mexico eastward, initiating events
that displaced part of the salt basin and changed the Gulf of
Mexico from a normal trailing plate margin to a vast sediment trap
for Cenozoic erosional debris derived from rejuvenated hinterland
sources."

WALPER, J. J., F. H. HENK, JR., E. J. LOUDON, and S. N. RASCHILLA,
1979, Sedimentation on a trailing plate margin: the northern Gulf of
Mexico: Gulf Coast Association of Geological Societies Transactions, vol.
29, pp. 188-201.
The breakup of Pangaea and the splitting of South America from North
America in the early Mesozoic left a rifted and attenuated trailing margin on
the latter plate which became the initial depositional surface for a

INFORMATION CIRCULAR NO. 98

sedimentary sequence of Late Triassic to Recent age. The Late Triassic
Eagle Mills Formation and its equivalents are interpreted as being the initial
deposits confined to rift grabens of the attenuated plate margin. Deposition
of Jurassic evaporites resulted from sedimentation by the brine mixing
process In the restricted circulation of a young and narrow seaway similar to
the Red Sea. Late Jurassic and Cretaceous strata represent the
transgressive deposits formed as open marine conditions prevailed as the
plates diverged and the North American plate margin subsided. Laramide
tectonism in the continental interior provided a rejuvenated hinterland
source area that supplied the voluminous sediment for the regressive and
prograding Cenozoic plastic wedge.
Studies of this entire sedimentary record reveal the influence of the
tensional effects of continental splitting and lower crustal creep that
established the initial depositional surface that slowly subsided as indicated
by crustal thinning and the thermal decay curve of cooling oceanic
lithosphere. In addition, these studies also reveal the control and influence
of: 1) inherited structures of the rifted margin; 2) hinterland source area; 3)
the timing and amount of differential subsidence between continental and
ocean crust; 4) active syndepositional faults; 5) hingelines; and 6) post
depositional rejuvenation due to contemporary plate movement.
Not only do these studies add to our understanding of the geologic
history of the area, which is most important for development of successful
exploration programs, but they provide a guide for the study of sedimentary
infills within ancient lithospheric plates, a neglected but important task
facing all who are confronted by the complex problem of interpreting the
sedimentary record of ancient basins. (authors' abstract)

WALPER, JACK L., and C. L. ROWETT, 1972, Plate tectonics and the
origin of the Caribbean Sea and the Gulf of Mexico: Gulf Coast Association
of Geological Societies Transactions, vol. 22, pp. 105-116.
Previously published reconstructions of the late Paleozoic "fit" of
crustal plates and continents fail to explain many geological features
present in southwestern United States, Mexico, Central America and
northern South America. In particular, they fail to consider major geologic
and tectonic continuities of Paleozoic age observable in the Southern
Appalachians, the Ouachita and Marathon fold belts, the fold belts of
southern Mexico and Central America, and the eastern Andean Mountain
belt of northern South America, as well as the significance of a number of
major transcurrent fault systems or megashears that cross these regions.
With the well documented Africa-North America join as a control for the
positioning of South America relative to North America, this report suggests
a somewhat different "fit" than any heretofore proposed. Instead of
truncating North America in northern Mexico and filling in the Gulf of Mexico
with fragments as is most commonly done, this reconstruction wraps
Mexico and Central America around the western margin of South America,
thus placing in juxtaposition the major tectonic belts of both continents.
Evidence is also presented indicating that the late Ordovician Taconic

BUREAU OF GEOLOGY

orogeny was an arc-continent collision rather than a continent-continent
collision as has previously been suggested. Similar evidence indicates that
the late Paleozoic Ouachita and Marathon orogenies were arc-continent
collisions. Correlative periods of deformation for both of these orogenies
have been documented from many places in northern and northwestern
South America.
The early Paleozoic history of the Cordilleran mobile belt appears to
have been independent from that of the eastern mobile belt. In the late
Paleozoic, however, these mobile belts seem to have become tectonically
coupled to produce regional stresses that were released along several
major megashears. In southern and southwestern North America these
include the Wichita and Texas megashears; a third megashear is probably
present in northern Mexico. Late Paleozoic movement is probably present
in northern Mexico. Late Paleozoic movement on these fault zones
produced numerous basins and uplifts throughout all of these regions.
Modifications of the model proposed by Malfait and Dinkelman (1972)
for the origin of the Caribbean region are proposed that include the opening
of a sphenochasm in the Gulf of Honduras and regional tensional and
compressional stresses resulting from the clockwise rotation of North
America. The Gulf of Mexico and the present dislocated positions of the
Ouachita and Marathon fold belts are explained as the result of an opening
sphenochasm under the present Mississippi embayment and the westward
displacement of the Ouachita and Marathon fold belts by left lateral
movement on the Wichita and Texas megashears. (authors' abstract)

WILSON, J. TUZO, 1966, Did the Atlantic close and then reopen?: Nature,
vol. 211, pp. 676-681.
Paleontologic, structural, tectonic, and geometric evidence is present-
ed for the hypothesis that, in the Paleozoic, an existing proto-Atlantic Ocean
closed and that, in the Cretaceous, the present Atlantic Ocean opened. In
Early Paleozoic time, the proto-Atlantic formed the boundary between two
distinct faunal realms. During Middle and Late Paleozoic time this ocean
closed by stages, bringing the dissimilar realms together. Available
geological evidence suggests that the present Atlantic Ocean started
opening at the beginning of the Cretaceous. The opening occurred along a
different line than the earlier closing. Fragments of the continents which
were brought together during Middle and Late Paleozoic time thus traded
sides when the present Atlantic opened during the Cretaceous. This
resulted in some regions of similar faunas being separated by the Atlantic
while other regions of dissimilar faunas became adjacent to one another.

WOOD, MICHAEL L., and JACK L. WALPER, 1974, The evolution of the
Interior Mesozoic Basin and the Gulf of Mexico: Gulf Coast Association of
Geological Societies Transactions, vol. 24, pp. 31-41.
The evolution of the Interior Mesozoic Basin is presented in terms of an
evolving Gulf of Mexico which had its origin with the rifting and breakup of
Pangea, particularly with the separation of North and South America. This

INFORMATION CIRCULAR NO. 98

Mesozoic event was preceded by the formation of Pangea in the late
Paleozoic when plate collision produced the Appalachian-Ouachita-Mara-
thon orogeny. As a result of this orogenic episode of plate collision and
accompanying crustal dislocation along three major transcurrent fault
systems, the Texas, Wichita and Mississippi megashears, a proto-Atlantic
was closed and a distributive pattern of pre-Mesozoic rocks was created
that was to have a lasting effect on the shape of the Interior Mesozoic Basin.
Rifting in the early Triassic created an incipient Gulf of Mexico with
associated peripheral grabens that defined the shape of Mesozoic
sedimentation. Crustal thinning and attenuation accompanied the diver-
gent rifting of Pangea and early sedimentation in rift grabens is represented
by the Eagle Mills Formation. Deltaic prisms are postulated, coincident with
the three megashears, and represent the positions of ancestral Rio Grande,
Red and Mississippi Rivers. They augment the continental red beds of the
grabens formed during early rifting and the succeeding marine shelf
sediments of a diverging plate margin and constitute exploratory objectives.
The thick evaporite deposition, represented by the Werner Evaporite
and Louann Salt, in a shallow basin on a subsiding plate margin is the result
of an unique combination of events. The updomed rift margin of the trailing
plate formed a restricting barrier that allowed the continued influx of sea
water into the attenuated and rifted portion of the plate that was subsiding to
form the Interior Mesozoic Basin. The sea water, upon encountering the
highly saline waters of this subsiding basin initiated rapid salt deposition by
the brine mixing method. Eastward rotation of Mexico into its present
position deepened the Gulf of Mexico and peripheral rifting aided in
continued submergence with normal marine deposition being established
in late Jurassic time. (authors' abstract)

WOODS, R. D., and J. W. ADDINGTON, 1973, Pre-Jurassic geologic
framework, Northern Gulf Basin: Gulf Coast Association of Geological
Societies Transactions, vol. 23, pp. 92-108.
Early history of the Gulf basin is conjectural. It was once believed the
basin formed by late Paleozoic foundering of Llanoria, a postulated large
offshore landmass occupying much of the present basin area. Currently,
there are two schools of thought: (1) the basin has existed since late
Precambrian; (2) it was formed by early Mesozoic seafloor spreading in the
Gulf, a product of the general breakup of old Pangaea into continental
blocks.
Upper Paleozoic orogeny, in phase with or a part of a west-southwest-
ward continuation of Appalachian folding, created a northern structural rim
for the basin which strongly influenced subsequent sedimentation and
structural trends. Post-orogenic tension faulting along and south of this rim
was particularly active during the Triassic. Jurassic sediments along the
flank and gulfward from the structural rim overlie this faulted basin floor and
are in unconformable contact with rocks ranging in age from Triassic to
Mississippian.
Triassic sediments are fluvial to deltaic red beds. Paleozoic deposits

38 BUREAU OF GEOLOGY

include both "Ouachita faces" and unmetamorphosed fluvial to offshore
marine plastic and highly fossiliferous shallow water carbonates. Seismic
data suggest Traissic and/or late Paleozoic sediments underlie Jurassic
throughout the Gulf Basin. These pre-Jurassic rocks comprise a large, very
sparsely tested frontier for oil and gas. (authors' abstract)

INFORMATION CIRCULAR NO. 98

REFERENCES
(This is a list of references cited within the bibliography.)

Anderson, Thomas H., and Victor A. Schmidt, 1983, The evolution of
Middle America and the Gulf of Mexico-Caribbean Sea during Mesozoic
time: Geological Society of America Bulletin, vol. 94, pp. 941-966.

Bullard, E., J. E. Everett, and A. G. Smith, 1965, The fit of the continents
around the Atlantic: in Symposium on continental drift: Royal Society of
London Philosophical Transactions, series A, vol. 258, no. 1088, pp. 41-51.

Dietz, Robert S., John C. Holden, and Walter P. Sproll, 1970, Geotectonic
evolution and subsidence of Bahama Platform: Geological Society of
America Bulletin, vol. 81, pp. 1915-1928.

Dillon, William P., and Jean M. A. Sougy, 1974, Geology of West Africa and
Canary and Cape Verde Islands: in Nairn, Alan E. M. and Francis G. Stehli
(editors), The ocean basins and margins; vol. 2, The North Atlantic: Plenum
Press, New York, pp. 315-390.

Freeland, George L., and Robert S. Dietz, 1972, Plate tectonic evolution of
the Caribbean-Gulf of Mexico Region: Proceedings of the sixth
Caribbean Geological Conference, pp. 259-264.

King, Elizabeth R., 1959, Regional magnetic map of Florida: American
Association of Petroleum Geologists Bulletin, vol. 43, pp. 2844-2854.

LePichon, X. J. C. Sibuet, and J. Francheteau, 1977, The fit of the
continents around the North Atlantic Ocean: Tectonophysics, vol. 38, pp.
169-209.

Malfait, Bruce T., and Menno G. Dinkelman, 1972, Circum-Caribbean
tectonic and igneous activity and the evolution of the Caribbean plate:
Geological Society of America Bulletin, vol. 83, pp. 251-272.

Pitman, Walter C., 11l, and Manik Talwani, 1972, Sea-floor spreading in the
North Atlantic: Geological Society of America Bulletin, vol. 83, pp. 619-646.

Talwani, M., J. L. Worzel, and M. Landisman, 1959, Rapid gravity
computations for two-dimensional bodies with application to the
Mendocino submarine fracture zone: Journal of Geophysical Research,
vol. 64, pp. 49-59.

Uchupi, E., J. D. Milliman, B. P. Luyendyk, C. O. Bowin, and K. O. Emery,
1971, Structure and origin of southeastern Bahamas: American Associa-
tion of Petroleum Geologists Bulletin, vol. 55, pp. 687-704.

40 BUREAU OF GEOLOGY

Vail, P. R., R. M. Mitchum, Jr., R. G. Todd, J. M. Widmier, S. Thompson, III,
J. B. Sangree, J. N. Bubb, and W. G. Hatlelid, 1977, Seismic stratigraphy
and global changes of sea level: in Payton, Charles E. (editor), Seismic
stratigraphy-Applications to hydrocarbon exploration: American Asso-
ciation of Petroleum Geologists Memoir 26, pp. 49-212.

Van der Voo, R., F. J. Mauk, and R. B. French, 1976, Permian-Triassic
continental configurations and the origin of the Gulf of Mexico: Geology,
vol. 4, pp. 177-180.

Walper, Jack L., and C. L. Rowett, 1972, Plate tectonics and the origin of
the Caribbean and the Gulf of Mexico: Gulf Coast Association of
Geological Societies Transactions, vol. 22, pp. 105-116.

INFORMATION CIRCULAR NO. 98

AUTHOR INDEX

Addington, J. W........................37
Anderson, Thomas H................ 19
Andress, Noel E.......................2, 9
Applegate, Albert V..................2.
Applin, Esther R.......................3.
Applin, Paul L...................... 2, 3
Arden, Daniel D., Jr................... 3
Ball, M. M.................................20
Banks, J. E...............................4.
Barnett, Richard S.................... 4
Bass, Manuel N........................5.
Beall, Robert.............................20
Behrendt, John C.....................21
Berdan, Jean M................... 5, 14
Bridge, Josiah...........................5
Brown, Flett J...........................13
Bryan, G. M.............................14
Buffler, Richard T...............22, 28
Campbell, R. B..........................6
Carroll, Dorothy.......................... 6
Carye, J....................................28
Cavanaugh, T. D......................27
Chowns, T. M.............................. 7
Cole, W. Storrs......................... 8
Coney, Peter J....................... 24
Cramer, Fritz H..................2, 8, 9
Crosby,. J. T..............................14
Daniels, David L.......................23
Dickinson, William R.................. 24
Dietz, Robert S.................. 25, 27
Dillon, William D...........25, 26, 29
Drake, C. L......................... 16, 26
Freeland, George L..................27
French, R. B...............................33
Goldstein, Robert F................. 2, 9
Grasty, Robert......................9, 12
Griffin, George M....................... 9
Hall, D. J................................ 27
Harrison, C. G. A..................... 20
Heirtzler, J................................ 26
Henk, F. H., Jr......................... 34
Hennion, J.............................. 16
Hirshman, J............................ 26
Holden, John C........................ 25
Horton, J. Wright, Jr..................28

Ibrahim, Abou-Bakr K................28
King, Elizabeth R................... 10
Klitgord, Kim D...................10, 29
Krivoy, Harold L..................... 11
Kriz, Jiri..................................... 14
Ladd, John W..........................30
Latham G...................................28
Loudon, E. J.............................34
Lynts, George W......................30
Mauk, F. J................................ 33
McMillen, K. J.............................27
Milton, Charles...................11, 12
Mitchum, R. M., Jr................. 33
Mueller, Paul A.........................12
Mullins, Henry T.......................30
Nafe, J. E................................. 16
Neathery, Thornton L................. 28
Odom, A. Leroy........................13
Osburn, William L.....................32
Palacas, James G....................2
Paul, Charles K........................25
Pilger, Rex H., Jr...............13, 31
Pojeta, John, Jr........................14
Popenoe, Peter............0, 23, 29
Porch, Jon W......................... 12
Pratt, Richard W.......................9
Pyle, Thomas E........................11
Raschilla, S. N.......................... 34
Reel, David A...............................9
Robb, James M........................21
Rowett, C. L............................. 35
Schlee, John.............................21
Schmidt, Victor A................... 19
Schouten, Hans........................ 10
Shaub, Jeanne F......................22
Sheridan, Robert E........14, 16, 32
Silverstein, Katherine M.............21
Smith, Douglas M..........16, 17, 18
Sougy, Jean M. A...................... 26
Sproll, Walter P........................ 25
Stoffa, P. L............................... 14
Tanner, William F.....................33
Todd, R. G............................... 33
Uchupi, Elazar............................ 28
Van der Voo, R........................33

BUREAU OF GEOLOGY

Walper, Jack L.......17, 34, 35, 36
Watkins, Joel S..................22, 27
Wicker, Russell A.....................18
Williams, C. T...........................7.
Wilson, Gary V.........................19
Wilson, J. Tuzo.................... 9, 36

Winston, George O...................... 2
Wood, Michael L...................... 36
Woods, R. D...............................37
Worzel, J. Lamar.....................22
Zeitz, Isadore....................... 23, 28

INFORMATION CIRCULAR NO. 98

SUBJECT INDEX

Subject

Author(s), Date

Page

Florida Basement Geology:
age determinations Andress, et al. 1969.................................... 2
Bass, 1969................................................ 5
Campbell, 1939................................ ........... 6
Cole, 1944..................................... ............. 8
Cramer, 1973............................. ............. 8
Grasty and Wilson, 1967................................. 9
M ilton, 1972................................. ............. 11
Milton and Grasty, 1969.................................12
Odom and Brown, 1972.................................13
Sm ith, 1982................................... ........... 17

deep well data

geochemistry

geophysical data

heavy mineral
analysis
paleogeography

Applin, 1951 ................................... ........... 2
Applin and Applin, 1965................................. 3
Barnett, 1975................................ ............ 4
Campbell, 1939...................................... ........... 6
Campbell, 1940............................... ........... 6
Cole, 1944....................................... ............. 8
Goldstein and Cramer, 1969..........................9
Grasty and Wilson, 1967................................. 9
Milton, 1972................................. ............. 11
Milton and Grasty, 1969................................. 12
Carroll, 1963................................... ............ 6
Milton, 1972................................. ............. 11
Milton and Grasty, 1969................................. 12
Mueller and Porch, 1983................................ 12
Arden, 1974................................... ........... 3
Griffin, et al., 1977....................................... 9
King, 1959.................................. .......... .. 10
Krivoy, 1972..............................................11
Sheridan, et al., 1981.....................................14
Sheridan, et al., 1966.....................................16
Smith, 1982............................................... 17
Wicker and Smith, 1978.................................18
Wilson, 1975................................. ............ 19

Carroll, 1963................................... ............ 6
Applin, 1951.................................. ............ 2
Barnett, 1975................................. ........... 4

BUREAU OF GEOLOGY

Author(s) Date

paleontology

petrography

petroleum
potential

review

stratigraphy

Bass, 1969....................................................... 5
Campbell, 1940................................ ........... 6
Chowns and Williams, 1983............................ 7
Cramer, 1971................................... ............ 8
Cramer, 1973................................ ............ 8
Klitgord, et al., 1984....................................... 10
Odom and Brown, 1976................................. 13
Pilger, 1980................................... ........... 13
Sheridan, et al., 1981.....................................14
Sheridan, et al., 1966.....................................16
Smith, 1983................................... ........... 16
Smith, 1982................................... ........... 17
Wicker and Smith, 1978.................................18

Andress, et al. 1969....................................... 2
Cole, 1944..................................... ............. 8
Cramer, 1971................................... ............ 8
Cramer, 1973................................. ............. 8
Goldstein and Cramer, 1969..........................9
Pojeta, et al., 1976......................................... 14
Smith, 1982................................... .......... 17

Bass, 1969................................. ...............5
Carroll, 1963................................... ............ 6
Milton, 1972................................. ............. 11
Milton and Grasty, 1969...................................12

Applegate, et al., 1981................................... 2
Arden, 1974................................... ........... 3
Banks, 1974................................... ........... 4

Barnett, 1975................................. ........... 4
Smith, 1982................................... ........... 17

Applegate, et al., 1981................................... 2
Applin and Applin, 1965................................. 3
Bridge and Berdan, 1951...............................5
Carroll, 1963................................... ............ 6
Cole, 1944.......................................................... 8
Goldstein and Cramer, 1969..........................9
Pojeta, et al., 1976......................................... 14

Subject

Page

INFORMATION CIRCULAR NO. 98 45

Subject Author(s) Date, Page

structure Applin and Applin, 1965................................. 3
Arden, 1974................................... ........... 3
Banks, 1974................................... ........... 4
Barnett, 1975................................ ............ 4
Bridge and Berdan, 1951............................... 5
Chowns and Williams, 1983............................ 7
King, 1959................................... ........... .. 10
Klitgord, et al., 1984.......................................10
Krivoy, 1972..............................................11
Sheridan, et al., 1981.....................................14
Sheridan, et al., 1966.....................................16
Sm ith, 1983.................................. ............ 16
Sm ith, 1982................................... .......... 17
Wicker and Smith, 1977.................................18
W ilson, 1975................................. ............ 19

tectonics Barnett, 1975................................. ........... 4
Chowns and Williams, 1983............................ 7
Cram er, 1971................................... ........... 8
Grasty and Wilson, 1967................................. 9
King, 1959.................................. .......... .. 10
Klitgord, et al., 1984.......................................10
Krivoy, 1972..............................................11
Odom and Brown, 1976................................. 13
Pilger, 1980................................... ........... 13
Mueller and Porch, 1983................................12
Sheridan, et al., 1981.....................................14
Sheridan, et al., 1966.....................................16
Sm ith, 1983................................... ........... 16
Sm ith, 1982................................... ........... 17
W alper, 1974................................ ............ 17

Related Regional and Tectonic Studies:

Bahama platform Dietz, et al., 1970................................... ..25
Freeland and Dietz, 1971............................ 27
Mullins and Lynts, 1977...................................30
Sheridan and Osburn, 1975...........................32

breakup of
pangaea Anderson and Schmidt, 1983........................ 19
Ball and Harrison, 1969............................... 20
Dietz, et al., 1970........................................ 25
Freeland and Dietz, 1971............................ 27
Klitgord, et al., 1983.......................................29

Subject

Caribbean

geophysical data

Gulf Coast basin

Gulf of Mexico

BUREAU OF GEOLOGY

Author(s) Date, Page
Ladd, 1976...............................................30
Mullins and Lynts, 1977................................. 30
Pilger, 1978..................................................... 31
Walper, 1980................................. .......... 34
Walper, et al., 1979........................................35
Walper and Rowett, 1972.............................. 35
Wilson, 1966.............................................36
Wood and Walper, 1974................................ 36
Woods and Addington, 1973....................... 37

Anderson and Schmidt, 1983...................... 19
Ball and Harrison, 1969.................................20
Freeland and Dietz, 1971............................ 27
Ladd, 1976................................................30

Behrendt, et al., 1974.................................... 21
Buffler, et al. 1980..........................................22
Daniels, et al., 1983....................................... 23
Dillon and Paul, 1982.....................................25
Drake, et al., 1963......................................... 26
Hall, et al., 1982........................................... 27
Horton, et al. 1984....................................... 28
Ibrahim, et al., 1981....................................... 28
Ibrahim, et al., 1982....................................... 28
Klitgord, et al., 1983.......................................29
Ladd, 1976....................................................30
Sheridan and Osburn, 1975...........................32
Todd and Mitchum, 1975............................... 33

Beall, 1973................................................20
Wood and Walper, 1974................................ 36
Woods and Addington, 1973....................... 37

Anderson and Schmidt, 1983...................... 19
Ball and Harrison, 1969............................... 20
Beall, 1973................................................20
Buffler, et al., 1980.........................................22
Dickinson and Coney, 1980...........................24
Hall, et al., 1982..................................... ..27
Ibrahim, et al. 1981........................................ 28
Ibrahim, et al., 1982....................................... 28
Pilger, 1978...................................................... 31
Tanner, 1965................................. .......... 33
Todd and Mitchum, 1975............................... 33

INFORMATION CIRCULAR NO. 98

Author(s) Date

opening of the
North Atlantic
Ocean

petroleum
potential

pre-Atlantic
Ocean
reconstruction

southeastern United
States Coastal
Plain

stratigraphy

structure

Van der Voo, 1976.........................................33
Walper, 1980........................................... 34
Walper, et al., 1979........................................35
Walper and Rowett, 1972.............................. 35
Wood and Walper, 1974................................36

Behrendt, et al., 1974.................................... 21
Dickinson and Coney, 1980...........................24
Dietz, et al., 1970................................... ... 25
Ladd, 1976................................................30
Pilger, 1978................................... ............ 31
Wilson, 1966.............................................36

Dillon and Paul, 1982.....................................25
Sheridanvand Osburn, 1975............................. 32
Woods and Addington, 1973....................... 37

Anderson and Schmidt, 1983...................... 19
Behrendt, et al., 1974.................................... 21
Dickinson and Coney, 1980.............................24
Dietz, et al., 1970................................... ..25
Freeland and Dietz, 1971............................ 27
Klitgord, et al., 1983.......................................29
Mullins and Lynts, 1977.................................30
Pilger, 1978...................................................... 31
Van der Voo, et al., 1976............................ 33
Walper, 1980................................ ............ 34
Walper and Rowett, 1972.............................. 35
Wilson, 1966..............................................36

Daniels, et al., 1983......................................... 23
Horton, et al., 1984..................................... 28
Klitgord, et al., 1983.......................................29

Dillon and Paul, 1982.......... ............................25
Todd and Mitchum, 1975...............................33

Behrendt, et al., 1974...................................... 21
Daniels, et al., 1983......................................... 23

Subject

Page

BUREAU OF GEOLOGY

Subject

Author(s), Date Page
Dillon and Paul, 1982.....................................25
Drake, et al., 1963......................................... 26
Horton, et al., 1984...................................... 28
Ibrahim, et al., 1981....................................... 28
Klitgord, et al., 1983.......................................29

Behrendt, et al., 1974.................................... 21
Dillon and Sougy, 1983..................................26
Todd and Mitchum, 1975............................... 33

West Africa

INFORMATION CIRCULAR NO. 98

APPENDIX

FLORIDA DEEP WELL DATA

Well location maps are available from the Florida Geological Survey.

FLORIDA DEEP WELL DATA
(Prinmrlly wells which penetrlaed basement, bul Includlng somve ignfllcant wells which did not)

Welli and
County Permit No.
Alachua W-1486
P.49

W.1472
P-562

W-1487
P-4

W-11447
P.536

W.12226
P-700

Baker W-1500
P-59

Bay W.12498
P-690
W.14844
P-1010

Bradford W-1466
P-41

W-10798
P-465

Calhoun W-12812
P-777

Well Name
Tidewater Assoc.
Oil Co.-R.H.
Cato No. 1

Tidewater Assoo.
011 Co.-J.A.
Phlfer No, 1

Tidewater Asoo.
Oil Co.-Josle
Parker No. 1

Chevron-Container
Corp. 1

Chevron-
Donaldeon 1

Hunt Oil Co.-
H. L Hunt No, 1

Charter Expl. 2-
St. Joe Paper Co.

Houston 011 &
Mlnerals-SW
Forest Industries
13-3 No. 1

Tidewater Assoc.
Oil Co.-M,F.
WIggins No. 1

Inexoo 011 Co.
Gilman Paper

Mallard Explora-
tion Inc.-
Intemational
Paper Co. 31-2

Co

implellon Elev. of Total Depth Type of Baement
Date Well8, ft. of Well, ft. Reference Rook Encountered
1947 112 3150 Applln, 1951 quartatlic sandstone
& shale, PaleozolO

1947 132 3228 Applln, 1951 quartzltic sandstone
& shale, Paleozoic

1947 188 3220 Applln, 1951 quartltic sandstone
& shale, Paleozolo

Location
Sec. 23
TA8 RISE

Sec. 24
T98 R21E

See. 33
T78 R19E

Seo. 7
TBS R21E

Sec. 34
T8S R21E

Sec. 21
T1N R20E

Sec. 27
TIS R17W

Sec. 13
T28 R12W

Sec.15
TOS R20E

Sec. 22
T45S R22E

Sec. 31
T1S RIOW

2861

3340

3349

12313

12486

Barnett, 1975

Bamett, 1976

Applln, 1951

Barnett, 1975

Ordoviolan quartzite;
no volcanic.

Ordoviclan quartzite;
no volcanioa

Paleozolo quartzltlo
sandstone

granite

No published
Information.

1947 141 3167 Applln, 1951 Quartltic sandstone
& shale, Paleozolo

1970 148 3154 Bamett, 1975 Paleozolc quartztio
sandstone

1976

12140

3140/27

2964/170

No published
Information.

1. Florida Bureau of Geology well number.
2. Unless otherwise Indloated, these are drill floor elevations (In feet above MSL).

Depth to and
Penetration
of Basement, ft. Comments
3135/15

3217/11

3170/50

2600/255

3314/26

3342/7

12256/55

1972

1974

1947

1973

1980

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but Including some significant wells which did not)

Well1 and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Charlotte W-979 Humble 011i & Re- Sec. 17
P-6B fining Co.- T428 R23E
Lowndes-Treadwell
No. iA

W-8139 Mobile Oil 1 -

1945 20

S2320'28"W 1967

P-375 State Lease 224B 42,424' from
USGS Eng-
lewood

W-10717 Exchange O&G 1- Sec. 7
P-459 Payson T418 R27E

Citrus W-7534 Mobil 011 1 Sec. 12
P-358 Camp Phosphate T178 R18E

W-7538 Mobil 011 1- Sec. 25
P-353 Harbond T178 R18E

W-7543 Mobll 011 1 Sec. 8
P-350 Garby T198 R17E
W-8304 Mobil Oil Ai 2850'00"N
P-382 State Lease 224A 82'49'42"W

Clay W-1590 Humble Oil & Re. Sec. 4
P-50 fining Co. Fore- T6S R25E
most Properties
Corp. No. 1

Collier W-961 Humble Oil & Re. Sec. 30
No permit finlng Co, Gulf T48S R30E
Coast Realities
Corp. No. 2

1970

1965

1965

1965

1967

1947

Total Depth
of Well, ft.

13304

Reference

Type of Basement
Rock Encountered

Applln, 1951

64 12931 Bamett, 1975 pseudospherulitic

64 12931 Barnett, 1975 pseudospherulltic
granophyre

80 13432 Bamett, 1975

4490

4794

5556

6041

5862

1944 34

Barnett, 1975

Barnett, 1975

Bamett, 1975

Bamett, 1975

Applln, 1951

13512 Applln, 1951

Paleozoic quartzitlo
sandstone; no volcanlcs

Paleozoic quartzltic
sandstone; no volcanic

Paleozolo quartzltic
sandstone; no volcanic

quartzitlo sandstone

Paleozolo quartzitlc
sandstone

Depth to and
Penetration
of Basement, ft. Comments
Did not reach
basement; TD In
Lower Cretaceous.

12877/54 170 4 my (Mobil).

Did not reach
basement; TD In upper
part basal clastic
section, L Cret.

4430/60

4738/56

5520/36

6886/34

3725/2137

Devonian (Mobil
paleo).

Did not reach base-
ment; TD In Lower
Cretaceous.

Bass Enterprises Sec. 12
Prod. Co. Collier T52S R27E
Co. 12-2

Exxon, Collier Co. Sec. 20
Well No. 20-2 T48S R30E

1975 (KB)30 18670 Applegate, et, Igneous rock
al., 1981

1981 45 17200

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL),

W-12838
P-778

W.15122
P-1042

18810/60

No published Infor-
mation.

,I

FL.OID[)A OEP WELL DAFA
(Pliimarily will whiluhi p(rwuiltatd tb awrniirl, but including somi biurnlif;unl welle which did nol)

Well' and
County Permit No. Well Name

Completion Elev. of
Location Date Well1, ft.

Total Depth
of Well, t.

Reference

Depth to and
Type of Baemnenl Penetration
Rock Encountered of Baement, ft. Comments

Columbia W-1789 Humble Oil & Re.
P-77 fining Co, J.P.
Cone No. 1

Seo. 22
T1N R17E

1948 141 4444 Applln, 1851 Weathered zone;

3482/10

Paleozoic black shale; 3492/952

diabase and amygdular
basalt sills encountered
In the black shale

W-1832 Sun Oil Co. Sec. 24
P-93 M. W. Sapp No. 1A T28 R1IE

W-1915A Sun Oil Co.- Sec. 27
P-104 W, F, Johnson No. T4S RISE
1

W.1923 Sun Oil Co. Se. 11
P-107 Clarence Loyd No. T5S R17E
1

W-1981 Sun Oil Co, -
P-111 Ruth M. Bishop
No, 1

Sec. 10
T48 R17E

W-2164 Gulf O11 Corp. Sec. 2
P.124 Kle Vlning No, 1 T48 R16E

W.8585 Richard C. Bradley Sec. 25
P-399 1 J. M. Carter T6S R1SE

W.8586 Richard C. Bradley Sec. 18
P-390 1 Brunswick Pulp TOS R17E
& Paper

1948 138 3311 Applln, 1951 Paleozolc black shale

1949 87 3051 Applln, 1951 Paleozolo quartzltlc
sandstone

1949 124 2929 Applln, 1951 quartzitlo sandstone
& shale, Paleozolo

1949 174 2828 Applln, 1951 quartzltlc sandstone
& shale, Paleozoic

1950 117 3470 Bridge & Late Silurlan or
Berdan, 1951 Early Devonian
black shale

Goldstein, et Late Silurian or
al., 1989 Early Devonlan
black shale

1968 80 3115 Barnett, 1975 Paleozolo quartzltlc
sandstone, no volcanlce

3829/33
3584/1
4191/1
4193/2
4248/3
4287/3

3303/8

3033/18

2922/7

2813/15

Not studied petrographlcally,
Not studied petrographlcally,

not given Age estimate based
on fossil and lItho-
logic correlations

3350/?

3104/11

Sllurlan(?) chltlnozoans
recovered from sample:
3350-3460 ft.

1968 96 3097 Barnett, 1975 Paleozolo quartzltlo 3084/13
sandstone, no volcanic

W.11830 Getty Oil Co. 1 --
P-653 Holmes 21-8

Sec. 21
T38 R17E

1973 191 2898 Barnett, 1975 Paleozoic (Getty)

2848/42 Bamett did not
examine.

1, F!':a- Su t ,o Gec!Ogy woll number.
o i inlma ntharwiua Indielated. theme are drill floor elevatians fin feet above MSLI.

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but Including some significant wells which did not)

Well' and
Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft. Comments

W-11910 Getty Oil Co. 1 Seo 33
P-866 J. C. Marsh T28 R17E

W-14379 Shepherd Oil &
P-986 Gas, Inc. -
Shepherd-Rayonler
No, 1

Sec. 8
T4S RISE

W-889 Humble Oil & Re- Sec. 30
No permit fining Co. State T55S R36E
of Florida No. 1

DeSoto W-11766 Shell Oil 1 Sec. 22
P-609 Shell Punta Gorda T39S R27E

1973 157 3196 Barnett, 1975 Paleozoic (Getty)

3125/71

1979 194 3013

1945

15 11794 Applln, 1951

1972 (KB)77

1300 Barnett, 1975

Bamett did not
examine.

No published Infor-
mation.

Did not reach base-
ment; TD In Lower
Cretaceous.

Did not reach base-
ment; TD In basal
plastic section,
Lower Cretaceous.

W-12393
P-679,
679A

Amoco Prod. 1 Sec, 19

Opal Knight

T388 R27E

Dixie W-1114 Stanollnd Oil & Sect. 5
P-11 Gas Co. & Sun Oil T118 R11E
Co. Perpetual
Forest, Inc. No. 1

W-1405 Sun Oil Co. -
P-36 Hazel Langston
No, 1

W-1863 Sun Oil Co. -
P-97 P. C. Crapps "A"
Well No. 1

Sec. 8
T8S R14E

Sec. 36
TSS R10E

1974 119 11655 Barnett, 1975 Jurassic diabase,

resembling Polk &
Hardee County wells

1946 33 7510 Applln, 1951 Paleozolo quartzltic
sandstone

1946 33 3671 Applln, 1951 quartzltic sandstone &
shale, Paleozolo

11627/28

5228/2282

3645/26

1949 41 5104 Applln, 1951 Paleozolc sandstone & 5016/88
shale

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

County

Dade

FLORIDA DEEP WELL DATA
(Primaily wells which penetrated basement but Including eome significant welt which did not)

Well and
County Permit No. Wel Name

Completion Elev of
Location Date Well, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to nd
Penetraton
of Basement, ft. Comments

Duval

W-8881 T. A. Durham 1 -- c. 23
P.402 Monticelo Drug T18 R25E

W.-89 T, A. Durham 61 -Sec. 17
P-410 Oilman Paper T38 R23E

W.10392 T.A. Durham 1 84c. 11
P-404 OIlman Paper T38 R23E

Eseembla W.15013 Chevron USA Inc. -Sec. 2
P.1027 La Floresta Well T3N R33W
No. 2-1

Flagler W-1473 Humble Oil & Re- Sec. 8
P-44 fining Co. J. W. T118 R28E
Campbell No. 1

1969 91 4192
jogger )
4250
(Barmett)

Bamnet, 1975 Paleooac; no voicanke 4151/41 Penetraton using
logge's TD.
4151/99 Penetraton using
Bamntris TD.

1969 94 3521 Baeatt, 1975 Pleowzoi quartlic 3456/3
sandstone; no voeanice
1909 95 3743 Barnet, 1975 Paleozoic quartist 3637/106
sandstone; no volcano
1981 256 17950

1947 31 4632 Applin, 1951 tuff & volcanic
agglomerate of rhyolUtc
composition

Basn, 1969 tuff, richer In CaO
than rhyodte

Franklin W-487 Mobll Prod. 1C N4203'47"E
P-387 State Lease 224A 121,639.31' from
Tr-Statlon St.
George lighthouse

Gllchrit W-1003 Sun 01 Co. Sec. 15
P-5 Alto Adame No. 1 T9S RISE

W.1819 Sun Oil Co. -
P-89 Wllllame Bros.
No. 1

Sec. 12
TSS R15E

No published Infor.
matlon.

4588/44 MIxed tuff derived
from Ignous complex.
Orgin sedimentary
or explove Igneous.

(Bass examined Mineral comp. Indl-
core from this cate incomplete
lower Interval; dj. to condition
exact depth un- of greenchit
known due to face.
mislabeing.)

1973 37 (Baett) 14824 Barnett, 1975 Eagle Mills Fm. 13850/434 Penetration using
(Subeequently original TD of 14,284.
drilled to First diabase sll 13926/37 No Informallon
14369) published on sub
aequent drilling.

1946 93 3753 Applin, 1951 quartitc sandstone
& shale, Paleozoic

1948 77 3348 Applin, 1951 quarztlc sandstone
& shale, Paleozoic

3588/165

3348/18

1. Florida Bureau of Geology well number.
:. ', .. ,_ .. .,' 5 are dr:l f rar o:evatlcns (In feet above MSL).

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but Including some significant wells which did not)

Well1 and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft. Comments

Gulf W-12483 Charter Expl. & Sec. 26
P-870 Prod. 1 St. Joe TBS R1OW
Paper Co.

W-12509 Hunt 011 30-4- Sec. 30
P-748 International T3S R11W
Paper

W-12617 Charter Expl. Sec. 12
P-762 Prod. 6 St. Joe TSS R10W
Paper Co.

W-14173 Mesa Petroleum- Sec. 29
P-957 St Joe Paper Co. TBS R9W
29-4 Well No. 1 -

Hardee W-1655 Humble Oil & Re- Sec. 23
P-62 fining Co. T35S R23E
B. T. Keen No. 1

1973 34 14297 Bamett, 1975 dacte porphry (ash
fall tuff, red brown,
massive appearance)

1974 81 13284 Barnett, 1975 granodlorite, Late
Precambrian or Early
Cambrian?

Krueger Enter-
prises, 19813

1975 22 14574 Barnett, 1975 Upper Paleozolc or
Lower Trlassic

1980 47 14186

1948 83 11934 Applln, 1951 Lava & pyroclastc
rocks
Bass, 1969 basalt

14261/36

12988/386

core: 14261-14297
oblique fractures:
14264 & 14267.

12,950-12990:709 25my,
K-Ar age determined from
feldspar concentrate

14499/75 Coarse quartltic as
with Othic & felds-
pathic fragments,
orange claystone &
red shale. Weathered
zone at top.

No published
Information.

11828/106

(Bass ex-
amined core
from 11930-
11932)

Milton &
Grasty, 1969

Least altered of
volcanic rocks
studied from
Florida.

11,853; whole rock K-Ar
age determinations:
143 t 7 my, 147 t 3 my

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL),
3. Unpublished age determination (memo on file at Fla. Bureau of Geology); material submitted by H. Kelley Brooks to Krueger Enterprises, Inc., Geochron Laboratories Division.

FLORIDA DEEP WEL. DATA
(Primarily wells which penetrated basement, but including0 ome significant wells which did nol)

Wellt and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, Ft.

Total Depth Type of Pasement
of Well, ft. Reference Rock Enoountered

Depth to and
Penetration
of Baement, Ft. Comments

Hendry W-11504 Phlllpe 10 -
P-66B Seminole Tribe

Sec. 26
T485 R33E

W.12690 Shell Oil Company Sec. 19
P.766 1 Aloo Land & T458 R32E
Dev.

Hemando W.994 Ohio O11 Co. -
P-1 Hemasco Corp.
No. 1

8ec. 19
T238 R16E

W.8188 S. Davis & G. Sec. 32
P-378 Thayer 2 Hill T22S R21E

W-8533 S. Davis & G. Sec. 11
P-391 Thayer 1 Davis T23S R20E

Highlands W-966 Humble OIl & Re- Sec. 34
P-B-1 fining Co. C.C. T38S R29E
Carton Estate No.
1

1972 (KB)36 17028 Barnett, 1976 tuffaceous detritus
(7 se comments)

1975 44 16000 Applegate, et
al., 1961

1946 47 8472 Applln, 1951 Paleozolo quartzltli
sandatone

1986 82

6209 Barnett, 1975 quartzttc sand-
stone; no volcanle

1968 151 6764 Barnett, 1975 quartzto sand-
stone; no volcanics

1948 114

12985 Applln, 1951 Anygdaloldal basalt,
rhyollte porphyry and
related volcanic rocks
Milton &
Grasty, 1969

TD In baal clatic
se ion, Low Cret.
top a 1682 (PhillNpe).
Exxon reports
tuffaceous detritue
In last samples.
Did not penetrate
basement, TD In
Wood River Fm.,
probably Late
Jurasalo.

7720/752

6190/19

8640/124

12618/367

12,664; whole rock K-Ar
age determination:
183 10 my

Continental Oil Sec. 20
Co. -C.C.Carl- T38SR28E
ton et al. Well No. 1
Amoco Prod. Co. Sec. 8
No. 1 Andrew T39S R30E
B. Jackson 6-2

1955 88 12630 Applin & Pre-Mesozooi
Applin, 1965 volcanic rocks

1977 25

12625

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

W-3578
P-225

W-13502
P-862

12602/2

No published Infor-
mation.

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but Including some significant wells which did not)

WellI and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetrason
of Basement, f. Comments

Hllsborough W-1005 Humble Oil & Re- Sec. 7
P.29 fining Co.- T. S. T31S R22E
Jameson No. 1

Holmes W-12199 Sonat Expl-Randall Sec. 32
P-716 Hughs T4N R17W

Indian River W-3783 Amerada PetroleumSec. 28
P.243 Corp. Fondren T318 R35E
Mitchell Well No. 1

1946 112 10129 Applin, 1951 rhyolite & volcanic
agglomerate

Bass, 1969 Intermediate to basic
composition

1974 140

1956 60

11201 Bamett, 1975 Eagle Mills fm. -
red arkosic sands &
granite wash.

Diabase, greenish
& weathered top

9488 Applln & Pre-Mesozolc
Applin, 1965 volcanic rocks.

10,010/119

(Bass examined Incomplete adj. to
core from conditions of
10,106-10,115) greenschist fades.

10240/861

10940

9410/78

Jackson W-1888 Humble Oil Re-
P-94 fining Co. -
C. W. Tindel No.

Sec. 8
T5N R11W

1949 128 9245 Applin, 1951 Paleozoic red & gray
sandstone & shale.

Two (Triassic?) basalt
sills In Paleozolo
strata.

Jefferson W-1854 Coastal Petroleum Sec. 1
P-95 Co. E. P. Larsh T2S R3E
No. 1

8890/42 Porphyritic homblende
basalt Intruive
or flow.
8970/13 Not studied petrographically.

1949 51 7913 Applln, 1951 Triassel (?) dlabase 7763/29
& related igneous rocks. 7850/40
(Sills or dikes In plastic
rocks of Triasslo (?) age.)

Paleozoic (?) quartztic 7909/4
sandstone.

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

8440/805

Well1 and
County Permit No. Well Name

W*10016 Amooo Prod. 1 -
P-486 Buckeye

Lafayette W-968 Sun Oil Co. -
P.4 P. C. Crappe No, 1

W-1890 Humble 011 & Re.
P-67 fining Co. -

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but including some significant wells which did not)

Completion Eiev, of Total Depth Type of Basement
Location Date Well, ft. of Well, ft. Reference Rock Enoountered

Sec. 17 1971 55 7034 Barnen, 1978 Eagle Mills fnm.
T28 R5E

Paleozolo sandstone.
Diabase.
Gabbrolo diabse.
Gabbrolo diabase.
e8, 25 1946 70 4133 Applln, 1951 quarUtzic aandstone &
TSS R12E hale, Paleozolo.

Sec. 20 1948 52 4235 Applln, 1951 quartzttlo sandstone &
T4S R11E hale, Paleozolo

R. L, Henderson No.
1

W-1860 Coastal Petroleum Sec.18 1949 45
P-100 Co. Ronald SappT6S R14E
No.1

W.2000 Glf 0il Corp. See. 36 1949 87
P-114 Brooks Scanlon T5S R10E
Inc., Block 49,
Well No. 1

No. W-no. Hunt Oil 1A P.C.Sec. 21 1974 74
P-725A Crappe T68 R13E

W-15078 Amoco Prod. Co. -Sec. 33 1981 82
P-1052 P. C. Crappe No. 1 T6S R11E

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL.)

3507 Applln, 1951 quartzltli sandstone &
shale, Paleozolc

4505 Applln, 1951 Paleozoic quartzltlc
sandstone.

5501

10078

Depth to and
Penetration
of BaSement, ft. Comments

6600/160

6748/288

8090/8
6730/13
6793/131

4030/103

4205/30

3480/27

4505/7

Barnett, 1975 Paleozolo shade & sand. 3716/1785
stone, no volcanics

No amnples available.

No published Infor-
mation.

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but including some significant wells which did not)

Depth to and
Well1 and Completion Elev. of Total Depth Type of Basement Penetration
County Permit No. Well Name Location Date Well2, ft. of Well, ft. Reference Rock Encountered of Basement, ft. Comments
Lake W-275 Oil Development Sec. 17 1937 120 6120 Applln, 1951 granite 6103/17

iiu permit o,. of Ia, J, I24a '25
SRay Arnold No. 1

W-11499 Hamilton Bros. 1 -Sec. 25
P-574 Keen T20S R26E

W-11771 Amoco Prod. 1 Sec. 5
P-629 Arnold Ind. T24S R25E

W-12891 Amoco Prod. 1 Sec. 29
P-795 USA 29-13 T16S R28E

W-10566 Humble 1 LehlghSec. 14
P-407 Acres T45S R27E

W-12293 Phillips Petr. Sec. 14
P-717 1 St. Joe A T28 R1E

Sun Oil Co. Sec. 31
J. T. Goethe T148 R17E
No. 1

Coastal Petroleum Sec. 16
Co. J. B. & J. T. T1SS R13E
Ragland No. 1

Levy W-1007
P-13

W-1537
P.66

1972

1972

1975

1970

1974

92

127

(KB)56

57

33

5397

5778

4894

15710

10486

Bamett, 1975

Bamett, 1975

Bamett, 1975

Bamett, 1975

weathered basic igneous 6195/202
rock

alaskite 5690/10
weathered Igneous 5747/31

altered quartz diabase

Eagle Mills fm,
Diabase sills

1946 34 3997 Applln, 1951 Paleozolc quartzltic
sandstone

1947 14 5850 Applln, 1951 Paleozolo black shale

15675/35

8450/2016
8488/88
9208/46
9316/5
9356/10
9380/2
9394/8
9430/29
10239/33

3960/37

No published Infor-
mation.

163 m.y. (Exxon)

5810/40

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL.)

Lee

Leon

FLORIDA DEEP WELL DATA
(Prnarily wells which penelraled basernenl, but Including borne snrulicant wells which did nol)

Well' and
County Permit No,
W-2012
P-105

Well Name
Humble Oil & Re-
fining Co. C. E.
Robinson No. 7

W-8305 Mobil Oil B -
P.383 State Lease 224A

Uberty W-12496 PlacId Oil 26-4
P.730 USA

W-12497
P-745

W-12739
P-769

Placid Oil 16.3
USA

Placid Oil 10-3
USA

Location

Sec. 19
T1i8 R17E

838'41'36"
45,733 ft
from USGS
"Lukens"

Sec. 26
T38 R5W

Sec. 16
T48 R6W

Sec. 10
T48 R7W

Madison W-1506 Hunt Ol Co. Sc. 68
No permit J. W. GIbson No. 2 T1S R1OE

W-1598 Hunt Oil Co. Sec. 5
No permit J. W. Gibson No. 4 T2S R11E

W-15017 Amoco Prod. Co.
P-1033 No. 1 Gllman
Paper Co.22-2

Sec. 22
T28 R9E

Completion
Date

1949

Elev. of
Well8, nft
so

Toe
of

1967 24

1974

Depth to and
lal Deplh Type of Basement Penetration
Well, t. Reference Rock Encountered of Basemenl, ft, Commenlt

4800 Applln, 1951 Decomposed Igneous rock4317/27 underlies L
Trisicl? basat 4344/33

Paleoolo-attered black 4377/0.5
shale
Paleozolo quartzltl 4377.6/231.5
sandstone

4735 Barnett, 1975 quartizti sandstone, 4595/140 Devonian (I
very fine grained, well paleo)
sorted, tight

62 12131 Barnett, 1975 Eagle Mills fm.
Diabae sills

1974 74 12400 Bamett, 1975 Altered granophyre

1975 75 12654 Bamett, 1975;
Applegate, el
al., 1981

1944 107 5385 Applln, 1951 Triaslc? diabase

1945

Paleozoio black shale

73 4096 Applin, 1951 Triassc? diabase
quartzltlc sandstone &
shale, Paleozolo

11753/378

12060/10
12095/36

12040/360

TD In Louann
(Jurasa o).

4589/39

4628/757

4044/16

4060/36

1981 114 10149

. Cret. ".

Mobile

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

Underiles L Cret
or older Meeozlc rock.

Underiles L Cret.
or older Mesozolc rock.

No published Infor.
naeton.

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but including some significant wells which did not)

Well1 and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft Comments

Manatee W.12691 Amoco Prod. 1 Sec. 35 1975 130 11500 Barnett, 1975 TO In basal elastic
P-759 St. Petersburg T33S R20E section, L Cret

Marion W-18 Ocala Oil Corp. Sec. 10 1928 80 6180 Applin & mica schist & quartzite, 4100/2080 Campbell, 1939, assigned
No permit No. 1 York T168 R20E Applin, 1944 age uncertain Jurassic age.
(Applln, 1951 refers
to this well as Paleozoic quartzltlc 4100?/2080? Cooke, 1945, gave a
Ocala 011 Corp. sandstone probable Paleozoic
Clark-Ray Johnson age.
No. 1)
W.901 J. S. Cobden Sec. 25 1928 195 4334 Applin, 1951 Paleozolo quartzltl 3660?/6747
No permit W. L Lawson No. 1 T138 R20E sandstone

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL.)

FLORIDA DEEP WELL DATA
(Primarly wells which penetrated basement, but Including nome sgnfricant wells whQh did not)

Well and
County Permit No. Well Name

Completion Elev. of
Location Date Wells, ft.

Tot Depth
of Well, ft.

Relerenoe

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, fl. Comments

Mad on, (oont) W.1482
P-63

Sun Oil Co. -
Henry N. Camp
No. 1

Se. 10
T188 R23E

1847 74 4037 Applln, 1981 Paleozolo (Lower
Ordovlolan) quaruttt
sandstone

Volcanic agglomerate or 4016/22
tuff of yollti oompo.
sltion

Base, 1900 quartzlt sandstone 4240360

volcano aggolmerate or 4615/22
tuff

W-1904 Sun 011 Co. -
P-101 H. T. Parker No.
1

1949 79 3845 Applln, 1951 Paleozolo quartztic
sandstone

Krueger Enter-
prises, 1981

3679/166

derived from an
Igneous omplex

Pogelble Cretaceoue
age for the quartl
zlo se & the
arkolo congl. &
s should not be
excluded In favor
of Paleoalo,
Arkoelo rooks are
kthologlaUly
different from those
of equv. age
elsewhere In Fla.;
therefore, a nearby
fault carp Is
poetuled, along
with a crystallne
eouroe east of the
wen.

3845': 424 15 my5
K-Ar age determined
from muscovite con-
centrale.

4240/376

Sec. 24
T148 R22E

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).
3. Unpublished age determination (memo on file at Fla. Bureau of Geology); material submitted by H. Kelley Brooke to Krueger Enterprises, Inc., Geochron Laboratores Division.

_ ____

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but including some significant wells which did not)

Well1 and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft. Comments

Martin W-14960 Kanaba Oi Sec. 21
P-1032 Corp. Allapattah T38S R39E
Properties 21-1

Monroe W-445 Peninsular Oil & Sec. 6
No permit Refining Co. T558 R34E
J. W. Cory No. 1

W-972 Gulf Oil Corp. Sec. 2
P-22 State of Fla. T67S R29E
Lease No. 373

Nassau W-336 St. Mary's River
No permit Oil Corp. -
Hilllard Turpen-
tne Co. No. 1

Sec.19
T4N R24E

W-10715 Amoco Prod. 2-1-TT Sec. 50
P-449 Rayonler T3N R27E

1981 44 13198

1939 14 10006 Applin, 1951

1947 23 15455 Applln, 1951

1940 110 4824 Applln &
Applln, 1944;
Applin, 1951

1970

No published infor-
mation.

Did not reach base-
ment; TD In Lower
Cret

Did not reach base-
ment; TD in
Jurassic(?).

Paleozolc black shale

Triasslc: Diabase sill
or dike

Cole, 1944 Triassic black shale
Igneous rock
Triassil diabase sill
or dike.

34 5489 Bamett, 1975 Paleozolo quartztic
sandstone
Triassic diabase sills

4640/168 The black shale has
been variously
4808/16 assigned Mlssisslpplan,
Pennsylvania, Triasslo
& Jurassic ages age
4840/155 still appears to be
4795/29 uncertain.

4808/16

5086/373
5260/15
5310/15
5418/51

Okaloosa W-11467 Sonat Expl. 1 -
P-590 J. G. Moore 3-11

Sec. 3
T3N R24W

1972 170 14514 Barnett, 1975 Eagle Mills fm 14095/419 14100-14480: quartztic
sandstone; 14480-14514:
Diabase (log Sonat) 14478 contact welded quartzite
& v. coarse diabase.

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

Well' and
County Permit No. Well Name

FLORIDA DEEP WELL DATA
(Prirmaly wells which peIntrated buement, but Including sorne sigrlficnl wells which did not)

Lompletlon Elev. of Total Depth Type of BaMsment
Location Date Well, ft. of Well, ft. Reference Rock Encountered

Depth to nd
Penetration
of Basemnt, ft. Comments

W*12301 Cabot Corp.
P-731 1-.-USA

W-14583
P-970

NoW.
number
P.1105

Okeechobee W-3739
P-237

W-12541
P-710

W-12542
P-732

Orange W-373
P-230

W-10778
P-441

Mettle Kelly Sims
at al. Trustees
No. 1

Tenneco Oil Co.,
USA-Fla. State
Lease 3229F, 31-3

Amerada Petroleum
Corp. Mare
Swanson No. 1

Shell Oil 1 -
Shell Soan 35-1

Shell Oil 1 -
Joan M. Davis

Warren Petroleum
Co. George Teny
No. 1

Texaco 1 Deseret
Farms

Sac. 9
T3N R26W

Sec.
T28 R22W

S8c. 31
T3N R26W

Sec. 6
T368 R34E

Sec. 35
T355 R26E

Sao. 9
T368 R35E

Sac. 21
T238 R31E

Sec.15
T238 R33E

1974 186 15250 Barnett, 1976 Eagle Mills fim

1980 26 14919

107 15362

1955 55 10838 Applln &
Applln, 1965

1974 60 11277 Bamett, 1975

1974 (KB)86 10767 Barnett, 1975

1955 100 6589 Applln &
Applln, 1965

1970 79 7119 Bamett, 1975

Pro-Meeozolc vol-
canic rocks

Weathered diabase

Weathered diabase

granophyric dacite
porphyry
granite

granite (Texaco,
Barnett did not examine)

15100/90 quorfltuo Con-
Wtainng broken
pebblea of quaMzte
a volani moral.

No published Infor-
mation.

No publohed Infor.
motion.

10750/88

11220/57

10642/103

10745/29

655039

Core ample. 10764
10772.67:101 : 15
m.y. (Rb/Sr from
feldpar by Sh1ll)

7070/49

1. Florida Bureau of Geology well number.
2. Unless otherwlee Indicated, these are drill floor elevations (In feet above MSL).

_____ __ __I_

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but including some significant wells which did not)

Well' and
Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft. Comments

W-1014 Humble Oil & Re-
P-8 fining Co. N.
Ray Carroll No. 1

Sec. 10
T278 R34E

1946 62 8049 Applln, 1951 altered & veined
blotite granite

8035/14

Bass, 1969 altered & veined (Bass examined Original rock had low
biotite granite core from 8042- temp. of cryst. induced
8044) by high water-vapor
pressure. Later
"cataeasis" &
hydrothermal alteration.
Age greater than 400
m.y. Is virtually
certain, probable age
of 530 m.y. Is supported
by ages from other
wells.

W-1411 Humble Oil & Re-
P-31 fining Co. W. P.
Hayman No. 1

W-11341 Atlantic Richfield
P-643 2 Bronsons Inc.

W-11342 Atlantic Richfield
P-539 1 Bronsons Inc.

Palm Beach W-1471 Humble Oil & Re-
P-47 fining Co. -
Tucson Corp. No. 1

W-12569 Shell 1 Gulf.
P-740 water 7.4

Sec. 12
T31S R33E

1946 86 8798 Applin, 1951 rhyolite

Milton &
Grasty, 1969

Sec. 24
T278 R29E

Sec. 3
T29S R31E

Sec. 35
T43S R40E

Sec. 7
T468 R35E

1972 78 6898 Bamett, 1975 granite

1972 86 7935 Bamett, 1975 granite

1947 34 13375 Applin, 1951

1975 30 16848 Bamett, 1975 igneous fragments in
Lower Cretaceous basal
elastic section
16710-16770

8740/68

8781: whole rock
K-Ar age determination
173 t 4 my

6840/58 Cuttings 6880-900:
biotite granite peg-
matte.

7890/45 Cuttings 7920-35:
biotite granite peg-
matite.
TD in Jurassic (?).

TD In lower part of
basal elastic section,
Lower Cret Top,
basal plastics of
16440.

1. Florida Bureau of Geology well number.
2. Unless otherwise indicated, these are drill floor elevations (In feet above MSL).

County

Osceola

FLORIDA DEEP WELL DATA
(Prjdniy wells wtih penevuted be emern but inc lding some igniflrWn wel which did rn)

Wel' and
County Permit No. Well Nae

Compltion Elev. of
Location Date Weol, ft.

otal Depth
of Well, ft.

Reference

Type otf Eeent
Rock Encoui eed

Depth o and
Pwntof on
of Bemenw, ft. Comments

Puoo W-1167 Atlantic Rchfleld Sec. 16
P-OBA 1 J. B. Starkey T268 R17

W-1239 Amoco Prod. Co. Sec. 8
P.743 1 Larkin Co. T258 R22E
8-4

W-12528 Amoco Prod. Co. Sec. 35
P-742 1 Cummer 35-3 T238 R22E

1973 (KB)66

9000 Barnett, 1975 TD n lower part of
beaal cleoa e sion,
Lowr Crne

1974 134 7148 Barnett, 1975 basal lastics

weathered augie
diabase (Jurassic)

1974 106

6496134
7129/19

6648 Barnett, 1975 granite, late Precambrian 6636/11
or Early Cambrian

W.13028 Hary A. Holton
P-875 No. 1 J. B.
Starkey 14.1

Sec. 14
T268 R17E

Plnellas W-160 Coastal Petroleum Sec. 7
P-75 Co. E. C. Wright TS30 R17E
No. 1

W-6278 Califomla Co. 3 28'05'3rN
P-304 State Lease 224B 82*2'50'W

Polk W-6741 Sun 0111 Sec. 19
P-403 Shepard Dairy T32S R27E
Putnam W-1514 Sun Oil Co. & Sec. 19
P-58 Seaboard Oil Co.- T19 R25E
0. Roberts No. 1A

1978 (KB)60 9333

1948 13 11607 Applin, 1951

1963

cusing 6640-46:
weathered & kollnited
bolle granite,
oaneM grained.

No pushed infrmn-
maton.

Did not reach bne
ment TD In Lower
Cretaceous.

Did not reach bae
meant TD in base
olatic scion,
Lower Creaceous.

57 10600 Bamett, 1975

1969 169

9670 Bamett, 1975 altered diabse
(Jurassic?)

9660/10

1947 206 3328 Applln, 1951 Paleozoic quaritict
sandstone

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevation (in feet above MSL).

_ ___ __

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but Including some significant walls which did not)

Wells and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft. Comments

W-1838 Sun O11 Co.- H.E. Sec. 37
P-96 Westbury et al. T11S R28E
No. I

W-11530
P-607

St. Johns W-10653
P-435A

Thayer & Davis
1 Johnson
Malphure
Carolina Resources
1 Cummer Co.

W-11084 Kerr McGee Corp.
P-506 1 H. W. Mizell

St. Lucie W-4323 Amerada Petroleum
P-259 Corp. Cowlas
Magazine No. 2

Sec. 27
T11S R27E

Sec. 70
T6S R29E

Sec. 35
T7S R28E

Sec. 19
T36S R40E

1949 32 3892 Applin, 1951 volcanic ash & tuff

Bass, 1969 Volcanic tuff &
agglomerate, mostly
rhyolltcl composition

1972 34 5572 Bamett, 1975 rhyolite (not examined)

1970 42 4850 Bamett, 1975 Paleozoic quartzltic
sandstone

1971 40 4583 Bamett, 1975 Paleozolc quartltic
sandstone

1957 32 12748 Applin & Pre-Mesozoic meta-
Applin, 1965 morphosed Igneous
Intrusive rocks

Bass, 1969 diabase

metam. rocks predom.
amphibolite

3873/19

3876/16 Mineralogy consistent
with metam. of green-
schist fades or
lower.

4426/1146

4830/20

4562/21

12680/68 12660-725: weathered
Igneous rock.

12734/approx.
10
12744/approx.
4

Milton, 1972

W-13082 Amoco 1 Peacock Sec. 26
P-772 Fruit and Cattle T36S R39E
26-1

1975

26 12652 Bamett, 1975

faulted against
overlying dlabase.
age, based on analysis
of blotttes 530 m.y.

Report of Age deter-
minations footnote 3.

no comments, had not
been completed.

-~ --
1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (in feet above MSL).
3. Age determination-Amerada Petroleum Corp. Cowles Magazine No. 1

_ __

Well' and
County Permit No. Well Name

FLORIDA PEEP WEI. DATA
(Prntmary wells which penetrated wbemen, but Including some Ignlticanl wells which did nol)

Completion Elev. of Total Depth Type of Ba emenl
Location Date Well, ft. of Well, t Reference Rock Encountered

Depth to and
Penetration
of Baserent, ft Comments

Santa Rou W-15381
P-1097

Suwannee W.1450
P.45

W.-148
P-57

W-1924,
1924A
P-100

Getty Oil Co. -
State Lease 2338
No. 1

Bun Oil Co. Ear
Odom No. 1

Sun Oil Co. J. H.
Tillll No.1

Sun Oil Co. A. B.
Russll

Sec. 1
T25 R28W

Sec. 31
T5S R15E

Sec. 28
T2S R15E

See. 8
T6SS R16E

Su 30 prjete

Spud
6/1983

1947

1947

1949

30 projected
to 17800

73 3161

162 3672

96 3139

Applln, 1961

Applln, 1961

Applin, 1951

Paleozolo black shale

Paleozolo black shale

Paleozolo qualzIft
sandatone

Depth
12734
12744

12748

ample
Material
Bausalt
Granite

S Chloritized blotite from schlst
and quartz dlortte gnelaa
S Plagloolase from quartz dlorite
gnelas
Diortte
S Homblende In diortte
(amphlbolite)

Analyst

Graety

BaUs

Grasty
Bass

Method

K.Ar

Sr/Sree

K-Ar

Age
89.3 2my
226 t6my
224 t3my
530 my

399 my
148 my

308 65 m.y.
470 m.y.
603 m.y.

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL)

3040/121

3600/72

3163/3

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but Including some significant wells which did not)

Well1 and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft. Comments

Suwannee,
(cont.) W.12246 Hunt Petr. 1 -
P-724 C. R. Howes

W-12247 Hunt Petr. 1 -
P-723 T. P. Hurst

Taylor W-1677 Humble Oil &
P-85 Refining Co. -
G. H. Hodges No.
1

W-2099 Gulf Oil Corp. -
P-116 Brooks Scanlon
Inc., Block 42
No. 1

W-2106 Gulf Oil Corp. -
P-119 Brooks Scanlon
Inc. Block 33
No. 1

Sec. 16
T2S R12E

Sec. 5
T3S R13E

Sec. 12
T5S RBE

Sec. 9
TBS R9E

Sec. 18
T4S R9E

1974 96 4520 Bamett, 1975 Paleozolc dark grey to
black shale

Paleozolo quartzltcl
sandstone

Paleozolo shale and
sandstone

qqartzltic sandstone &
shale, Paleozolo
1974 106 4496 Bamett, 1975 quartztic sandstone &
shale, Paleozolo
black micaceous shale,
Paleozolc

3726/284

4010/350

4360/150

4510/10

3640/390

4030/486

1948 36 6254 Applin, 1951 Triasel? basaltic rock 6153/12

Triasslo? diabase
gabbro

6165/89

1949 41 5438 Applln, 1951 Trlassic? diabase, prob. 5438/79
a lava flow

1950 96 5243 Applin, 1951 Trassic? diabase
gabbro

coarsely micaceous,
thin sa Interbeds.

fine-med, white-grey,
highly micaceous
streaks

red and brown stain.

greasy lustre, thin
sands zones, some
pyrttic streaks.

Underlies plastics of
Triase? or Jur? age.

underlies clastice of
Trass? or Jur? age.

5200/43 underlies clastics of
Triasm? or Jur? age.

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

Wll' and
County Permit No. Well Name

W*1001 Amoco Prod. 1 -
P-46 Canal Tbr. Co.

FLORIDA DEEP WELI DATA
(Primauly wells which penetrated basement, but Including some signltcen wells which did not)

Completion Eev. of Total Depth Type of Basement
Loation Date Well, ft. of Well, Reference Rock Enoountered

oe. 12 1970 82 7036 Barett, 197 Paleoiolo
T388 RE
Disbase

Depth to and
Penetration
of Basement, ft. Comments

86607/1182

6256/113
6417/247
67086/6

W-12697
P-774

W.12761
P-776

W.14718
P.1015

W.16445
P.1112

Union No W-No.
P-640

W.11870
P-60

W-11912
P-.80

Hunt Petr. 2 -
Buckeye Cellulose

Hunt Petr. 1 -
Bukeye Cellulose

Amooo Frances
Exnom 34-8 No. 1

Amoco Prod. Co. -
Bukeye Cellulose
7.4
Getty 011 1 -
K. 0, Dicks

Getty Oil 1 -
R. Billing 4-1

Getty Oil 1 -
W. Croft

Se. 34
T6s R18E

aea. 22
T78 R5E

STc. 34
T R2918E

SOc. 7

Sea. 31
T48 R19E

1975

1975

1980

1983

1973

1973

1973

7475

7503

6477

9000

3037

3015

3061

Barnett, 1975

Barnett, 1975 Paleozolc (Getty)

Barnett, 1975

Bamett, 1976 Paleozoic (Getty)

3029/6

No comments, had not
been completed.

No published Information.

No published Information.

No published Information.

No samples available.

No comments, samples
& logs not examined.

3046/15

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

I

I

FLORIDA DEEP WELL DATA
(Primarily wells which penetrated basement, but including some significant wells which did not)

Well1 and
County Permit No. Well Name

Completion Elev. of
Location Date Well2, ft.

Total Depth
of Well, ft.

Reference

Type of Basement
Rock Encountered

Depth to and
Penetration
of Basement, ft. Comments

Volusla W-1118 Sun Oil Co. -
P-19 Powell Land
Co. No. 1

Sec. 11
T178 R31E

1946 48 5958 Applln, 1951 Homblende dlorite.
Bass, 1969 Transported material
and/or weathered basement

Less weathered, cuttings
contain chlorlte &
plagloclase, some quartz
& no homblende.

quartz-bearing homblende
diorite.

hornblende diorite with
diabase-like texture.

homfels derived from
clayey volcanlc-quartzose
ss.
Milton &
Grasty, 1969

5910/48
5918/12 Base concludes that
Sthe diorite is
probably a sill and
5930/10 the country rock
meta-sedlmentary.
Total rock age: 480
my. The diorite
is older but not
5940/10 greater than 624 my
old. Horfela Is
prob. Precambrian
5950/5.5 or derived from a
sediment that was
derived from Prec.
5955.5/2.5 source.

5953-5954'; K-Ar: 480 my
(dated by H. Thomas,
R. Marvin, P. Elmore, &
H. Smith, USGS).

W-1746A Grace Drilling
P-78 Co. Retail
Lumber Co. No. 1

Sec. 2
T158 R30E

1949 44 5424 Applln, 1951 rhyolltic? volcanic rock 5403/21

Wakulla W-12114 Placid Oil Co. 1 Se. 27
P-696 USA Unit 27-2 T25 R3W

1973 99 OH 12242
STH 11747

Barnett, 1975 Eagle Mills fm.

Paleozolo grey-black shale 12200/20

Diabase sill,

1. Florida Bureau of Geology well number.
2. Unless otherwise Indicated, these are drill floor elevations (In feet above MSL).

11874/526

12220/22

mlcaceous, fissile

FLORIDA DEEP WELL DATA
(Pnmnrly w*el whdu peetrafted bawernt, but inckuOm some rglutrnt ~ *H4 wrhah did not)

Wel' and
County Pwmit No Wel Name

Completon Elev of
Location Date Wll, It

Total Depti
of Waed, t

Type of Baement
Reference Rock Encounleed

Deoh to and
Peneuabon
of B0r8aenl, t. Comment

Waton W-11182 Coaatal Prod. 1 Sec. 9
P-519 Brady Belcher T3N R21W

Wadon W-11374 Tex Gaa s Exl.
P-587 1. International
Paper Co.

Sec. 5
TSN R20W

W-11601 McCulloch 1 DS Sec. 24
P-612 Rudman 1 Indian T2N R1OW
Crk Ranch

W.12300 Charter O 4 -
P721 St. Joe Paper

Washington W-11398 R. Mosbacher et
P-549 al. 1 First Nat.
Bank of Akron

Sec. 31
T2 R20W

Sec. 20
TIN R15W

1971 214 12340 Barnet, 1975 Metmonrpvhoed volcanic
sandstone & granule con-
glomerate. Cambnan or
U. Precambrian.

1972 294 12028 Barnett, 1975 Eagle Mile fm.

Diabase lls

1972

140 11533 Barnett, 1975 Eagle Mill fm.

1974 43 14515 Barnett. 1975 granite

1972 (K8)128

11692 Bamen, 1975 Cambrian orU.
Precambrian met-
arkose & quarUite

12I2/55

11386/442

11610/30
11997/31
11422/111

Core 12333-12340: 3'
voice. granule congl.
a se, 3' lightly
metamorphosed red a
green sh, 1' pebble
congi. & a.

cutting at 11533:
very coare red s.

14480/35 cutting 14510-15:
oarse red granite
wash weathered
blowe granle
peomaftte.
11554/138 rhyolle, Arden,
1874.

W-11822 Rudman Resources Sec. 31
P-44 1 FNB of Akron T2N R15W
31-2

W-12347 Hunt Petr. -
P-738 Intenational
Paper Co.

Sec. 11
T4N R14W

1973

153 11593 Barnett, 1975 Cambrian or U.
Precambrian meta-
arkose & quarzte

1974 84 14044 Bamett 1975 Eagle Mils fm.

Late Paleozoi
Ordovician

11480/113

10760/180

10940/24
11180/2864

11200-300:
Sfphonocfmth cd.
tamosb JeAdns,
M. Ord. (Hunt plso).

1. Florida Bureau of Geology wen number.
2. Unless otherwise Indicated, these are drill floor elevations (in feet above MSL).

	Copyright
	Title Page
	Table of Contents
	Abstract
	Introduction
	Florida Basement Studies
	Related regional and tectonic...
	References
	Author index
	Subject index
	Appendix

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