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The Hawthorn Formation of northeastern Florida ( FGS: Report of investigation 94 )
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Permanent Link: http://ufdc.ufl.edu/UF00001281/00001
 Material Information
Title: The Hawthorn Formation of northeastern Florida ( FGS: Report of investigation 94 )
Series Title: ( FGS: Report of investigation 94 )
Physical Description: viii, 90 p. : ill., maps ; 23 cm.
Language: English
Creator: Scott, Thomas M
Scott, Thomas M
Davis, B. E ( Broderick E. )
Publisher: State of Florida, Dept. of Natural Resources, Division of Resource Management, Bureau of Geology
Place of Publication: Tallahassee
Publication Date: 1983
 Subjects
Subjects / Keywords: Geology -- Florida   ( lcsh )
Phosphate rock -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by Thomas M. Scott ... et al..
Bibliography: Includes bibliographies.
 Record Information
Source Institution: University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: aleph - 000541388
oclc - 10556389
notis - ACW4928
System ID: UF00001281:00001

Table of Contents
    Title Page
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        Page ii
    Letter of transmittal
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    Table of Contents
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    Part I. The geology of the Hawthorn formation of northeastern Florida
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    Part II. Characterization and beneficiation of the northeastern Florida phosphate-bearing Hawthorn formation
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    Copyright
        Copyright
Full Text










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

DIVISION OF RESOURCE MANAGEMENT
Casey J. Gluckman, Director

BUREAU OF GEOLOGY
C. W. Hendry, Jr., Chief










REPORT OF INVESTIGATION NO. 94

THE HAWTHORN FORMATION OF NORTHEASTERN FLORIDA

PART I-THE GEOLOGY OF THE HAWTHORN FORMATION
OF NORTHEASTERN FLORIDA

By
Thomas M. Scott
Florida Bureau of Geology

PART II-CHARACTERIZATION AND BENEFICIATION
OF THE NORTHEASTERN FLORIDA PHOSPHATE-BEARING
HAWTHORN FORMATION
By
B. E. Davis, G. V. Sullivan, and T. O. Llewellyn
U. S. Bureau of Mines, Tuscaloosa Research Center
Tuscaloosa, Alabama
1983


















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
August 15, 1983


Governor Bob Graham, Chairman
Florida Department of Natural Resources
Tallahassee, Florida 32301

Dear Governor Graham:

The Bureau of Geology, Division of Resource Management, Depart-
ment of Natural Resources, is publishing as its Report of Investigation
No. 94, "The Hawthorn Formation of Northeastern Florida.'

Part I discusses the geology of the Hawthorn Formation in north-
eastern Florida. Part II evaluates the phosphate content of the Hawthorn
Formation, and discusses beneficiation processes. This information
will aid in the wise development and use of this natural resource.

Respectfully yours,

Charles W. Hendry, Jr., Chief
Bureau of Geology



















































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

Tallahassee
1983








IV





























CONTENTS


Page
Part I -The Geology of the Hawthorn Formation of Northeastern Florida .......... vi
Part II-Characterization and Beneficiation of the Northeastern Florida
Phosphate-Bearing Hawthorn Formation ........................... 41























THE HAWTHORN FORMATION OF NORTHEASTERN FLORIDA


PART I

THE GEOLOGY OF THE HAWTHORN FORMATION OF
NORTHEASTERN FLORIDA

By
Thomas M. Scott
Florida Bureau of Geology
Tallahassee, Florida









TABLE OF CONTENTS

Page
Abstract ........................................... 1
Acknowledgements ................................................... 2
Introduction .................................................... 3
Purpose and Scope ........... ....................... .................. 3
M methods ................... .......... ................................ 3
Previous Work ...................... .. .............. ................... 4
OcalaGroup ................................................... 4
Hawthorn Formation ................... ............................ 5
Undifferentiated Post-Hawthorn Sediments .............................. 8
Lithologic Characteristics of the Hawthorn Formation ........................ 10
Stratigraphy ........................................................... 14
Geophysical Interpretation ................................... ......... 22
Structure ................ ............. ...... ........................ 24
Geologic History ........................................................ 29
Summary and Conclusions ............................................... 31
References ........................... ............................ 34
Appendix-Data forCores Used in This Study ................................ 37







































vii








ILLUSTRATIONS

Figure Page
1. StudyArea Location ......................................... 4
2. Percentage of Dolomite Units in the Hawthorn Formation ................... 13
3. Percentageof Sand Units in the Hawthorn Formation ..................... 15
4. Percentage of Clay Units in the Hawthorn Formation ....................... 16
5. Location of Cross-Sections ........................................... 17
6. Cross-SectionA-A' ................................................. 18
7. Cross-SectionB-B' ............ ............................. 19
8. Cross-Section C-C' ................................................ 20
9. Cross-SectionD-D' ................................................. 21
10. Typical Geophysical Log ............................................ 23
11. Structure Map of Ocala Group ........................................ 24
12. Features Expressed on Ocala Group Surface ............................. 25
13. Structure Map of Hawthorn Formation ................................. 27
14. Isopach Map of Hawthorn Formation .................................. 28



TABLE

Table
1 Nomenclature Chart ................................................... 6
















THE GEOLOGY OF THE HAWTHORN FORMATION
OF NORTHEASTERN FLORIDA

By
Thomas M. Scott

ABSTRACT

The Hawthorn Formation in northeastern Florida consists of widely
varying mixtures of clay, quartz sand, carbonate and phosphate.
Phosphate is virtually ubiquitous throughout the Hawthorn sediments
and occurs primarily as allochemical grains. The carbonate component
consists predominantly of dolomite. Limestone is generally less than 5
percent of the total Hawthorn carbonates. Clays are present in much of
the Hawthorn. Palygorskite and montmorillonite are the most common
clay minerals.
The Hawthorn Formation unconformably overlies the Upper Eocene
Ocala Group limestones. It is unconformably overlain by sediments
referred to as Post-Hawthorn Undifferentiated Sediments.
The stratigraphy of the Hawthorn is both complex and variable.
However, a generalized three-part subdivision of the Hawthorn is
recognized in northeastern Florida. In general, there is a basal dolomite
unit overlain by a sand and clay member (containing some dolomite)
which is, in turn, overlain by a dolomitic unit. A fourth unit is recognized
in the western part of the study area. This unit is a clayey, sandy,
phosphatic unit thought to be, at least in part, reworked.
The study area appears to have been affected by episodes of struc-
tural movement. Both minor warping and faulting are recognized.




2 BUREAU OF GEOLOGY


ACKNOWLEDGEMENTS

The author of this report would like to express his gratitude to the
staff of the Bureau of Geology for their assistance in drafting illustra-
tions, typing, proofing, and editing the manuscript. I gratefully
acknowledge the contribution of the staff geologists and graduate stu-
dent assistants for their suggestions and discussions during the
preparation of this report. The writer is grateful to the many private land-
owners who granted permission to drill stratigraphic core holes.
The author appreciates the assistance of the United States Bureau of
Mines in providing funding for core and data acquisition under contract
Grant Number G0166038.





REPORT OF INVESTIGATION NO. 94


INTRODUCTION
The Florida Bureau of Geology in cooperation with the U.S. Bureau of
Mines began to study the phosphate bearing sediments of the Haw-
thorn Formation in peninsular Florida in 1975. The first phase looked at
the phosphatic sediments in southwestern central Florida (Scott and
MacGill, 1981). The second phase, a continuation of the U.S. Bureau of
Mines grant (Grant Number G0166038), studied the Hawthorn Formation
in northeastern Florida. This report on the second phase presents the
results of a detailed lithostratigraphic study of the Hawthorn Formation
and of the overlying and underlying sediments.

PURPOSE AND SCOPE
The purpose of this study is to provide an understanding of the
geologic framework of the phosphatic Miocene Hawthorn Formation in
northeastern Florida and its relation to the overlying and underlying
units.
The Florida Bureau of Geology drilled 33 core holes in the study area.
These ranged from 140 to 500 feet (43 to 152 meters) in depth. Core data
obtained during this study were supplemented by water well cuttings
drilled prior to the investigation. All cores and cuttings are on perma-
nent file at the Bureau of Geology in Tallahassee. This data provided the
basis for construction of the geologic cross sections and structure and
isopach maps of the various geologic horizons throughout the area. The
study area includes 10 counties: Alachua, Baker, Bradford, Clay, Duval,
Flagler, Marion, Putnam, St. Johns and Union (figure 1).

METHODS
Thirty-three core holes were drilled in the study area utilizing a Failing
1500 Drill Master drill rig recovering 3 inch and 13/4 inch (7.6 and 4.4 cm)
cores. The core diametervaried with the type of tools required to sample
a particular interval. Washed samples of the post-Hawthorn sediments
were collected at 5 foot intervals. Continuous coring began at the top of
the Hawthorn Formation and continued into the Eocene limestones. All
cores from Bradford, Clay, Putnam and western St. Johns counties were
split and half sent to the U.S. Bureau of Mines in Tuscaloosa, Alabama
for chemical analysis. The remaining split is stored at the Florida
Bureau of Geology in Tallahassee. All core holes had gamma-ray logs
run to facilitate correlations. This information plus well locations and
total depth are listed in the Appendix.
The cores were examined by a geologist, described and then entered
into the Bureau's computer data files. The computer program is designed
to aid the geologist in the interpretation of lithologic parameters. Color
coded strip logs were constructed and correlated with the gamma-ray
logs. This aided in-the visual correlation between cores. The strip logs
and gamma-ray logs were then used to construct geologic cross sec-
tions. Samples were taken from the cores at various depths for x-ray
analysis to determine the dominant minerals present. The analysis was
done for both bulk samples and oriented clay samples.





BUREAU OF GEOLOGY


Figure 1. Study Area Location


PREVIOUS WORK

OCALA GROUP
The limestones presently incorporated in the Ocala Group were
originally placed in the Eocene by Conrad (1846). Smith (1881) correlated
the exposed limestones of Florida with the Vicksburg Limestone of
Mississippi and Alabama and applied that name to them. Dall and Harris
(1892) referred to these sediments as the Vicksburg Group. The term
Ocala Limestone was first used by Dall and Harris (1892) in reference to
the rock being quarried and best exposed near Ocala in Marion County.
Dall (1896) lumped the Eocene and the "Old Miocene" of Florida into the





REPORT OF INVESTIGATION NO.'94


Oligocene. Dall (1903) proposed the term "Peninsular Limestone" for
the lower division of the Vicksburg Group in the Florida peninsula.
Cooke (1915) discovered that the Ocala Limestone and the Peninsular
Limestone were identical and older than the Vicksburg Limestone. He
placed the Ocala Limestone back into the Eocene (Jackson Age). Applin
and Applin (1944) divided the Ocala Limestone into an upper and lower
member. Vernon (1951) restricted the Ocala Limestone to the upper
member of the Applins and referred to the "basal 80 feet of the Ocala
Limestone of Cooke (1945)" as the Moodys Branch Formation. Vernon's
Moodys Branch Formation was subdivided into the Williston Member
and the Inglis Member. Puri (1957) raised the Ocala Limestone to group
status and included three formations: the Crystal River, Williston, and
Inglis. The Florida Bureau of Geology currently accepts and uses Puri's
terminology (Table 1).



HAWTHORN FORMATION
The Hawthorn Formation was originally described by L. C. Johnson
(1888), who referred to the phosphatic beds in Alachua and Columbia
counties as the Waldo Formation. Dall and Harris (1892), using much of
Johnson's work, abandoned Johnson's Waldo Formation and described
the phosphatic beds as the "Hawthorne beds'.' Even though Dail did not
describe a type locality or use the term "formation;' later workers have
credited him for naming the Hawthorn Formation and describing the
type locality around Hawthorne, Alachua County. The Devil's Mill-
hopper, near Gainesville, as discussed by L. C. Johnson (1888), Dall and
Harris (1892), and Cooke (1945), and Brook's Sink in Bradford County, as
described by Cooke (1945), are accepted as cotype localities for the
Hawthorn Formation (Pirkle, 1956). Scott (1982) discusses the cotype
localities and equates them to cores taken nearby, designating the
cores as cotype cores for the Hawthorn Formation.
In 1909, Matson and Clapp designated Dall's "Hawthorne beds" as a
formation and considered it to be at least in part contemporaneous with
the Tampa and Chattahoochee formations. They included the
Hawthorn, Tampa, Chattahoochee and Alum Bluff formations in the
Apalachicola Group. Matson and Clapp's description did include some
limestone containing the echinoid Cassidulus sp. This limestone is
now referred to as the Suwannee Limestone.
Vaughan and Cooke (1914) correlated the Hawthorn Formation with
the Alum Bluff Formation in northwest Florida as defined by Matson
and Clapp (1909, p. 91) and suggested the name Hawthorn be dropped.
In later publications, Matson and otherauthors referred to the Hawthorn
Formation as the Alum Bluff Formation.
In 1929, Cooke and Mossom reinstated and redefined the Hawthorn
Formation to include Dall's (1892) "Hawthorne beds;' the Sopchoppy
Limestone and the Alum Bluff Formation of peninsular Florida as de-
fined by Matson and Clapp (1909). This new definition excluded the
Cassidulus-bearing limestone that had been described by Matson and
Clapp (1909).



















TABLE 1. Nomenclature of previous authors and this report

DALL & HARRIS (1892) MATSON & CLAPP(1909) COOKE (1945) PURI & VERNON (1964) THIS REPORT

PLEISTOCENE Sands Terrace and Coastal Terrace and Terrace deposits
Deposits Coastal Deposits Caloosahatchee beds
Undifferentiated
Post-Hawthorn
PLIOCENE Caloosahatchee Nashua and Caloosa. Caloosahatchee Sediments
beds hatchee beds and Citronelle Fms,

MIOCENE Newer
Miocene
Jacksonville Ls. Choctawhatchee Marl Duplln Marl Ft. Preston-Coarse Hawthorn Fm.
and Clastlcs
Older Jacksonville Fm. (Ls.) Hawthorn Fm.
Miocene Hawthorne

EOCENE Ocala Ls. e Hawthorne Fm. Ocala Ls. Ocala Group Ocala Group
(Nummulltic beds) g
S Ocala La.
S"Peninsular" Ls.






REPORT OF INVESTIGATION NO. 94


Very early in the nomenclatural history of the Hawthorn Formation it
was considered to be of "older Miocene" age by Dall and Harris (1892).
They observed the Hawthorn Formation in Alachua County lying uncon-
formably on rocks of supposed Vicksburg age and thought it contem-
poraneous with the Chipola Formation. A short while later, they altered
their concept of the Oligocene-Miocene boundary and positioned the
Tampa, Hawthorn, and Chipola formations, previously called "Older
Miocene',' in the Oligocene. Matson and Clapp (1909) continued this age
assignment, equating the Tampa and Chattahoochee formations in the
panhandle of Florida to the Hawthorn Formation.
Vaughan and Cooke (1914), in describing several sections.near White
Springs on the Suwannee River, thought the Hawthorn Formation was
contemporaneous with the Alum Bluff Formation. Faunal and strati-
graphic data formed the basis for their correlation.
Cooke (1945) correlated the Hawthorn Formation with the Chipola
Formation and parts of the Shoal River Formation in the Florida pan-
handle. He tentatively transferred some beds of Late Miocene age that
were previously included in the Hawthorn by Matson and Clapp (1909) to
the Duplin Marl. Cooke considered their contact unconformable and
postulated that the Hawthorn was deposited by an expanded Tampa sea
and that the Tampa/Hawthorn contact was conformable.
Pirkle (1956) studied the types of sediments in the Hawthorn Forma-
tion. He stated that the dominant sediment types found in the Hawthorn
in Alachua County include quartz sand, clay, carbonate and phosphate.
He further stated, "The proportions of these materials vary from bed to
bed and, in cases, even within a few feet both horizontally and vertically
in individual strata'.' Pirkle, et al., (1965) studied the Hawthorn sediments
in more detail paying particular attention to the heavy mineral suites.
Reynolds (1962), in studying the relationship of the Tampa-Hawthorn
sequence in peninsular Florida, identified lithosomes and used clay
mineralogy to conclude that the two formations interfingered. He iden-
tified a western carbonate lithosome (Tampa), an eastern plastic
lithosome (Hawthorn), and a central Florida shelf where these two
lithosomes interfingered. The carbonate lithosome contained a
palygorskite-montmorillonite-sepiolite suite, whereas the plastic
lithosome contained a montmorillonite-illite suite.
Espenshade and Spencer (1963) included all the phosphate bearing
sediments overlying older carbonate rocks in north Florida in the
Hawthorn Formation. This included the reworked phosphorites. They
divided the Hawthorn into an upper phosphorite unit and a lower
phosphatic dolomite unit.
Brooks (1966) proposed raising the Hawthorn to group status based
on the complex stratigraphy that has been discussed by many authors
(Pirkle, 1956; Espenshade and Spencer, 1963; Brooks, et al., 1966).
Brooks (1967) later reiterated this adding that the youngest formation
to be included in his Hawthorn "Group" would be the Bone Valley
Formation..
Sever, et. al., (1967) were able to divide the Hawthorn into four
recognizable lithologic units in the south Georgia-north Florida area.
They state, however, that all these units are not present over the
entire area.





BUREAU OF GEOLOGY


Puri and Vemon's (1964, p. 145) statement concerning the Hawthorn
expresses the feelings of many geologists. They state that the
Hawthorn Formation "... perhaps is the most misunderstood forma-
tional unit in the southeastern United States. It has been the dumping
ground for alluvial, terrestrial, marine, deltaic and pro-deltaic beds of
diverse lithologic units in Florida and Georgia that are stratigraphic
equivalents of the Alum Bluff Stage'
The north Florida phosphate district (as delineated by Williams, 1971)
includes the western part of the present study area. Williams (1971)
studied the phosphate deposits and included part of them in the
Hawthorn Formation.
Cooke (1945) divided the Miocene series into three different stages in
peninsular Florida: Early, Middle and Late. He believed that the age of
the Hawthorn Formation was Middle Miocene. In the past, this type of
definition has been general practice in defining both the age and bound-
aries of Florida formations. However, the lack of diagnostic data has
made it difficult to determine the exact age and boundaries of the for-
mations. As a result, the age assignment of the Hawthorn Formation
has varied considerably since its inception. Recent data indicates that
the deposition of the Hawthorn began in the earliest Miocene as shown
by foraminifera in W-13815 in Nassau County (R. Hoenstine, Fla. Bur.
Geol., personal communication). A core (W-13958) in Indian River
County, Florida, suggests that Hawthorn deposition continued into the
Early(?) Pliocene south of the study area ibidd).
The area extent of the Hawthorn Formation was extended by Cooke
(1945) from Dall and Harris' (1892) descriptions of sections in central
Florida to include strata occurring east of the Apalachicola River, north-
ward to Berkeley County, South Carolina, and southward to cover
almost all of the peninsula of Florida except where it has been com-
pletely eroded. The Hawthorn Formation is present in the subsurface of
the study area except where it is absent due to erosion or possibly
nondeposition near the southeast, south and southwest edges of the
study area.
The authors mentioned in this section were those who defined or
redefined the Hawthorn Formation. Many others have published on the
Hawthorn Formation but have followed the authors mentioned for their
definition of the Hawthorn Formation. They are too numerous to
discuss in this report.

UNDIFFERENTIATED POST-HAWTHORN SEDIMENTS
The undifferentiated post-Hawthorn sediments consist of a variety of
lithololgies. These include fine to coarse quartz sands, occasionally
containing quartz gravel, sandy clay, clay, shell beds, marl and lime-
stone. Formational assignments have been as varied as the lithologies.
Formation names applied, from oldest to youngest, include: Fort
Preston Formation, Jacksonville Limestone, Choctawhatchee Forma-
tion, Duplin Marl, Nashua Marl, Caloosahatchee Marl, unnamed coarse
clastics and terrace deposits.
The Upper Miocene Jacksonville Limestone was named by Dall and
Harris (1892) for a limestone exposed in an excavation near Jackson-






REPORT OF INVESTIGATION NO. 94


ville. It was described as a "...porous, slightly phosphatic, yellow rock
...contains numerous molds of fossil shells belonging to the new
Miocene." Dall and Harris noted occurrences of the Jacksonville
Limestone on Black Creek in Clay County and Preston Sink in Aiachua
County.
Matson and Clapp (1909) called the Jacksonville Limestone the
Jacksonville Formation and described it as a clayey, sandy limestone
with zones of abundant fossils. They differentiated it from the Choc-
tawhatchee Marl in that the Jacksonville Formation contained mica,
more lime and less sand.
Cooke (1945) dropped the name Jacksonville Limestone or Formation
and placed the rocks in the Duplin Marl which he described as a sandy,
shell marl. Cooke differentiated the Duplin from the Choctawhatchee
and restricted the Choctawhatchee to the Florida panhandle.
Bermes, et al. (1963) in their study of Flagler, Putnam and St. Johns
counties simply called these lithologies "Upper Miocene or Pliocene
deposits." Clark, et al., (1964) extended the Choctawhatchee Formation
into northeastern Florida and referred the "late Miocene beds" in
Alachua, Bradford, Clay and Union counties to it.
The Miocene Fort Preston "formation" is an informal name applied
by Puri and Vernon (1964) to the coarse plastic material of peninsular
Florida. Puri and Vernon (1964) described these sediments as "...poorly
sorted quartz grains, ranging in size from fine sand to small pebbles, in a
clay matrix...usually red or orange in color...to white or light yellow
gray." Cooke (1945) had placed these sediments in the Citronelle Forma-
tion. Clark, et al., (1964) stated that their unnamed coarse clastics, which
Puri and Vernon (1964) identified as Fort Preston (Middle Miocene),
overlie the Choctawhatchee Formation which is younger than the Fort
Preston. Due to the nonfossiliferous nature of these clastics, they have
been assigned to several different ages. This has given rise to the confu-
sion which is evident from the variety of names applied to them.
The Nashua Marl was named by Matson and Clapp (1909) for "... Plio-
cene marls extensively developed in the valley of the St. Johns River...."
It was named for the town of Nashua in Putnam County on the St. Johns
River. Matson and Clapp state, "The Nashua Marl bears a strong litho-
logic resemblance to the Caloosahatchee Marl. There is the same alter-
nation of sand beds with shell marl. The matrix of the Nashua Marl,
white, usually calcareous, is always more or less sandy and sometimes
consists of nearly pure sand. The shells are commonly well-preserved
though locally a marl consisting of broken and eroded fragments of
shells is not uncommon." Mansfield (1918) studied the mollusks of the
Nashua and decided they were very similar to the Caloosahatchee Marl.
Cooke and Mossom (1929) equated the Nashua with the Caloosahat-
chee and discarded the term Nashua.
Dall and Harris (1892) described a unit of predominantly sand and
shells in south Florida, giving it the name "Caloosahatchee beds." Mat-
son and Clapp (1909) used the term marl rather than beds. Cooke and
Mossom (1929) brought the term Caloosahatchee Marl into the present
study area when they discarded the Nashua as discussed above.
The unnamed coarse clastics of Clark, et al., (1964) are described as a
"...nonfossiliferous, deltaic deposit that is composed mostly of





BUREAU OF GEOLOGY


varicolored sand and clayey sand that contains quartz gravel locally."
They placed it in the Pleistocene Epoch. These are the same sediments
that Cooke (1945) called Citronelle (Pliocene) and Purl and Vernon (1964)
called Fort Preston (Miocene). This unit is mapped by Purl and Vernon
(1964) as Fort Preston (Miocene). Purl and Vernon mapped the Fort
Preston as occurring in the higher ridges of the study area.
The terrace deposits are often considered to be Pleistocene in age
and are related to the fluctuations of sea level. These deposits include a
wide variety of lithologies occurring at many different elevations. Clark,
et al. (1964) included sands, clayey sands, clays, marls, and shell in this
unit. Clark, et al. (1964), and Bermes, et al. (1963), believed that this unit
blanketed the greater part of the present study area.
Pirkle (1956), in discussing the post-Hawthorn sediments, placed the
units above the Choctawhatchee shell marl in an undifferentiated cate-
gory. Pirkle believed these materials to be Pliocene or Pleistocene. He
states, "...a Pleistocene age is considered far more likely."
In this report the term undifferentiated is used for the sediments
overlying the Hawthorn in the study area due to the evident stratigraphic
confusion that exists. These will be referred to as Undifferentiated Post-
Hawthorn Sediments.

LITHOLOGIC CHARACTERISTICS OF THE HAWTHORN FORMATION
The Hawthorn Formation in the southeast is probably one of the most
misunderstood units in the stratigraphic section. Such glorified terms
as "a garbage can" and "F.U.B.A.R." (Fouled Up Beyond All Recognition)
have been applied to it. The confusion as to what actually constitutes
the Hawthorn Formation is readily understood since the variability of
the sediments is the rule rather than the exception.
The sediments of the Hawthorn Formation consist of widely varying
mixtures of clay, quartz sand, carbonate and phosphate. Beds of end-
member composition (i.e., pure clay) are not common but do occur. The
most common lithologies encountered in the Hawthorn are dolomitic,
clayey sands and clayey andlor sandy dolomites.
Phosphate is virtually ubiquitous throughout the Hawthorn sedi-
ments. The occurrence of phosphate is the most important lithologic
factor in the identification of the sediments grouped in the Hawthorn. It
is, however, not the only factor involved since phosphatic material is
commonly reworked into the overlying, post-Hawthorn units.
The phosphates occur primarily as allochemical grains. These can be
divided into pelletal form and intraclasts. The pelletal grains are the
dominant phosphate form in the Hawthorn of the study area. They are
sand-sized and generally well-rounded with a smooth to polished sur-
face. These grains contain varying amounts of microscopic inclusions
disseminated throughout (Riggs, 1979a). The inclusions are dolomite
rhombs, microfossil debris and terrigenous plastic material. Riggs
(1979a) suggests that the pelletal phosphate was formed by benthic
organisms ingesting the phosphate mud along with the included con-
taminants and excreting these as fecal pellets. Miller (1982) feels that
gentle bottom currents were strong enough to cause the pelletal phos-
phate to form from a phosphatic gel or mud. The pelletal phosphates are
generally black to dark gray but range to tan and white in more weath-






REPORT OF INVESTIGATION NO. 94


ered or reworked sections. The lighter colors are generally found higher
in the section near the upper Hawthorn boundary.
Phosphatized skeletal debris and oolitic or pseudo-oolitic grains are
also found in the Hawthorn Formation. Miller (USGS, 1981, personal
communication) reports oolitic phosphate grains in the Hawthorn in the
Osceola National Forest in the northwestern section of the study area.
Phosphatic intraclasts occur scattered throughout the section but
are most common in the dolomites in the lower Hawthorn. Two types of
intraclasts are recognized in the study cores. First are the phosohate
intraclasts which Riggs (1979a) describes as fragments of penecontem-
poraneous phosphate sediments that have been torn up and rede-
posited. The intraclasts are abraded, rounded and somewhat irregular.
In some of the intraclasts, remnants of original bedding may be seen.
Smaller intraclastic grains may be difficult to separate from the pelletal
forms.
The second type of intraclasts are phosphatized dolomite intraclasts.
These intraclasts show a zoned replacement of dolomite by phosphate.
The zonation trends from unreplaced dolomite in the interior to replace-
ment phosphate at the outer edges. They are irregular and abraded with
somewhat rounded to very rounded edges. This type of intraclast is
most common In the lower Hawthorn dolomites.
Many "rubble" zones occur scattered through the Hawthorn Forma-
tion. These zones consist of phosphate and dolomitic intraclasts incor-
porated in a soft matrix of sand, clay, and dolomite. They appear to repre-
sent periods when the phosphate and carbonate muds were able to
accumulate, become somewhat lithified to well lithified, then were
ripped up and redeposited. The clasts commonly are bored by pele-
cypods and show varying degrees of abrasion.
Phosphate concentrations in the Hawthorn range from zero to greater
than 40 percent. The higher concentrations are uncommon. Average
phosphate concentrations in the Hawthorn range from 5 to 10 percent
based on visual estimates. Reworked Hawthorn sediments form beds
that often contain phosphate in concentrations of 30 to 40 percent
(W-14255, Mizelle #1, Bradford County, for example). Units of this grade
may one day be economically attractive.
The carbonate component of the Hawthorn Formation is composed
predominantly of dolomite. However, limestone and micrite occur
sporadically, both vertically and laterally throughout the area. In general,
limestones account for less than 5 percent of the total Hawthorn car-
bonates. A notable exception to this occurs in the study area well
W-14255, Mizelle #1. The carbonate sediments in the Hawthorn from
Mizelle #1 core are predominantly calcareous with only a minor dolo-
mite component.
Dolomite is common throughout the Hawthorn Formation. It occurs
not only as a dolomite primary lithology but also as a matrix material in
other lithologies. As a result, dolomite is found in virtually the entire
Hawthorn section. Lithologies lacking dolomite are not common but do
occur, particularly as clays.
Dolomitic sediments in the Hawthorn range from poorly consoli-
dated to well-indurated and contain widely variable amounts of quartz
sand, silt, clay and phosphate. They can be subdivided into two basic





BUREAU OF GEOLOGY


categories, doloslits and dolomites. Although they are both composed
of the mineral dolomite and are gradational with one another, they form
two identifiable lithologles and will be discussed separately.
Dolosilts are composed of silt-sized dolomite rhombs with varying
percentages of accessory minerals. Induration is generally poor to
moderate. The accessory minerals are quartz sand, silt, clay and phos-
phate. The phosphate occurrence is related to the occurrence of sand. If
no sand is present, phosphate is generally not encountered. This is
apparently due to the plastic nature of the phosphate grains. The phos-
phate is transported with the sand from areas of primary accumulation
to the areas of dolosilt formation or accumulation.
Dolosllts are often confused with clays by geologists and others
unfamiliar with the peculiarities of the Hawthorn Formation. Admit-
tedly, the dolosilts bear a resemblance to clays, particularly when first
recovered, and they often contain clay in abundance. However, the silty
texture and reaction to dilute HCI Indicate that clay is not the primary
constituent. Examination under a binocular microscope and X-ray
analysis confirm the identity of the dolosilts.
Dolosilts occur throughout the Hawthorn section. However, they
commonly occur higher in the section. Color ranges from yellowish gray
(5Y7/2 or 5Y8/1, GSA Rock Color Chart) to olive gray (5Y3/2 or 5Y4/1).
Dolomites in the Hawthorn Formation are composed of anhedral to
subhedral, crystalline dolomites with varying percentages of accessory
minerals. The dominant accessory minerals are the same as those in the
dolosilts; sand, silt, clays and phosphate. The proportions of these
minerals are highly variable. The dolomites generally range from moder-
ately to well-indurated. Color ranges from light gray (N7) to light olive
gray (5Y5/2 or 5Y6/1). Dolomites often occur interbedded with dolosilts.
The two lithologies also appear to grade into each other. The gradational
nature and the more coarse, intergrown crystalline nature of the dolo-
mites suggest that some of these dolomites are the result of aggrading
neomorphism of the dolosllts.
Dolomites resulting from the replacement of limestone are common
in the Hawthorn, particularly in the lower portion. These dolomites con-
tain fossil molds and fossil "ghosts" that are Indicative of an original
limestone lithology.
The origin of the dolosilts is somewhat of an enigma. As previously
mentioned, they are composed of a poorly consolidated dolomite in the
form of discrete rhombs. They are often intimately mixed with varying
amounts of clay, quartz, silt and sand. Riggs (1979a) suggests that the
dolosilts are detrital, having been transported from source areas south
and east of the present landmass. However, no definitive work has been
done concerning the origin of this sediment type.
,Figures 2, 3 and 4 show the relative percentages of dolomite, sand
and clay units within the Hawthorn. These maps are constructed from
core data only. Percentages of each rock type were determined by add-
ing the thickness of each unit of a specific rock type and dividing by the
total thickness of the Hawthorn Formation in the core. Additional infor-
mation from well cuttings does not provide an accurate indication of the
lithologles due to the loss of softer and finer grained materials during
drilling, sample collection and sample preparation.





REPORT OF INVESTIGATION NO. 94


r- *--^.,2^


1. .. .... A 0 1M n
f 'A)f -LN. CDo fng. gI VO. *
;1 W
*

f .. ..- -



a. -


40

ITIN

t --" ??








junvrrt \ i 'x *'



_ovtc_ _Wj jilt_ 22
j. . -, ..
i-i






Figure 2. Percentage of Dolomite units in the Hawthorn Formation


The total dolomite component of the Hawthorn sediments shows a
trend of Increasing abundance toward the south-central part of the
study area (figure 2). The greatest amount of dolomite in the Hawthorn is
in the southern Clay County-northern and western Putnam County area.
Here cores contain from 50 to more than 70 percent dolomite. The
lowest percentage of dolomite is found in westernmost Bradford
County where less than 10 percent of the Hawthorn Formation is
dolomite. In the study area, the percentage of dolomite Is in the less




BUREAU OF GEOLOGY


than 10 to 70 percent range. Riggs (1979a) places the present study area
in a section of the state In which the Hawthorn Is dominantly terrig-
enous sediments with subordinate carbonates. This suggests that the
abundance of dolomite In the Clay-Putnam county area is somewhat
anomalous and represents a possible carbonate bank. Carbonate sedi-
ments increase In abundance south of the study area becoming the
dominant sediment type In central and southern Florida.
Sand, both as a rock type and as an accessory mineral, is a major con-
stituent of the Hawthorn Formation. It is the most abundant rock type
encountered in the Hawthorn In the study area. Quartz sand also is the
most common accessory mineral in the Hawthorn. Accessory minerals
in the sand-size range include minor amounts of feldspar, heavy
minerals and variable concentrations of phosphate. Pirkle, et al. (1965)
studied the Hawthorn sediments from the Devil's MIlhopper(northwest
of Gainesville, Alachua County) and Brooks Sink (Bradford County).
They analyzed the insoluble residues for percent quartz sand, clay, PaOs,
type and abundance of heavy minerals and size distribution of the
sands. In general, they showed the Hawthorn sands to be In the medium
to fine size classification with the greatest amount of sand retained on
the 60 mesh (20) and 120 mesh (3)) sieves. The heavy minerals found to
be most common were Ilmenite, leucoxene, kyanite, sllimanite, stauro-
lite, epidote and garnet.
Figure 3 is a percent sand (rock type) map. The greatest sand concen-
trations occur in north and northwestern portions of the study area sug-
gesting a source to the north and northwest. Sand content generally
decreases to the south and southeast. A general decrease in average
sand grain size followed the same trend as abundance. The map shows
a northwest-to-southeast trend of a decreasing percentage of sand
units within the Hawthorn in the central portion of the study area.
Clays are present throughout much of the Hawthorn Formation. Most
often the clays are accessory mineral In another dominant lithology,
i.e., clayey, dolomitic sand or clayey, sandy dolomite. However, clay
beds are not uncommon. Figure 4 shows the real distribution of clays
as a percentage of the total Hawthorn section. The maximum percent-
age of clay beds present Is greater than 70 percent In W-14354 In east-
central Putnam County. Clay percentages of 30 to 40 percent are found
along the eastern and southeastern edge of the map. Lower percent-
ages are dominant over most of the remaining map area. (Note the
increase in clay content In Alachua County.)
The clay minerals present In the Hawthorn are palygoreklte, mont-
morillonite, seplollte, Illte, kaollnlte and chlorite (Relk, 1982). Paly-
gorskite and montmorlllonlte are the dominant clays In the Hawthorn of
the study area. Seplolite, Illlte and chlorite are uncommon. Kaollnite is
found only in the more weathered or leached sections of the Hawthorn.

STRATIGRAPHY
The Hawthorn Formation within northeastern Florida unconformably
overlies the Eocene limestones of the Ocala Group. The unconformity
cuts increasingly older rocks toward the southeast. Throughout most of
the study area the first Eocene limestone encountered Is the Crystal





REPORT OF INVESTIGATION NO. 94


Ut "' ",^ f''O, 'V / / tXPLAWAtl&M
1I0- t6,40r 010115 Oo tW
I I'I 'S'I I ; '
S14 .ii k^-

1 0bI C w
-- --- _B^.t_ J.Iil S ^ '' ,J J
r-'-] u.^-- \ \ I ^ ^ ,J \ 6 -- -


1a

1-

t.


Figure 3. Percentage of Sand units in the Hawthorn Formation



River Formation, the youngest unit of the Ocala Group. In eastern and
southeastern Putnam County and into Flagler County, the Williston For-
mation underlies the unconformity in the southeastern most corner of
the study area (Bermes, et al., 1963; Relk, 1980; Leroy, 1981). The entire
Ocala Group Is missing In central Volusia County, southeast of the
study area (Wyrick, 1960). The first Eocene carbonate encountered in
central Volusia County Is the Avon Park Limestone.




16 BUREAU OF GEOLOGY


Figure 4. Percentage of Clay units n the Hawthorn Formation--










Recent Deposits (Bermes, e t a., 1963). Clark, et al., (1964) referred to the
I i '. i


II W"









FigostHawthure 4. Percentage of Clay units n the Hawthorn Formation

The Hawthorn Formation is unconformably overlain by several differ.
ent units. The location within the study area dictates which of the units
lies on the Hawthorn. These units are often lumped Into one of two cate-
gories: (1) Upper Miocene to PlIocene Deposits; (2) Post-Hawthorn to
Recent Deposits (Bermes, et al., 1963). Clark, et al., (1964) referred to the
Post.Hawthorn units as (1)Choctawhatchee Formation, (2)Older Plelsto.
scene Terrace Deposits, (3) unnamed Coarse Clastics. Forthe purposes
of this study formational names were not applied to these units. They
are shown on the cross sections as specific lthologles (figures 5-9).d -






REPORT OF INVESTIGATION NO. 94


0 0R 0 A


UEPLANATIO
-25- COMOUgr flimal 25 NOE
U"r ~ of Hahorn Fm,
- bll (dosNd Wwo nforrod)
Wells
OD :,eas


of---L--i-
ID-



-.4
0
r-

*Z

-\


Figure 5. Location of Cross-Sections


Sandy, often clayey, shell beds overlie the Hawthorn east of central
Clay and Putnam counties (figure 9, DD'). Cross sections AA' and BB'
(figures 6 and 7) clearly show how the shell unit onlaps the Hawthorn.
Also, the clayey sand overlying the shell bed shows a similar relation-
ship. Further west (Inland), the sediments overlying the Hawthorn are
predominantly sands, clays and clayey sands (figures 6 and 7). Scat-
tered lenses or erosional remnants of shell beds and limestone occur
on top of the Hawthorn (W-8400 BB'; W-14283 AA', CC'). The limestone
cropping out in Brooks Sink (Bradford County, T7S, R20E, S12, SW/4, of





BUREAU OF GEOLOGY


SW/4) is an example of the scattered remnants or lenses of carbonate.
The limestone is absent from the cores east and west of the sink
(W-14255 and W-14280). Pirkle (1956) referred to this limestone as lower
Choctawhatchee (Upper Miocene) In age based on ostracods identified
by H. S. Purl of the Florida Bureau of Geology.
The stratigraphy of the Hawthorn Formation is complex and variable.
However, lithologic patterns can be seen when lithologies are grouped
into four categories. These categories, based on the dominant compo-
nent, are dolomite, limestone, sand and clay. As previously stated, the
occurrence of end-member lithologies (i.e., pure sand, etc.) is uncom-
mon. However, they do occur, most often as clays and dolomites.
A generalized, three-part subdivision of the Hawthorn Formation is
obvious from the cross sections (figures 6-9). The cross sections show
an upperdolomite unit overlying a sand and clay member which overlies
a basal dolomite unit. These units are gradational with each other. Each
unit also contains thin beds lithologically similar to the other units. A


Figure 6. Cross-Section A-A'





REPORT OF INVESTIGATION NO. 94


Figure 7. Cross-Section B-B'


fourth unit is recognized in wells in the western portion of the study area
(figure 6, AA', W-14255, W-14280). It occurs at the top of the Hawthorn
and is a unit of reworked clayey, sandy, phosphatic material. Scott (1982)
discussed this briefly.
The upper dolomitic unit consists of sandy to very sandy, sometimes
clayey, phosphatic dolomites. Induration is generally poor to moderate,
however, well-Indurated units do occur. Thin sand beds are common
and thicker sand units occur sporadically. Clay layers also occur in this
member. The upper dolomitic unit is absent in the southeastern corner
of the study area presumably due to erosion (figure 9, DD'). It is also
absent over at least part of the St. Johns Platform (see structure section
and figure 12) again presumably due to post-Hawthorn erosion. West-
ward across the study area, this unit appears to interfinger with and
grade into a more plastic unit similar to the middle member of this study
(figures 6 and 7, AA' and BB').
The middle plastic unit of the Hawthorn Formation in northeast
Florida consists of clayey, dolomitic, phosphatic sands. These are gen-
erally poorly to moderately Indurated. Clays containing widely varying
amounts of sand, dolomite, and phosphate are common, occasionally




BUREAU OF GEOLOGY


comprising the bulk of this member. Thin dolomite beds are also often
present. This unit is present throughout the study area but appears to
become less distinct, merging with the upper and lower members,
toward the north (figure 9, DD').
The basal dolomitic member Is present throughout northeast Florida.
It consists of sandy, sometimes clayey, phosphatic dolomites that are
poorly to well-Indurated. Sand and clay beds also occur In this unit. This
unit thins to the west In the study area and thickens toward the Jackson-
ville Basin (figures 6-9).
Miller (1978) investigated the Hawthorn In the Osceola National
Forest In Baker and Columbia counties. He identified five lithologic
units within the Hawthorn. The units, designated A through E, compare
well with the three units Identified in this report. Miller's basal member,
E, is a carbonate unit comparable to the lower dolomitic unit of this
report. Unit D is a complexly interbedded carbonate-clastic member
representing a transitional sequence between units E and C. Unit C is a
plastic unit comparable to the middle plastic unit of the present study.


Figure 8. Cross-Section C-C'





REPORT OF INVESTIGATION NO. 94


Figure 9. Cross-Section D-D'


Unit B is a plastic (clay) to carbonate member which appears to correlate
with part of the middle plastic unit. Unit A is a carbonate member and
correlates to the upper carbonate-rich unit of this study.
The upper dolomite unit seen on the cross sections crops out in
Brooks Sink, Bradford County. This outcrop reveals the thin bedded
and lithologically variable nature of the upper Hawthorn dolomites
(Scott, 1982).
The lower boundary of the Hawthorn Formation is easily picked
based on a drastic lithologic change. The basal Hawthorn is generally a
brownish to greenish, sandy, phosphatic dolomite and lies directly on a
gray-to-white, often recrystalized limestone.





BUREAU.OF GEOLOGY


As stated previously, the upper surface of the Hawthorn Formation is
an unconformity. Large deposits of dolomitic and phosphatic rubble
often occur here. Variable amounts of phosphate gravel and sand are
often found in the sediments immediately overlying the Hawthorn con-
tact. These rapidly decrease in abundance upward away from the con-
tact until the post-Hawthorn sediments contain only trace amounts of
reworked phosphate.
The upper boundary of the Hawthorn, however, has long been a
source of controversy and misunderstanding. The top of the unit cannot
be picked strictly on the occurrence of phosphate. As previously men-
tioned, phosphate is commonly reworked into the younger sediments.
In northeastern Florida, the most consistent method of recognizing the
top of the Hawthorn is based on the occurrence of a mixture of sand,
clay, phosphate and dolomite (or locally limestone). The sediment is
most commonly a clayey, sandy, phosphatic dolomite or a clayey, dolo-
mitic, phosphatic sand. It lacks shell material and is normally an olive
green to gray-green color.


GEOPHYSICAL INTERPRETATION
Gamma-ray logs are quite helpful in recognizing the approximate
boundaries of the Hawthorn Formation. The Hawthorn, in general, is
marked by gamma-ray activities that are significantly higher than the
overlying and underlying sediments (figure 10). The Hawthorn-Ocala
contact is always marked by a large decrease in activity in the Ocala.
The basal Hawthorn often has strong gamma-ray peaks (greater than
200 counts per second (cps) while the underlying limestones have very
low activities (less than 20 cps). Cavities in the limestones just below
the Hawthorn-Ocala boundary are occasionally filled with Hawthorn
sediments. This produces a gamma-ray peak which occurs below the
contact and may cause a misinterpretation of the boundary. However,
when this occurs the resulting peak is usually more subdued than the
basal Hawthorn peaks.
The gamma-ray signature of the top of the Hawthorn Formation
shows strong peaks (often greater than 150 cps). The overlying sedi-
ments produce gamma-ray peaks that are much less intense than those
of the Hawthorn but greater than the Ocala Group limestones. Immedi-
ately above the uppermost Hawthorn, the gamma-ray peaks may be
quite variable due to the reworking of Hawthorn sediments as pre-
viously mentioned and the occurrence of clays. This can create confu-
sion. However, these peaks are generally less intense than the typical
uppermost Hawthom peaks.
While the upper and lower Hawthorn sediments tend to exhibit
strong gamma-ray peaks, the sediments in between produce much less
intense peaks. Although peaks in these sediments may reach 200 cps
they average much less (around 40 to 50 cps). This contrast produces a
general three part breakdown of the Hawthorn based on gamma-ray
logs (figure 10) which can be traced throughout much of the study area.
However, this division based on gamma-ray activity does not always
correlate closely with the lithologic breakdown described earlier.






REPORT OF INVESTIGATION NO. 94 23


I OCALA
INCREASING ACTIVITY

Figure 10. Typical Geophysical log






BUREAU OF GEOLOGY


STRUCTURE
The Hawthorn Formation unconformably overlies the Ocala Group
limestones and is in turn overlain unconformably by sediments ranging
from Upper Miocene to Recent. The unconformity on top of the Ocala
Group represents an Interval of erosion or nondeposition that Includes
the uppermost Eocene, the entire Oligocene and, in some areas, the
basal Miocene. Figure 11 shows this unconformity and Its relation to the
structural features of the study area. The unconformity encounters


FL~LIANPfBu


w w~


Figure 11. Structure Map of Ocala Group


lk*


~'t m ~






REPORT OF INVESTIGATION NO. 94


Figure 12. Features Expressed on Ocala Group Surface

older rocks towards the southeast. In the southeastern corner of the
map area, the Crystal River Formation (youngest formation of the Ocala
Group) is absent and the underlying Williston-lnglis Formation is
thinned (Leroy, 1981; Leroy and Scott, 1981). In general, the top of the
Ocala Group dips to the northeast toward the Jacksonville Basin
(figures 11 and 12). The direction of dip becomes more northerly along
the eastern edge of the map.
Structural features identified on the Ocala surface are indicated on
figure 12. These are the Nassau Nose, Jacksonville Basin, St. Johns


__





BUREAU OF GEOLOGY


Platform, Baker-Bradford Slope, Marion Plain and the Ocala High. The
dominant structural elements are the Ocala High, the St. Johns Plat-
form and the Jacksonville Basin. The remaining features represent tran-
sitional areas between these major elements.
The Ocala High, often termed the Ocala Uplift (Vernon 1951), is the
dominant feature of west-central and northwestern peninsular Florida
and is an area where the Ocala Group limestones are well above sea
level. The "crest" of the high is located southwest of the study area
where it is breached by erosion exposing the Middle Eocene Avon Park
Limestone. It trends northwest-southeast, plunging gently in both
directions. The eastern flank of the Ocala High can be seen on the west
side of figures 11 and 12.
The St. Johns Platform, named by Riggs (1979a), is a northward dip-
ping extension of the Sanford High. The Sanford High is located south
of the study area in Volusia and Seminole counties. In a regional sense,
the St. Johns Platform parallels the Ocala High (figure 12).
The Jacksonville Basin (Riggs, 1979a) Is the subsurface extension of
the Southeast Georgia Embayment in northeastern Florida. It is sep-
arated from the onshore portion of the Southeast Georgia Embayment
in Georgia by the Nassau Nose. The Nassau Nose is an eastward plung-
ing, apparently anticlinal feature. The Southeast Georgia Embayment
was named by Toulmin (1955). Herrick and Vorhls (1963) state "...the
embayment appears to have originated in Middle Eocene time and con-
tinued as a depositional basin intermittently through Miocene time."
The Jacksonville Basin contains the thickest sequence of Miocene
sediments found in the northern two-thirds of the peninsula. Maximum
Hawthorn thickness is close to 500 feet (150 meters) In the center of
the basin.
The Baker-Bradford Slope lies west of the Jacksonville Basin and the
St. Johns Platform. It trends northwest-southeast, terminating against
the St. Johns Platform (figure 12). Miller (1982), In discussing the phos-
phate in the Hawthorn under the Osceola National Forest (Baker and
Columbia counties), refers to a "hinge line" which strongly affected the
deposition of the phosphorites. This "hinge line" coincides with a por-
tion of the Baker-Bradford Slope. The Baker-Bradford Slope extends
from the Florida-Georgia border southeastward to northeastern Putnam
County. The extent of the slope in Georgia was not investigated in
this study.
South and west of the Baker-Bradford Slope and between the Ocala
High and the St. Johns Platform is the Marion Plain, named by Riggs
(1979a). The Marion Plain is a fairly broad, relatively flat area underlying
eastern Marion County extending northward into Union County. The ero-
sional surface of the Ocala Group dips very gently towards the north-
east where it terminates against the St. Johns Platform to the south and
merges with the Baker-Bradford Slope to the north (figures 11 and 12).
The structure map of the Hawthorn Formation (figure 13) Indicates
that by the end of Hawthorn deposition many of the features noted on
the Ocala Group structure map (figures 11 and 12) are no longer as pro-
nounced. As is the case with the Ocala Group, the top of the Hawthorn
Formation is an unconformity. This, in turn, has modified the existing
structures. The Hawthorn dips gently to the east and northeast.






REPORT OF INVESTIGATION NO. 94 27


One notable structure shown on the Hawthorn structure map is the
low area over the Jacksonville Basin. This lies slightly south of the
thickest accumulations of Hawthorn sediments and may represent a
paleo-dralnage pattern into the embayment. If this feature is an ancient
drainage system, It is Interesting to note that it nearly coincides with the
present course of the St. Johns River.
The isopach map of the Hawthorn Formation (figure 14) shows the
thickest accumulations to be in the northeast, coinciding with the






j /' .
t tt ffiam % 0t ...Hth.n rn

S0.A -







4-f~








I
.. I f- i -, S
















igt






Figure 13. Structure Map of Hawthorn Formation






BUREAU OF GEOLOGY


F 04 1 .
I t4 -n~":7'..ts- '
\fA


--tS- Catonil Inlsevl 2 tet
Ijt1fT IIml 't of ,itwIhoetft tm
S- fo-tll (drathd ho 'lete.ld)
ul co, ____


Figure 14. Isopach Map of Hawthorn Formation



deepest portion of the Jacksonville Basin. The Hawthorn ranges in
thickness from zero in the southwest, west and southeast parts of the
study area to greater than 500 feet in the northeast. The Hawthorn
thickens in a general manner from the southwest to northeast through-
out the study area.
The paleoextent of the Hawthorn Formation beyond its present ero-
sional limits has been postulated by Leroy (1981). Based on the assump-
tion that much of the chert found In the limestones at or nearthe surface





REPORT OF INVESTIGATION NO. 94


of the Ocala High is the result of silica released from the Hawthorn clays
during weathering and erosion of the sediments, the approximate
extent of the Hawthorn can be postulated. This line of investigation sug-
gests that the Hawthorn Formation was probably deposited over almost
all of the Florida peninsula. This approach appears to work well for the
areas west and southwest of the study area. However, it does not appear
to work well for the southeastern portion of the area due to the apparent
lack of chert in the subsurface. The author believes that the paucity of
chert in this area is directly related to the fades present in the
Hawthorn. Figures 2 and 4 show relative dolomite and clay contents of
these sediments. These figures suggest an increased dolomite content
and decreased clay component when comparing southwest and west
with the southeast. With less clay present to be weathered, less chert
(or none) resulted on the Sanford High.

GEOLOGIC HISTORY
The study area has been affected by episodes of erosion, nondeposi-
tion, faulting and warping. The result is an interesting geologic history.
Determination of the geologic history is based almost entirely on sub-
surface data since there are few outcrops within this area.
Although this study did not investigate the deeper subsurface units
(Lake City Limestone, Avon Park Limestone, etc.), other authors have
done so. These include: Bermes, et al. (1963); Clark, et al. (1964); Leve
(1966); Fairchild (1977); Reik (1980); Leroy (1981). The reader should con-
sult these studies for information on the deeper units.
The carbonates of the Upper Eocene Ocala Group were deposited
unconformably on the Avon Park Limestone. The Ocala Group attains a
thickness greater than 300 feet (90 meters) under Duval County in the
Jacksonville Basin. It is probable that the Jacksonville Basin existed at
this time as a shallow basin. This is indicated by a slight thickening of
the Ocala in the basin (Leve, 1966). However, the preservation of this
thickness of Ocala Group limestones was due less to the existence of
the basin at the time of deposition than it was to the subsequent down-
warping of the basin in late Ocala and post-Ocala time, as indicated by
the depth to the Ocala top and the increased thickness of the entire
group in the basin.
The Oligocene Suwannee Limestone was not deposited within tho
study area. It was, however, deposited east of the present shoreline and
is found in the JOIDES 1 drill hole approximately 25 miles (40 km) east of
Fernandina Beach, Nassau County. The nondeposition of the Suwan-
nee or equivalent units within the study area is evident from the lack of
erosional remnants in even the deepest parts of the Jacksonville Basin
while a quite thick section of Ocala Group is present.
The surface of the Ocala Group was exposed to erosion and dissolu-
tion prior to the deposition of the Hawthorn Formation. In the Miocene,
the Hawthorn seas began to encroach on the exposed Florida Platform,
transgressing across it. Accompanying the transgression was an influx
of clastics from the north which filled the Suwannee Straits and began
to enter the carbonate environments of the platform. Within the study
area, the flood of clastics decreased from this time and carbonate-rich





BUREAU OF GEOLOGY


sediments became more important. This is shown by the general three-
part breakdown of the Hawthorn that was discussed earlier in this report
and is seen in the cross sections (figures 6-9).
The Hawthorn Formation was deposited over most of the Florida Plat-
form as is indicated by erosional remnants isolated from the main out-
crop area and from subsurface data. Also, as previously discussed, the
occurrence of chert in the Eocene and Oligocene limestones suggests
that the Hawthorn covered a much larger area in the past (Scott, 1981).
Post-Hawthorn erosion removed the Hawthorn from the Sanford High
and the Ocala High and thinned the unit over much of the remaining
area.
Post-Hawthorn shell beds and limestones appear to have been
deposited during two separate depositional episodes. The limestones
and shell referred to as Choctawhatchee Age (Upper Miocene) by Pirkle
(1956) were possibly deposited prior to the major regression that
occurred in the Late Miocene (Messinian). These were subsequently
highly eroded during the regression leaving only scattered remnants.
These remnants have been discussed by Pirkle (1956), Reik (1980), and
Scott (1982). The second episode of shell bed deposition occurred when
the sea transgressed onto the platform in the Pliocene. The shell units
deposited during this time are found in the eastern half of the study
area.
The post-Hawthorn shell beds and limestones lie on the eroded sur-
face of the Hawthorn. These units contain variable percentages of
reworked Hawthorn sediments. The most easily recognized component
of the reworked sediments is phosphate which is common in the shell
units and is generally most abundant in the shell beds just above the
Hawthorn contact.
In the areas where the shell beds are missing, the sediments
deposited on the Hawthorn are clayey sands and sandy clays. No age
assignment has been possible for the clayey sands and sandy clays.
These in turn are overlain by unconsolidated sands of presumed Pleis-
tocene age. The Pleistocene age for the sands is based on the assump-
tion that the Pleistocene sea levels fluctuated widely and deposited
sands as terrace deposits over the entire state (MacNeil, 1950; Healy,
1975). It is most likely, however, that the higher level terrace sands are
older than Pleistocene.
An episode of structural warping occurred during the period from the
end of the Eocene to the Early Miocene. The Ocala Uplift (Ocala High of
this paper) is postulated to have formed during this event (Vernon, 1951).
The warping that formed the Ocala Uplift also may have formed the San-
ford High, the St. Johns Ridge and associated features. Also, as men-
tioned above, the renewed downwarping of the Jacksonville Basin
occurred during this time. The results of this warping are seen in-the
erosional thinning of the Ocala Group southward from the Jacksonville
Basin onto the Sanford High, south of the study area. The Ocala Group
thins progressively onto the high and is absent over the crest of the
feature. Where the Ocala is absent, the Avon Park Limestone Is the first
carbonate encountered below the undifferentiated sands of Plio-
Pleistocene (?) Age.





REPORT OF INVESTIGATION NO. 94


Many authors believe that faulting occurred during this episode of
deformation. Faults in Duval (Leve, 1966), Clay (Clark, et al., 1964; Fair-
child, 1977; Reik, 1980), and Putnam (Bermes, et al., 1963; Leroy, 1981)
counties have been proposed. These have been postulated in the Ocala
Group, Avon Park Limestone and Lake City Limestone. None of these
faults have previously been identified displacing the Hawthorn Forma-
tion and younger units. This suggests that the deformation ceased prior
to Hawthorn time. The author, however, sees evidence for displacement
of the Hawthorn and younger materials within the study area. This will'
be discussed later. Faults proposed by previous authors and by this
author are shown on figures 6,7,9, 11, and 13. Postulated displacements
of the faults are variable.
Core data from the study area suggest the existence of faults which
occurred during post-Hawthorn time. Figure 9 (cross section DD') indi-
cates where the faults are believed to exist. The faults displace at least
the Ocala group, Hawthorn Formation and the Pliocene shell beds. It is
also possible that the undifferentiated sands overlying the shell beds
were displaced, but there is no evidence at this point to support such a
conclusion. Displacement along these faults reaches a maximum of
approximately 100 feet (30 meters) and decreases northward on the
north-south faults (Leroy, 1981). This can be seen on figure 11. It is inter-
esting to note that the St. Johns River follows this faulted course fairly
well (figure 11). This seems to further substantiate the ideas of Pirkle
(1971) concerning the offset course of the St. Johns River being affected
by faulting.

SUMMARY AND CONCLUSIONS
The Hawthorn Formation in the southeastern United States is prob-
ably one of the most misunderstood units in the stratigraphic section.
The confusion as to what actually constitutes the Hawthorn Formation
is understandable since the variability of the sediments is the rule rather
than the exception.
The sediments of the Hawthorn Formation consist of widely varying
mixtures of clay, quartz sand, carbonate, and phosphate. Beds of a
single sedimentary component (i.e., pure clay) are not common but do
occur. The most common lithologies encountered in the Hawthorn are
dolomitic, clayey sands and clayey and/or sandy dolomites.
Phosphate is virtually ubiquitous throughout the Hawthorn sedi-
ments. The occurrence of the phosphate is the most important litho-
logic factor in the identification of the sediments grouped in the Haw-
thorn. It is, however, not the only factor involved since phosphatic
material is commonly reworked into the overlying post-Hawthorn units.
The phosphates are generally sand-sized grains that are well-rounded
and "polished." They normally contain varying amounts of inclusions
including dolomite rhombs, microfossil debris and plastic grains
(quartz). Phosphate also occurs as intraclasts composed of phosphatic
sediments or phosphatized dolomites. Phosphate concentrations in
the Hawthorn range from zero to greater than 40 percent.
Dolomite is the predominant carbonate present in the Hawthorn For-
mation. It occurs both as a matrix material and as a primary lithology.




BUREAU OF GEOLOGY


The dolomitic sediments range from poorly consolidated to well-Indu-
rated and contain widely varying percentages of quartz sand, silt, clay
and phosphate. Dolosilt, a sediment composed of slit-sized dolomite
rhombs, is a common constituent of the Hawthorn. The dolosilts often
contain variable amounts of clay and are commonly mistaken for clays.
Replacement dolomites are also common. Dolomites and dolosilts
comprise an average of 25 to 40 percent of the Hawthorn within the
study area.
Sand is a major constituent of the Hawthorn Formation. It is the most
abundant lithologic type encountered in the Hawthorn in the study area.
Quartz sand is the most common accessory mineral in the Hawthorn.
Accessory minerals in the sand-size range include minor amounts of
feldspar, heavy minerals and variable concentrations of phosphate.
Clays are present throughout much of the Hawthorn Formation. Most
often the clays are accessory minerals in another dominant lithology,
i.e. clayey, dolomitic sand or clayey, sandy dolomite. However, clay beds
are not uncommon. The clay minerals present in the Hawthorn are paly-
gorskite, montmorillonite, seplolite, illite, kaolinite, and chlorite (Reik,
1982). Palygorskite and montmorillonite are the dominant clays in the
Hawthorn of the study area. Seplolite, illite and chlorite are uncommon.
Kaolinite is found only in the more weathered or leached sections of the
Hawthorn.
Lithologic trends in the Hawthorn show that, within the study area,
dolomite content increases eastward. Sand content is inversely propor-
tional to the dolomite content in that It decreases eastward. Clay con-
tent is greatest in northern St. Johns County near the southern edge of
the Jacksonville Basin. Clay content Is also high in central Aiachua
County.
The complex mixture of clastics and carbonates that comprise the
Hawthorn Formation unconformably overlie the Eocene Ocala Group
limestones. The Hawthorn is in turn unconformably overlain by differing
units depending on the location within the study area. In the eastern half
of the study area, the Hawthorn is overlain by Pliocene shell beds.
Sands and clayey sands overlie the Hawthorn in the western half with
occasional remnants of Upper Miocene limestone and shell units.
The Hawthorn Formation in northeastern Florida can be divided into
three members. In general, the upper unit is predominantly poorly con-
solidated dolomites and dolosllts with varying amounts of sand, silt,
clay and phosphate. The middle member Is largely plastic. It is a poorly
consolidated dolomitic sand with varying percentages of dolomite, clay,
silt and phosphate. The basal member is, once again, predominantly
dolomite. Induration varies from poor to good and percentages of sand,
silt, clay and phosphate vary widely. The three members are gradational
with each other and each member contains beds of lithologies similar
to that found in the other members. Occasionally, a fourth member Is
present at the top. The fourth member consists of reworked Hawthorn
sediments. It is most commonly found in the western half of the study
area.
The dominant structural features affecting the Hawthorn Formation
are the Jacksonville Basin, Ocala High, Sanford High and the St. Johns
Platform. These features are manifested on the Ocala Group and influ-




REPORT OF INVESTIGATION NO. 94 33


enced the deposition of the Hawthorn Formation. These structures are
more subtle on top of the Hawthorn.
The study area has been affected by episodes of warping and fault-
ing. The first episode of warping that is identified occurred during the
period from latest Eocene through Early Miocene. This episode formed
the Ocala High (Uplift), St. Johns Platform, Sanford High and associated
features. The Jacksonville Basin is thought to have existed as a more
shallow basin prior to this time and was deepened considerably during
the period of deformation. Faulting occurred during this period dis-
placing the Ocala Group. An episode of faulting is postulated in eastern
Putnam County which occurred after the deposition of the Pliocene
shell beds. Faulting in the study area has a maximum displacement of at
least 100 feet. It is Interesting to note that the St. Johns River follows
proposed fault zones fairly closely.






34 BUREAU OF GEOLOGY


REFERENCES
Applin, P. L and E. R., Applin, 1944, Regional subsurface stratigraphy and structure of
Florida and South Georgia: Bulletin American Association of Petroleum Geologists,
Vol. 28, No. 12.
Bermes, B. J., G. W. Leve, and G. R. Traver, 1963, Geology andground water resources of
Flagler, Putnam and St, Johns counties, Florida: Florida Geological Survey Report
of Investigation 32.
Brooks, H. K., 1966, Geological history of the Suwannee River: In Miocene-Pliocene
Series of the Georgia Florida Area: Southeastern Geological Society Guidebook 12.
Brooks, H. K., 1967, Miocene-Pliocene problems of peninsular Florida: In Miocene-
Pliocene Problems of Peninsular Florida: Southeastern Geological Society
Guidebook 13.
Clark,W. E, R. H. Musgrove, C. G. Menke, and J. W. Cagle, Jr., 1964, Water resources of
Alachua, Bradford, Clay and Union counties, Florida: Florida Geological Survey
Report of Investigation 35.
Conrad, T. A, 1846, Description of new species of organic remains from the Upper
Eocene limestones of Tampa Bay, Florida: American Journal of Science Series 2.
Cooke, C.W., 1915, The age of the Ocala Limestone: U.S. Geological Survey Professional
Paper 95.
Cooke, C.W. and S. Mossom, 1929, Geology of Florida: Florida Geological Survey Annual
Report 20.
Cooke, C. W., 1945, The Geology of Florida: Florida Geological Survey Bulletin 29.
Dail, W. H. and G. D. Harris, 1892, Correlation paper-Neocene: U.S. Geological Survey
Bulletin 84.
Dall, W. H., 1896, Descriptions of Tertiary fossils from the Antillean region: U.S. National
Museum Proceedings, Vol. XIX, No. 1110.
Dall, W. H., 1903, Contributions to the Tertiary fauna of Florida: Wagner Free Inst. of Scl.
Trans., Vol. 3, Parts 1-6.
Espenshade, G. H. and C. W. Spencer, 1963, Geology of phosphate deposits of northern
peninsular Florida: U.S. Geological Survey Bulletin 1118.
Fairchild, R.W., 1977, Availability of water In the Floridan Aquifer in southern Duval and
northern Clay and St. Johns counties, Florida: U.S. Geological Survey Water
Resources Investigation 76-98.
Healy, H. G., 1975, Terraces and shorelines of Florida: Florida Bureau of Geology Map
Series 71.
Herrick, S. M. and R. C. Vorhis, 1963, Subsurface geology of the Georgia Coastal Plain:
Georgia Department of Mines, Mining and Geology, Information Circular 25.
Johnson, L C, 1888, The structure of Florida; American Journal of Science, 3rd Series,
Vol. 36.
Leroy, R. A., 1981, The Mid-Tertiary to Recent llthostratlgraphy of Putnam County,
Florida: Unpublished M.S. Thesis, Florida State University, Tallahassee.
Leroy, R. A. and Scott, T. M., 1981, The Mid-Tertiary to Recent stratigraphy In Putnam
County, Florida: Abstract, Florida Academy of Sciences Journal, Vol. 44, Supple-
ment 1.
Leve, G. W., 1966, Ground water in Duval and Nassau counties, Florida: -Florida
Geological Survey Report of Investigation 43.
MacNeil, F. S., 1950, Pleistocene shorelines in Florida and Georgia: U.S. Geological
Survey Professional Paper 221-F.
Mansfield, W. C., 1918, Molluscan faunas from the calcareous marls in the vicinity of
Deland, Volusia County, Florida: Florida Geological Survey Annual Report 10-11.
Matson, G. C. and F. G. Clapp, 1909, A preliminary report on the Geology of Florida:
Florida Geological Survey Second Annual Report.






REPORT OF INVESTIGATION NO. 94 35


Miller, J. A., 1978, Geologic and geophysical data from Osceola National Forest, Florida:
U.S. Geological Survey Open File Report 78-799, p. 101.
Miller, J. A., 1982, Structural and sedimentary setting of phosphate deposits in North
Florida and North Carolina: Miocene of the Southeast United States, Proceedings
of the Symposium, T. Scott and S. Upchurch (eds.): Florida Bureau of Geology
Special Publication 25.
Pirkle, E. C., 1956, The Hawthorn and Alachua Formations of Alachua County, Florida:
Florida Academy of Sciences, Vol. 28.
Pirkle, E. C., W. J. Yoho and A. T. Allen, 1965, Hawthorn, Bone Valley and Citronelle
sediments of Florida: Florida Academy of Sciences, Vol. 28.
Pirkle, W. A., 1971, The offset course of the St. Johns River, Florida: Southeastern
Geology, Vol. 13, No. 1.
Purl, H. S., 1957, Stratigraphy and zonation of the Ocala Group: Florida Geological
Survey, Bulletin 38.
Purl, H. S. and R. O. Vernon, 1964, Summary of the geology of Florida and a guidebook to
the classic exposures: Florida Geological Survey Special Publication No. 5
(revised).
Reik, B. A., 1980, The Tertiary stratigraphy of Clay County, Florida with Emphasis on the
Hawthorn Formation: Unpublished M.S. Thesis, Florida State University,
Tallahassee.
1982, Clay mineralogy of the Hawthorn Formation in northern and eastern Florida:
Miocene of the Southeastern United States Proceedings of the Symposium,
T. Scott and S. Upchurch (eds.): Florida Bureau of Geology Special Publication 25.
Reynolds, W. R., 1962, The Lithostratigraphy and Clay Mineralogy of the Tampa-
Hawthorn Sequence of Peninsular Florida: Unpublished M.S. Thesis, Florida State
University, p. 126.
Riggs, S. R., 1979a, Phosphorite sedimentation In Florida-A model phosphogenic
system: Economic Geology, Vol. 74, No. 2.
1979b, Petrology of the Tertiary phosphate system of Florida: Economic Geology,
Vol. 74, No. 2.
Scott, T. M., 1981, The paleoextent of the Miocene Hawthorn Formation in peninsular
Florida: Abstract, Florida Academy of Sciences Journal, Vol. 44, Supplement 1.
- 1982, A comparison of the "cotype" localities and cores of the Miocene Hawthorn
Formation: Miocene of the Southeastern United States Proceedings of the Sympo-
slum, T. Scott and S. Upchurch (eds.): Florida Bureau of Geology Special Publica-
tion 25.
- and P. L. MacGill, 1981, The Hawthorn Formation of Central Florida: Florida
Bureau of Geology Report of Investigation 91.
Sever, C. W., J. B. Cathcart and S. H. Patterson, 1967, Phosphate deposits of south-
central Georgia and north-central peninsular Florida: South Georgia Minerals Pro-
gram, Project Report 7.
Smith, E. A., 1881, On the geology of Florida: American Journal of Science, Series 3,
Vol. 21.
Toulmin, L. D., 1955, Cenozoic geology of southeastern Alabama, Florida and Georgia:
American Association of Petroleum Geologists Bulletin 39, No. 2.
Vaughan, T. W. and C. W. Cooke, 1914, Correlation of the Hawthorn Formation:
Washington Academy of Sciences Journal, Vol. 4, No. 10.
Vernon, R. 0., 1951, Geology of Citrus and Levy counties, Florida: Florida Geological
Survey Bulletin 33.
Williams, G. K., 1971, Geology and geochemistry of the sedimentary phosphate deposits
of northern Peninsular Florida: Unpublished Ph.D. Dissertation, Florida State
University, Tallahassee.
Wyrick, G. G., 1960, The ground water resources of Volusia County, Florida: Florida
Geological Survey Report of Investigation 22.





36 BUREAU OF GEOLOGY





REPORT OF INVESTIGATION NO. 94


APPENDIX


DATA FOR CORES USED IN THIS STUDY





38 BUREAU OF GEOLOGY














CORES USED IN THIS STUDY*
(Sea Level Datum)


ALACHUA COUNTY


NAME
Hawthome i
Devils Millhopper #1


Trail Ridge #3
ONF-6
ONF-7



Ralford 11
Mlzelle #1
Vames #1
Wainwright


LOCATION
10S22E 3SW NE
9S 19E 15 NW 8E



2822E15 SE SE
2S19E 2NWNW
2 19E30NWSW



5S21E26 NE NW
7819E 1 SE NW
7S21E 4SW NE
6S22E 24 SE SW


ELEV


TOP OF
TD HAWTHORN


100 45
178 + 46

BAKER COUNTY
167 -121
132 -162
141 67

BRADFORD COUNTY
128 -144
133 7
140 35
181 -101


- 89
+167.5



- 13
+ 98
+121


+ 88
+115
+113
+ 93


TOP OF
OCALA
- 345
+ 09


GEOPHYSICAL"
LOGS


-140
- 415



-143.5
+ 22
-0-
+ 15


*Data in feet To convert multiply feet x 03048 to get meters.
G 6 = Gamma Ray, C Callper,E = Electric.


WELL
NUMBER


13813
14255
14280
14283













58 23E 31 NE 8E
6826E 7 W 8E
48 23E 16 NW 8E
48 25E 13 NW 8W
48 24E 27 E 8E
7824E20 NE 8W
68 26E 17 NW NE
78 26E 38 SW 8W


10486
13709
14179
14193
14219
14301
14476
14521



14619



13815



8400
14318
14346
14353
14354
14376
14477
14566
14594


3N 24E 32 NW NW



98 2E 18 SW NW
13828E 7 W NW
924E 9 NE NE
11826E278W NE
98 27E 49
10S 27E 41
8 27E 26 8W SW
1024E 3 NE NE
98 23E18 NE NE



8 28E38 NW
5S28E11SW NE
6828E14 NE NW
10S 30E 37
88 28E 20 NE NE


Dupont I1
Harris I1
Long Branch 01
Fox Meadows #1
Jennlngs #1
Valledejul 91
Kuhrt #1
Miss J #1


- 6
-206.5
-206
-275
-340
- 02
-341
-273


1827E42


13744
13751
13786
13844
14413


0
C, E, Q
C, E.
C, E, G
0
a
a


CLAY COUNTY
23 93
97 -222
86 -234
80 -307
80 -402
166 87
62 -383
80 -306

DUVAL COUNTY
12 -488

NASSAU COUNTY

80 -410

PUTNAM COUNTY

210 92
64 -94
90 -92
86 -80
18 -134
14 -238
12 -225
80 -146
166 84

ST. JOHNS COUNTY

28 -224
61. -281
31 -211
10 -168
19 -230


Carter 1



Cassidy #l


Baywood #1
Nichols #1
Moody 91
Merritt 1
East Platka #1
Devils Elbow #1
Bostwick #1
Atchenison #1
Hall-Putnam l1



Scott #1
Scott #2
Scott #3
Zonker #1
Parker Farms #1


- 68



- 52


+36
- 44
+ 20
+ 5
-27
-127
- 94
+ 5
+ 66.5


-402


-87
- 5.5
-77
- 57
- 90.7
-187
-204
-120.5
- 64


-209
-239
-201
-127
-223






REPORT OF INVESTIGATION NO. 94


THE HAWTHORN FORMATION OF NORTHEASTERN FLORIDA




PART II

CHARACTERIZATION AND BENEFICIATION OF THE
NORTHEASTERN FLORIDA PHOSPHATE-BEARING
HAWTHORN FORMATION


By
B. E. Davis, G. V. Sullivan and T. O. Llewellyn
U. S. Bureau of Mines, Tuscaloosa Research Center
Tuscaloosa, Alabama


Research at the Tuscaloosa Reearoh Center ai carried out under a memorandum of agreement between the Bureau of
Mines, U. S. Department of the Interior, and the University of Alabama.





42 BUREAU OF GEOLOGY


TABLE OF CONTENTS

Page
Abstract .............. ...................................... ... 44
Introduction ........................................................... 45
Locationand Description of Cores......................................... 45
Characterization Studies ............................................... 48
PhosphateAnalyses .................................................. 48
SieveAnalyses ................ .................................... 49
PetrographicAnalyses ................................................. 49
Heavy-Liquid Separation ............................................... 50
Flotation Studies .................... .............................. 51
13765 Scott No. 3 ...................................................... 51
13814Raiford .................................................. 53
14179Long Branch .................................................. 53
14219Jennings ....................................... ............... 53
14255Mizelle ......................................................... 53
14280Vames ......................................................... 54
Sedimentation of Slimes ................................................. 54
Conclusions ........................................................... 55
References ......... ................................................... 56
Appendices ............................................................ 57
A. POs analyses of core intervals of the Hawthorn Formation ................. 59
B. Sieve analyses of composite sections of the Formation ................... 67
C. Petrographic analyses of composite sections of the Hawthorn Formation .... 75
D. Heavy-liquid separation analyses of composite sections of the
Hawthorn Formation ................ ...............................83





REPORT OF INVESTIGATION NO.94 43


ILLUSTRATIONS

Figure Page
1 Location of core holes from the Hawthorn Formation ...................... 46
2 Minus 14-plus 20-mesh grains of core No. 14179 of the Hawthorn Formation .... 50
3 Flow chart of general flotation scheme of composite sections of the
Hawthorn Formation ................................................ 52

TABLES

1 Core hole physical data of the Hawthorn Formation drill cores ................ 47
2 P2Os statistical data of drill cores of the Hawthorn Formation ................. 48
3 Chemical analyses, length, and location of composite sections of the
Hawthorn Formation .................. .. .... ........... .... 49
4 Concentrate data of flotation studies of composite sections of the
Hawthorn Formation ...............................................54





BUREAU OF GEOLOGY


CHARACTERIZATION AND BENEFICIATION OF THE NORTHEAST
FLORIDA PHOSPHATE-BEARING HAWTHORN FORMATION

By
B. E. Davis,' G. V. Sullivan,2 and T. O. Llewellyn 3


ABSTRACT
In keeping with its mission of developing technology that could
assist in maintaining adequate supplies of minerals, the Bureau of
Mines conducted characterization and beneficiation studies of drill
cores of the Hawthorn Formation in northeast Florida. The core
samples were obtained by contract with the Florida Bureau of Geology.
Twenty-three cores from Bradford, Clay, Putnam, and St. Johns Coun-
ties were processed. Each 10-foot interval of the cores was analyzed for
P20s content. Adjacent intervals containing more than 5 percent P2Os
were combined for further studies. The composite sections were
characterized by their chemical composition, size, specific gravity, and
mineralogical constituents. These studies showed that (1) the core
samples were composed of phosphate, quartz, carbonate, and clay;
(2) most of the carbonate and clay was very fine grained; and (3) con-
centration of the phosphate by physical means should be possible.
Beneficiation studies indicated that flotation could produce phosphate
concentrates that contained 24.2 to 29.0 percent P20s with attendant
recoveries of 32.1 to 82.3 percent.








' Minerals engineer.
SSupervisory (research) metallurgist.
*Supervisory (group) metallurgist.
All authors are with the US. Department of the Interior, Bureau of Mines, Tuscaloosa Research Center, Tuscaloosa,
Alabama.





REPORT OF INVESTIGATION NO. 94


INTRODUCTION
The importance of fertilizer in the production of food is self-evident.
As population increases, so will the need for food and the demand for
fertilizer. This demand for phosphate rock in the United States is
predicted to increase by 47 percent by the year 2000 (Stowasser, 1979).
Presently, 80 percent of domestic phosphate production is from the
Bone Valley Formation in central Florida. This phosphate is mined by
stripping up to 50 feet of overburden, slurrying the phosphate matrix,
and pumping it via a pipeline to the concentration plant. At the concen-
tration plant a pebble product (plus 14-mesh) is produced by sizing. The
remaining material is deslimed at 150 mesh and a phosphate concen-
trate is produced by flotation. The flotation scheme involves a fatty acid-
fuel oil rougher float of the phosphate, a de-oiling step, and amine flota-
tion of the remaining quartz mineral. Generally, the ore mined is 10 to 15
percent P205 and is upgraded to 29 to 32 percent P20s with 80 percent
recovery of phosphate from the flotation feed (Zellers and Williams,
1978, p. 57).
The Bone Valley deposits are said to contain enough phosphate to
meet demands for the next two decades (U. S. Comptroller General,
1979, p. 1). As this rich deposit is depleted, other sources must be
developed. To enhance its mission of classifying domestic mineral
resources and reserves, the Bureau of Mines entered contract No.
G0166038 with the Florida Bureau of Geology to study one of the pos-
sible future sources, the Hawthorn Formation. This formation may con-
tain scores to hundreds of billions of tons of phosphate (Cathcart and
Gulbrandsen, 1973, p. 521). The Hawthorn Formation underlies a large
region of Florida extending from the Bone Valley to the east coast as far
north as southern Georgia and is a phosphate-bearing dolomitic
limestone formation. The Hawthorn Formation has been described in
numerous publications.
Under the contract, the Florida Bureau of Geology conducted the
drilling operations and sent splits of the cores to the Tuscaloosa
Research Center. The Tuscaloosa Research Center conducted charac-
terization and beneficiation studies of these cores. This report summar-
izes the results of these studies.




LOCATION AND DESCRIPTION OF CORES
The drilling operation was confined to a four-county area with the
exception of one core hole. Drilling procedure consisted of drilling to
the bottom of the Miocene-Hawthorn Formation where it meets the
Eocene-Ocala Group limestones, as visually determined by the core
drillers. Twenty-three holes were drilled by the Florida Bureau of
Geology. Four core holes were located in Bradford County, six in Clay
County, eight in Putnam County, four in St. Johns County, and one in the
Ocala National Forest in Marion County. Table 1 gives the core hole
physical data for the 23 core holes. Figure 1 shows the location of cores
within the counties.





BUREAU OF GEOLOGY


Figure 1. Location of core holes from the Hawthorn Formation


The cores were divided into 10-foot intervals, sealed in polyethylene
bags to retain original bed moisture, and delivered to Tuscaloosa by the
Florida Bureau of Geology. The cores varied in their physical appear-
ance; some of the intervals were almost all very tightly compacted clay.
Other intervals consisted of sand with small nodules of phosphate. Still
others contained clay and dolomitic limestone. Some of the cores con-
tained a mixture of all of the above. A few of the cores contained marine
fossils and shells. In none of the intervals was any pebble size phos-
phate found.













Table 1.-Core hole physical data of the Hawthorn Formation drill cores

Core F____eet
No. Name County Location Total depth Cored -Core length
13744 Scott #1 .............. St. Johns T6S, R28E, 5.38 Irregular NE 184 162 -184 22
13751 Scott #2 ............ St. Johns T5S, R28E, 5.11 SW NE 240 80.5-240 120.5
13765 Scott #3.............. St. Johns T6S, R28E, 5.14 NE NW 216 60 -216 119
13814 Ralford .............. Bradford TSS, R21E, 5.26 NE NW 272 40 -272 224
14179 Long Branch.......... Clay T4S, R23E, 5.16 NW 1/4 SE 114 290 60 -290 230
14193 Fox Meadow .......... Clay T4S, R25E, 5.13 NW 1/4 SW 114 325 73 -325 248
14219 Jennings ............ Clay T4S, R24E, 5.27 SE 1/4 SE 1/4 431 60 -431 351
14255 Mizelle .............. Bradford T7S, R19E, 5.01 SE NW 110 10 -110 100
14280 Varnes............... Bradford T7S, R21E, 5.04 SE NE 167 20 -167 147
14283 Wainwright ........... Bradford T6S, R22E, 5.24 SE SW 270 47.5-270 195
14301 Valledujal ............ Clay T7S, R24E, 5.20 NESW 230 120 -230 110
14315 JuniperSprlngs#1 ..... Marion T15S, R26E, 5.20 NW NE 108 87 -108 21
14318 Nichols ............. Putnam T13S, R28E, 5.07 SWNW 75 11 75 55
14346 Moody#1 ............ Putnam T9S, R24E, 5.09 NW NE NE 190 80 -190 97
14353 Merritt ............... Putnam T11S, R26E, 5.27 SW NE 147 85 -147 62
14354 East Palatka .......... Putnam T9S, R27E, 5.49 Irregular 109 46 -109 63
14376 Devils Elbow.......... Putnam T10S, R27E, 5.41 Irregular 200 92 -200 108
14413 ParkerFarms ......... St. Johns T8S, R28E, 5.20 NE NE 243 72 -243 171.5
14476 Kuhrt ............... Clay T6S, R26E, 5.17 NE NE NW 403 114 -403 282
14477 Bostwick ............ Putnam T7S, R27E, 5.26 SW SW SW 216 91 -216 125
14521 MlssJ ............... Clay T7S, R26E, 5.36 SW 353 140 -353 193
14566 Atchenson ........... Putnam T10S, R24E, 5.03 NE NE 200 78 -200 122
14594 Hall #1 .............. Putnam T9S, R23E, 5.18 NE NE 230 100 -230 129


39 .. .
0



-I





0:
Z:
0
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BUREAU OF GEOLOGY


CHARACTERIZATION STUDIES


PHOSPHATE ANALYSES
Each 10-foot interval of the cores was crushed to pass 3 mesh. The
minus 3-mesh intervals were mixed by cone and quartering and a sam-
pie was taken. The sample was dried in a low-temperature dryer and pre-
pared for chemical analyses. Each 10-foot Interval was analyzed for P2Os
content. The P20 content of the Intervals ranged from 0.1 percent to
19.9 percent. The average P2aO content for the counties was as follows:
Bradford, 3.5 percent; Clay, 2.3 percent; Putnam, 1.7 percent; St. Johns,
2.9 percent. The four-county average was 2.5 percent P2O,. Appendix A
gives the P2Os content of the Intervals for each core hole, and table 2
gives the statistical data for each of the core holes. Table 2 also gives
the number of intervals containing greater than or equal to 5 percent
P20.




Table 2.-P20% statistical data of drill cores of the Hawthorn Formation

Core Percent P.O Intervals
No. Name County Low High Mean > 5 pot PO,
13744 Scott ............ St. Johns 0.7 6.8 4.5 2
13151 Scott 2 ............ St. Johns 0.1 2.0 1.0 0
13785 Scott 3 ............ St. Johns 0.1 19.9 3.9 2
13814 Raitord............. Bradford 0.7 7.2 3.6 3
14179 Long Branch ........ Clay 0,9 10.4 3,0 2
14193 Fox Meadow ........ Clay 0.1 4.8 1.9 0
14219 Jennlngs ........... Clay 0.9 7.8 2.8 5
14255 Mlzelle ............. Bradford 0.7 13,5 4.9 3
14280 Varnes ............. Bradford 1.2 8,8 3.2 1
14283 Wainwright ......... Bradford 0.1 4.8 2,3 0
14301 Valledual .......... Clay 1.1 6.9 2.6 1
t43t5 JuniperSprings t ... Marion 0.1 15.1 7.6 1
14318 Nichols ............ Putnam 0.1 1.2 0.3 0
14346 Moody #1 ........... Putnam 0.1 2.7 1.3 0
14353 Merritt ............ Putnam 0.6 3.3 2.2 0
14354 East Palatka ........ Putnam 1.5 3.7 2.4 0
14376 Devils Elbow ........ Putnam 0.7 3.2 1.9 0
14413 Parker Farms........ St. Johns 0.3 7.7 2.2 2
14476 Kuhrt .............. Clay 0.3 5.0 2.1 0
14477 Bostwick ........... Putnam 0.2 7.8 2.1 1
14521 MissJ ............. Clay 0.1 6,4 1.2 1
14568 Alchenson.......... Putnam 0.1 7.0 1.6 1
14594 Hall #1 ............ Putnam 0.1 8.6 1.6 1


For beneficiation studies, adjacent intervals that contained greater
than or equal to 5 percent P205 were combined. The result was six com-
posited sections for further study. The composite sections were the
182 to 216-foot sections of Scott No. 3; the 40 to 120-foot section of
Raiford; the 70 to 90-foot section of Long Branch; the 80 to 130-foot sec-
tion of Jennings; the 10 to 80-foot section of Mizelle; and the 30 to
60-foot section of Varnes. The chemical analyses, length, and location
of the composite sections are shown In table 3. The remainder of this
report deals with these six composite sections.





REPORT OF INVESTIGATION NO. 94


Table 3.-Chemical analyses, length, and location of
composite sections of the Hawthorn Formation
Core Section of core, feet Analyses, percent
No. Name County Interval location Total PieO CaO MgO CO0 Insol
13765 Scott #3...... St. Johns 182-216 34 16.7 27.7 2,6 0.7 33,6
13814 Ralford ...... Bradford 40-120 80 6.0 28.2 7.8 16.1 45.7
14170 Long Branch.. Clay 70- 90 20 7.0 24.1 6,5 12.6 43.5
14219 Jennings .... Clay 80-130 60 6.3 15.9 3.1 4,5 85.7
14266 Mlelle ....... Bradford 10- 80 70 7.0 14.1 1.8 2.8 66.1
14280 Varne ....... Bradford 30- 60 30 5.5 25.7 7.4 15.0 45,2


SIEVE ANALYSES
Sieve analyses of the six composite sections showed that the dis-
tribution of products relative to size was varied from one core to another.
However, some generalities were evident. A pebble size (plus 14-mesh)
concentrate was not present in the Hawthorn Formation phosphate.
Most of the phosphate was contained in the plus 150-mesh material.
Quartz (insol) was fairly well distributed with a majority appearing in the
minus 28-plus 150-mesh size range. Most of the clay and dolomite
reported to the minus 400-mesh slimes. The weight-percent of material
contained in the minus 400-mesh slimes ranged from 14.8 to 27.5 with an
average of 19.7. The distribution percent of MgO contained in the slimes
ranged from 35.4 to 57.1 with an average of 49.0. The distribution percent
of P2aO contained in the slimes ranged from 1.7 to 28.1 with an average
of 8.9. X-ray diffraction analyses of the slimes identified dolomite as the
major mineral present with minor amounts of apatite, quartz, and atta-
pulgite. Detailed sieve analyses of the six composite sections are
presented in Appendix B.

PETROGRAPHIC ANALYSES
Petrographic studies indicated that the mineral constituents of the
six composite sections were very similar. Therefore, petrographic
description will be generalized for the six sections.
The dominant phosphate mineral in the samples was carbonate-fluor-
apatite. The mineral ranged in color from light tan to black and was
mainly rounded in shape. The larger grains contained some locked fine
quartz sand. Some of the grains contained coatings or films of clay-
dolomite which were easily removed by scrubbing.
Quartz grains in the samples were rounded to subrounded in the
coarse fractions, becoming angular in the finer sizes. The dolomite
ranged in color from white to light gray and consisted of minus
200-mesh aggregates which were fairly well cemented. Clay in the
samples was light colored and mostly finer than 400 mesh. Some clay
was aggregated with the dolomite, and these aggregates appeared in
several size fractions. The clay minerals consisted of montmorillonite,
attapulgite, and some sepiolite. The samples also contained minor
amounts of feldspar, calcite, and heavy minerals. The heavy minerals
present were epidote, sillimanite, garnet, muscovite, and zircon. Figure
2 is an example of grains present in the minus 14-plus 20-mesh frac-
tion of core No. 14179. The black grains are carbonate-fluorapatite, the
white grains are dolomite, and the clear ones are quartz.





BUREAU OF GEOLOGY


Figure 2. Minus


14-plus 20-mesh grains of core No. 14179 of the
Hawthorn Formation. (20 x)


Three of the sections were free of any locking. The others contained
locking in the plus 35-mesh sizes. To assure liberation and facilitate
other studies, the samples were ground to pass 35 mesh. Appendix C
contains the petrographic analyses for the six composite sections.

HEAVY-LIQUID SEPARATION
To determine the results that could be expected in beneficiation,
heavy-liquid separation tests were conducted on samples of the six





REPORT OF INVESTIGATION NO. 94 51


composite sections. The samples were deslimed at 400 mesh and
ground to pass 35 mesh. After grinding, they were deslimed and separ-
ated into minus 35-plus 150-mesh and minus 150-plus 400-mesh frac-
tions. These two size fractions of each sample were separated at the
following specific gravities: 2.68, 2.75, 2.85, and 2.93.
As expected, the quartz (acid insol) reported to the float-2.68 fraction
and the sink-2.68 float-2.75 fraction. Most of the dolomite reported to the
sink-2.75 float-2.85 fraction. The phosphate mineral was contained in
the sink-2.85 float-2.93 and sink-2.93 fractions. The composite P205
content in these fractions ranged from 26.3 percent to 32.0 percent with
an average of 28.0 percent. The accompanying distributions, in percent,
ranged from 64.9 to 86.8 with an average of 73.7. Heavy minerals that
were contained in the sink-2.93 fraction are listed in the petrographic
section of this report. Complete heavy liquid separation data are given
in Appendix D.


FLOTATION STUDIES
Beneficiation studies of the six composite sections consisted of
scrubbing-desliming and flotation to concentrate the phosphate min-
eral. The general scheme, with slight variations, consisted of weighing
out a determined amount of material, slurrying it and desliming it at 400
mesh. This product was considered the primary slimes. The deslimed
pulp was ground to pass 35 mesh in a pebble mill. The minus 35-mesh
pulp was deslimed at 400 mesh to produce the secondary slimes. The
minus 35-plus 400-mesh pulp was scrubbed in an attrition scrubber to
clean phosphate mineral faces of any remaining dolomite and to break
up any remaining dolomite aggregates.
Sodium hydroxide was added to the scrubbing stage as a pH regu-
lator and dispersant. After scrubbing, the material was deslimed at 400
mesh, producing the scrub slices. The deslimed pulp was conditioned
with fatty acid and fuel oil at 60 percent solids in a laboratory flotation
machine, and a rougher phosphate concentrate floated. The rougher
concentrate was cleaned several times in the presence of sodium
silicate to depress the remaining gangue minerals. Figure 3 is a flow
chart of the scheme.



13765-SCOTT #3
A flotation feed from Scott #3 composite sections was prepared as
previously described. A total of 51.9 percent of the MgO was removed in
the three slime products, with a loss of 15.4 percent of the P20s. The
deslimed pulp was conditioned with fatty acid and fuel oil in the
amounts of 0.96 and 1.44 pounds per ton of ore, respectively, and a
rougher phosphate concentrate floated. After cleaning three times in
the presence of sodium silicate, the concentrate contained, in percent,
29.0 P205, 50.1 CaO, 1.0 MgO, 7.9 CO2, and 4.5 acid-insoluble material,
with a 76.9-percent recovery of the P205 in the flotation feed. The total
recovery of the P205 from the core section was 64.9 percent.




52 BUREAU OF GEOLOGY


Composited section



Slurry



Deslime --- Primary slimes


Grind



Deslime --Secondary slimes


Attrition scrub


Deslime --Scrub slimes


Rougher flotation ---Rougher tailings


Cleaner flotation --- Cleaner tailings


Concentrate

Figure 3. Flow chart of general flotation scheme of composite
sections of the Hawthorn Formation





REPORT OF INVESTIGATION NO. 94


13814-RAIFORD
A flotation feed was prepared from Raiford composite sections as
previously described. A total of 83.5 percent of the MgO was removed in
the slimes with a loss of 17.9 percent of the P20. The pulp was condi-
tioned with fatty acid and fuel oil in the amounts of 0.64 and 0.96 pound
per ton of ore, respectively. A rougher concentrate was floated and
cleaned six times in the presence of sodium silicate. The final concen-
trate contained, in percent, 28.0 P20s, 53.6 CaO, 1.3 MgO, 8.0 CO2, and
3.2 acid-insoluble material. The attendant recovery was 54.8 percent of
the P20s in the flotation feed. The total recovery of the P20s was 45.1:per-
cent.


14179-LONG BRANCH
A flotation feed sample was prepared as previously described from
Long Branch composite sections. A total of 75.2 percent of the MgO
was removed in the slimes, with a P20s loss of 23.6 percent. The pulp
was conditioned with 0.64 and 0.96 pound per ton of fatty acid and fuel
oil, respectively.
After a rougher and three cleaner flotations, the concentrate con-
tained, in percent, 26.2 P20s, 48.5 CaO, 1.4 MgO, 9.1 C02, and 2.5 acid-
insoluble material. The recovery of P2Os in the flotation feed was only
32.1 percent. The total recovery of the P20O was 24.5 percent.



14219-JENNINGS
A flotation sample was prepared as previously described from Jen-
nings composite sections. The MgO removal in the slimes was 88 per-
cent with a P0Os loss of 14 percent. The flotation feed was conditioned
with fatty acid and fuel oil in the amounts of 0.64 and 0.96 pound per ton
of ore, respectively.
After a rougher and four cleaner flotations, a concentrate was pro-
duced that contained, in percent, 24.2 P2Os, 46.1 CaO, 1.0 MgO, 13.5 C02,
and 6.2 acid-insoluble material. The P20s recovery from the flotation
feed was 54.0 percent. The total recovery of P20s was 46.5 percent.



14255-MIZELLE
As previously described, a flotation feed was prepared from Mizelle
composite sections. The MgO removal in the slimes was 86.9. How-
ever, 65 percent of the P2Os was lost in the slimes. After conditioning in
the amounts of 0.64 and 0.96 pound per ton of ore of fatty acid and fuel
oil respectively, a rougher concentrate was floated and cleaned six
times. The resulting concentrate contained, in percent, 29.0 P0Os, 44.7
CaO, 2.4 MgO, 9.8 CO2, and 6.1 acid-insoluble material. Furtherattempts
to lower the MgO content of the concentrate were not pursued because
of the high P2Os loss in the slimes.






BUREAU'OF GEOLOGY


Table 4.-Concentrate data of flotation studies of
composite sections of the Hawthorn Formation
Core No. Analyses, percent P,.O recovery,' Number of
and name PaO, CaO MgO CO, Insol percent cleaners
13765 Scott 3 ................... 29.0 50.1 1.0 7.9 4.5 76.9 3
13814 Ralford ................... 28.0 53.6 1.3 8.0 3.2 54.8 6
14179 Long Branch............... 26.2 48.5 1.4 9.1 2.5 32.1 3
14219 Jennings.................. 24.2 46.1 1.0 13.5 6.2 54.0 4
14255 Mizelle.................... 29.0 44.7 2.4 9.8 6.1 79.4 6
14280 Vames................... 28.9 49.0 1.0 9.0 5.1 82.3 6
'Recovery of PvO, from the flotation feed.



14280-VARNES
As previously described, a sample was prepared for flotation. The
MgO removal in the slimes was 72.2 percent with a P20s loss of 17.4 per-
cent. The reagent additions were 0.64 pound per ton of ore of fatty acid
and 0.96 pound per ton of ore of fuel oil. After a rougher and six cleaner
flotations, the resulting concentrate contained, in percent, 28.9 P20s,
49.0 CaO, 1.0 MgO, 9.0 CO, and 5.1 acid-insoluble material. P205
recovery from the flotation feed was 82.3 percent. The total recovery of
P20s was 68.0 percent.
Table 4 is a summary of the concentrate data for the flotation tests.
The results of the flotation studies of the composite sections were in
agreement with those predicted by the heavy liquid separation studies.



SEDIMENTATION OF SLIMES
In present Florida phosphate rock production, slimes disposal is a
significant problem. The volume of slimes produced is greater than the
volume of material mined. These slimes settle slowly, generally to about
11 percent solids in 30 days (Lamont et al., 1975). Thirty-day settling
tests were conducted on minus 400-mesh primary slimes from the Haw-
thorn samples. The percent solids were 7.2 to 10.9 after 5 days and 7.8 to
11.9 after 30 days. Subsequent settling was very slow.






REPORT OF INVESTIGATION NO. 94


CONCLUSIONS
Characterization studies of the Hawthorn Formation in northeast
Florida showed that phosphate was present in the formation. The
10-foot intervals ranged in P20s content from 0.1 to 19.9 percent with an
average of 2.6 percent. These studies revealed that the gangue minerals
associated with the phosphate were quartz, dolomite, and clay. Size
analyses indicated that most of the dolomite and clay minerals were
very fine grained.
Heavy-liquid separation showed that it should be possible to produce
a phosphate concentrate that contained, in percent, 26.3 to 32.0 P20s.
Subsequent flotation studies indicated that concentrates could be pro-
duced that contained, in percent, 24.2 to 29.0 P205, 44.7 to 53.6 CaO, 1.0
to 2.4 MgO, 7.9 to 13.5 CO2, and 2.5 to 6.2 acid-insoluble material. The
accompanying recoveries of phosphate from the flotation feed were
32.1 to 82.3 percent. Total recoveries of P205 from the core section
ranged from 24.5 to 68.0 percent.
Problems that would be associated with mining the Hawthorn Forma-
tion follow: Low-grade ore would have to be processed; no pebble-size
concentrate could be produced; slimes disposal techniques would
have to be improved; and MgO content of the concentrate would have to
be reduced.





56 BUREAU -OF GEOLOGY


REFERENCES
Cathcart, J. B., and R.A. Gulbrandsen. Phosphate Deposits In the U.S. Min. Res. Geol.
Survey. Prof. Paper 820,1973, p. 521.
Lamont, W. E., J. T. McLendon, L W. Clements, Jr., and I. L. Field. Characterization
Studies of Florida Phosphate Sllmes. BuMines RI 8089,1975, 23 pp.
Stowasser, W. F. Phosphate. BuMlnes, MCP, Jan. 1979,19 pp.
U.S. Comptroller General Report to the Congress. Phosphates: A Case Study of a
Valuable, Depleting Mineral In America, EMD-80-21, Nov. 30,1979, p. 1.
Zelers, Michael E. and J. M. Williams. Evaluation of the Phosphate Deposits of Florida
Using the Minerals Availability System, 1978, p. 57.





- REPORT OF INVESTIGATION NO.94


APPENDICES





REPORT O INVESTIGATION NO. 94


APPENDIX A
P20s analyses of core Intervals of the
Hawthorn Formation





80 BUREAU OF GEOLOGY






REPORT OF INVESTIGATION NO. 94 61


APPENDIX A
P20s analyses of core Intervals of the Hawthorn Formation

Core and Interval, feet POs, percent

Scott #1:
162-170 ............... 0.7
170-180 ............... 6.6
180-184 ............. 6.2
Scott #2:
80.5- 94 .............. 0.1
94 -104 ............. 0.2
115 -127 ....... ...... 0.8
127 -132.............. 0.5
132 -142 ......... 0.4
170 -192 .............. 1.6
192 -216 ............. 2.0
216 -240 ............ 2.0
Scott #3:
60- 69 ............... 0.1
75- 80 ............... 0.4
80- 92 .............. 0.2
92- 97 ............... 0.9
107-112 .............. 1.3
112-142 ............... 1.9
142-147 .............. 1.2
147-171 ............. 1.1
182-211 ............... 11.8
211-216 ............... 19.9
Ralford:
40- 48 ............... 3.6
48- 60 ............... 7.2
60- 70 ............... 3.5
70- 80 ............... 2.8
80- 90 ......... ... 4.9
90-100 .............. 5.0
100-110 ............... 4.6
110-120 .............. 4.9
120-130 ............... 1.8
130-140 ............ 5.3
148-160 .............. 2.0
160-170 .............. 0.7
170-200 ;............. 1.5
200-230 ............... 3.3
230-240 ............... 3.4
240-260 ............... 2.7
260-272 ............... 3.4
Long Branch:
60- 70 .............. 2.5
70- 80 ............... 4.9
80- 90 .............. 10.4
90-100 ............... 3.1
100-110 ................ 2.0
110-120 ............... 3.2
120-130 ................ 2.9
130-140 ............... 7.1
140-150 ............... 3.6
150-160 ............... 2.6
160-170 ............... 1.6






62 BUREAU OF GEOLOGY



APPENDIX A

PaOs analyses of core Intervals of the Hawthorn Formation-Continued


Core and Interval, feet


170-180
180-190
190-200
200-230
230-240
240-250
250-260
260-270
270-280
280-290
Fox Meadow:
73- 83
83- 93
93-103
103-113
113-123
123-133
133-143
143-153
153-163
163-173
173-183
183-193
193-203
203-213
213-223
223-233
235-243
243-253
253-263
263-273
273-283
283-293
293-303
303-313
313-325
Jennings:
60- 70
70- 80
80- 90
90-100
100-110
110-120
120-130
130-140
140-150
150-160
160-170
170-180
180-190
190-200
200-210
210-220
220-230
230-240


...............
...............,
...............
...............
...............
...............
...............
...............
...............



...............
...............
...............
...............*
...............,
...............
...............*
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............


...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............

...............
. .. ... ..... 4


PaO, percent

2.5
1.7
1.9
0.9
1.0
1.0
3.6
1.3
2.5
1.6

1.5
3.9
2.8
4.8
3.3
3.4
2.6
1.6
1.6
1.6
2.5
0.9
1.0
3.4
0.1
0.3
0.4
0.7
1.1
1.8
1.2
1.1
0.5
1.0
3.2


2.6
3.1
5.3
5.4
3.7
5.5
6.0
3.3
2.2
1.6
2.2
3.2
1.9
2.3
1.7
1.7
4.6
3.4






REPORT OF INVESTIGATION NO. 94


APPENDIX A
PaOs analyses of core Intervals of the Hawthorn Formation-Continued


Core and Interval, feet


260-270
270-290
290-300
300-310
310-320
320-330
330-340
340-360
360-370
370-380
380-390
390-400
400-410
410-420
420-431
Mizelle:


10- 20 ...............
20- 30 ...............
30- 40 ...............
40- 50 ...............
50- 60 ...............
60- 70 ...............
70- 80 ...............
80- 90 ...............
90-100 ...............
100-110 ...............
Varnes:
20- 30 ...............
30- 40 ...............
40- 50 ...............
50- 60 ...............
60- 70 ...............
70-140 ...............
140-167 ...............
Wainwright:
47.5- 56 ..............
56 72.5 ............
90 -100 ............
100 -110 ...........
110 -130 ........... .
130 -140..............
140 -150 ..............
150 -160 ..............
160 -170 ..............
170 180 ..............
180 -190 ..............
190 -210 ..............
210 -220 ..............
220 -230 ..............
230 -240 ..............
240 -250 ...............
260 -270 ...........
Valledujal:
120-130 ..............
130-140 ............


...............
...............
.... # ... .......
...............
...............
...............
....,.,.........
............,...
............,...
........o....,...
.....,..........
.......=....,..
.,........,,....
....,.......,o.,
. . ....... *


PlOs, percent

7.8
2.8
0.9
1.1
1.0
1.9
1.0
1.2
1.6
1.1
1.4
3.6
1.7
1.5
2.9

3.8
13.5
2.7
2.8
6.1
10.6
4.7
2.2
2.4
0.7

1.2
8.8
2.8
3.9
1.7
1.5
2.2

0.1
0.5
4.8
2,8
1.8
2.4
1.3
4.4
2.0
3.3
0.7
2.3
0.8
1.3
4.2
2.9
2.7--





64 BUREAU OF GEOLOGY


APPENDIX A
PaOs analyses of core Intervals of the Hawthorn Formation-Continued


Core and Interval, feet


140-150 ...............
150-160 ...............
160-170 ...............
170-180 ...............
180-190 ...............
190-200 ...............
200-210 ...............
210-220 ...............
220-230 ...............
Juniper Springs #1:
87- 97 ...............
97-108 ...............
Nichols:
11- 21 ...............
21- 31 ...............
31- 41 ...............
40- 50 ...............
50- 60 ...............
6n- 75 ...............
Moody #1:
80- 90 ...............
90-100 ...............
100-110 ...............
110-120 ...............
120-130 ...............
130-140 ...............
140-150 ...............
150-160 ...............
160-167 ...............
180-190 ...............
Merritt:
85 95..............
95 -105.5 ............
105.5-115 ..............
115 -126 ..............
126 -136 ..............
136 -147 ..............
East Palatka:
46- 56 ...............
56- 66 ............
66- 76 ...............
76- 86 ...............
86- 96 ...............
96-109 ................
Devils Elbow:
92-102 ...............
102-112 ...............
112-122 .............
122-132 ...............
132-142 ...............
142-152 ...............
152-162 ...............
162-172 .............
172-182 ...............
182-200 ...............


PO0s, percent
1.1
1.2
2.1
2.1
2.5
1.3
6.9
2.6
3.7

15.1
0.1

1.2
0.3
0.1
0.1
0.2
0.1

0.5
0.7
0.6
0.1
1.5
1.5
1.6
2.0
2.7
1.4

3.3
2.8
3.2
2.3
0.6
0.8

1.9
2.3
2.3
2.3
3.7
1.5

0.8
0.7
1.1
1.5
2.0
2.1
3.2
2.6
2.5
2.5


I





REPORT OF INVESTIGATION NO. 94


APPENDIX A

PaOs analyses of core Intervals of the Hawthorn Formation-Continued


Core and Interval, feet


P.O., percent


Parker Farms:
72- 90 ............... 0.5
90-110 ............... 0.3
110-120 ............... 2.9
120-130 ............... 1.1
130-140 ............... 1.1
140-150 ............... 1.0
150-160 ............... 1.5
160-171 ............... 2.1
171-181 ............... 2.2
181-191 ............... 2.2
191-201.5 ............... 1.3
201.5-211.5 ............ 3.1
211 -223 ............... 7.7
223 -233 .............. 1.3
233 -243 ............. 5.0


Kuhrt:
114-125 ,
125-135
135-145
145-155
155-165
165-175
175-185
185-193
195-205
202-220
230-240
240-250
250-260
260-270
270-280
280-290
290-300
300-310
310-320
320-330
330-340
340-350
350-360
360-370
370-380
380-390
390-403
Bostwick:
91-101
101-111
111-121
121-131
131-141
141-151
151-161
181-171
171-181
181-191


2.0
2.2
5.0
2.2
3.9
4.2
1.0
1.7'
1.8
1.7
3.0
2.0
1.4
1.4
0.3
0.5
3.6
1.8
3.4
3.4
1.6
1.2
1.5
1.4
1.2
2.1
2.2

0.2
1.9
2.5
1.9
1.7
1.9
0.8
2.6
0.6
2.2


...............
...............
...............
...............
...............
...............
...............
-..............
...............
...............
...............
...............
...............
...............
................
...............
... ..... .. .. .. .
. ..............






...............
..... o....... ..
. ..............







. .. .. .. ..... .. .

.... .. .. .. .. .. .
............. .. .
. ..............
...............
. .. .. .. ... .. .
. .. .. ... .. ..






66 BUREAU FO EOLOGY



APPENDIX A

P20s analyses of core intervals of the Hawthom Formation-Continued


Core and interval, feet

191-201 ...............
201-211 ...............
211-216 ...............


Miss J:
140-150
150-160
160-170
170-180
190-200
200-210
210-220
220-230
230-240
240-250
250-260
265-280
280-290
290-300
300-310
310-320
330-340
340-353
Atchenson:
78- 88
88- 98
98-108
108-118
118-128
128-138
138-148
148-163
163-173
173-183
183-193
193-200
Hall #1:
100-110
110-120
120-130
130-140
140-150
150-160
160-170
170-180
180-190
190-200
200-210
210-220
220-230


PaOs, percent

2.8
0.4
7.6


...............
...............
...............,
...............
...............,
...............
...............
...............
...............
...............
...............
...............


<0.1
<0.1
0.4
<0.1
2.1
0.3
0.7
<0.1
0.1
0.1
0.9
<0.1
<0.1
6.4
3.7
<0.1
3.8
1.9

7.0
1.7
0.4
0.1
0.9
1.6
4.5
1.0
<0.1
<0.1
<0.1
<0.1

6.5
<0.1
3.7
3.9
1.6
0.2
<0.1
<0.1
0.2
1.3
0.6
0.8
<0.1


...............
...............
...............
...............
...............
...............
...............
...............
...............
...............


...............,
...............
...............
...............
...............
...............
...............
...............
...............
...............
...............





REPORT OF INVESTIGATION NO. 94


APPENDIX B
Sieve analyses of composite sections of the
Hawthorn Formation





68 BUREAU OF GEOLOGY










Hawthorn Formation Drill Core
Well No. 13765, scot #3
Ore Number 0
Interval in Feet 182.0 to 216.0


Screen St Analysis
Weight
Grams Perent Pa0i
7.60 1.7 1240
4.60 1.0 9.30
13.90 3.1 670
26.70 6.0 10.00
5810 13.0 204
8850 19. 24.70
8590 19.3 22.00
5840 13.1 1680
17.80 4.0 740
17.50 3.9 480
67.20 15.1 1.80
44620 100.0 1586
16.70


CaO
33.70
17.50
11.60
15.90
33.90
40.90
36.90
3&90
1340
9.70
9.20
7.29
27.70


Analyses, Percent
MgO CO,
11.70 2320
1.70 600
0.70 300
0.70 3.70
0.80 6.70
0.90 7.90
0.80 7.10
090 6.10
1A4 5.30
3.30 8.50
9.00 22.70
2.38 9.34
250 9.70


Insol PO.i
13.70 1.3
57.70 0.O
7520 13
61.00 38
27.70 18.7
1580 30.9
24.60 26.7
3L70 13.9
61.50 1.9
68.40 1.2
55.30 1.7
3857 100.0
3380


Distribution, Percent
CaO MgO CO.
2.1 .4 4.2
0.7 0.7 0.7
1.3 0.9 1.0
35 1.8 2.4
152 4.4 9.3
2.7 75 16.8
25.3 6.5 14.6
12.7 5.0 85
2.0 2.3 2.3
1.4 5.4 3.8
5.1 57.1 36.0
100.0 100.0 100.0


Product
3X14
14X20
20 X 28'
28X935
35X48
48X65
65X100

200X 400
-400 Mesh
Compoeste
Head Sample


0;







z




z
z


Insol
0.6
1.6
64
10.0
9.9
8.
13.0
13.1
6.7
7.3
22.
100.0



















Hawthorn Formation Drill Core
Well No. 13814, Ralford
Ore Number 0
Interval in Feet 40.0 to 120.0


Screen Size Analysis
Weight
Gramr Percent POi
29.90 69 14.80
17.90 4.1 1300
27.40 63 10.00
32.20 7.4 8.10
67.30 15.5 6.30
57.90 134 440
4220 9.8 3.60
1020 2.4 4.30
5.50 1.3 3J0
23.30 5.4 1.50
119.00 27.5 1.30
432.80 100.0 5.30
5.00


CaO
42.70
27.40
2120
16.10
8.20
7.90
6.90
10.80
18.90
24.20
23.90
18.00
26.20


Analyses, Percent
MgO CO. Insol
8.40 17.80 15.30
6.30 15.20 30.50
5.10 1220 44.40
3.80 8-30 55.20
2.10 520 68.40
1.30 3.30 76.10
1.30 4.50 73.00
3.30 7.50 69.60
9.40 19.60 42.40
18.10 35.70 14.80
17.90 33.70 19.40
.17 16.55 45.47
7.80 15.10 45.70


P.O.10
19.3
10.1
11.9
11.4
18.5
11.1
6.8
1.9
09
1.5
8.8
100.0


Distribution, Percent
CaO MgO COi
16.4 7.1 74
6.3 32 3.8
7.5 4.0 4.7
6.7 3.5 3.7
7.1 4.0 4.9
5.9 2.1 2.7
3.7 14 2.6
1.4 1.0 1,1
1.3 15 1.5
7.2 11.9 11.6
38.5 0.3 58.0
100.0 100.0 100.0


Product
3X14
14X20
20 X 28
28 X 35
35X48
48 X85
65 X 100
100 X 150
150 X200
200 X400
-400 Mesh
Composite
Head Sample


Insol
2.3
28
6.2
9.0
23.4
224
15.7
3.6
1.2
1.7
11.7
100.0













Hawthorn Formation Drill Core
Well No. 14179, Long Branch
Ore Number 0
Interval in Feet 70.0 to 90.0

Screen Size Analysis
Weight Analyses, Percent Distribution, Percent
Product Grams Percent P.Oi CaO MgO CO* Insol PiO0 CaO MgO COi Insot
3X14 94.70 20.6 17.70 40.50 4.90 11.50 17.10 50.9 40.9 15.6 18.6 8.0
14X20 20.20 4A 15.80 34.80 5.10 10.40 22.00 9.7 75 3.5 3.6 2.2
20X28 18.70 4.1 9.90 28.50 6.10 1200 35.80 5.6 5.7 3.8 3.8 33
28X35 25.30 5. 7.80 23.60 5.30 10.50 46.80 6.0 6.4 4.5 4.5 5.9
35 X 48 41.00 8.9 640 17.90 3.00 5.70 63.80 8.0 7.8 4.1 4.0 13.0
48 X 65 60.0 13.1 3.70 9.70 1.60 3.10 79.60 6.8 62 3.3 3.2 232
65 X 100 61.70 13.4 2.40 8.70 1.60 2.40 83.80 4.5 5.7 3.3 2.5 25.6 0
100 X 150 16.00 35 2.90 8.70 4.80 9.50 63.70 1.4 1.5 2.6 2.6 5.0
150 X200 1050 2.3 3.30 17.90 950 18.40 37.40 1.0 2.0 3.3 3.3 1.9
200 X400 30.70 6.7 1.80 27.60 14.90 29.40 19.60 1.7 9.0 15.4 15.4 3.0
-400 Mesh 80.40 17.5 1.80 8.50 15.00 28.10 20.50 4.4 7.3 40.6 38.5 8.2
Composite 459.70 100.0 7.16 2041 6.47 12.76 43.90 100.0 100.0 100.0 100.0 100.0
Head Sample 7,00 24.10 6.50 12.60 43.50


















Hawthom Formation Drill Core
Well No. 14219, Jennings
Ore Number 0
Interval In Feet 80.0 to 130.0


Saren s Analys
Weight
Gramn Prcnt PsO$ Ceo
42.0 9 21.00 390
15.10 3 15.00 34.70
23.10 5.3 .0o 2120
32.10 7.4 6.70 1740
a&20 14 4.50 1060
70.0 1.2 2J0 7.70
80M 2104 1J0 &80
1830 4.2 1.30 .10
6.20 1A 2.00 9.9
10.30 2A 10 17A40
84.0 14A 1.60 .1u0
43330 100I.O 8 1517
530 1590


Analyes, Pwcent
MgO CO, InWd
2.10 m80 17.0
240 7.0 3280
220 840 a20
1.0 4.10 8M40
08O 2.30 740
0.Q0 140 87.30
0.50 050 0.10
10O 1.90 820
4.0 6.10 67.50
89O 1440 44.30
10.00 14.60 4040
2.M 4.91 6.18
3.10 450 1 70


PAO.
3.2
9.7
8,8
92
122
84
0.8
1.0
OJ8
44
100.0


Distrbutlon, Porct
CaO MgO CO,
25. 7.7 13S.
8.0 3.1 A.4
75 44 7.0
8 4 6.2
102 44 .8
82 3U 46
9.2 8 2.1
14 2.6 1.
0.9 2.3 1
2.7 &8 7.0
17.8 8.7 439
100.0 100.0 100.0


Product
3X14
14X20
20X28
28X36
35X48
58X100
100X 150
160X200
200X400
-400 MUh
Compoaote
HedSnmple


IMO
2.
1.7
4.3
74
17.3
21.3
27.8
55
15
1.8
9.0
100.0














Hawthorn Formation Drill Core
Well No. 14255, Mizelle
Ore Number 0
Interval in Feet 10.0 to 80.0


Screen She Analysis
Weight
Grms Percent PiOs CaO
25.0 54 17.60 3500
690 1.9 1300 22.30
1650 36 6.90 11.80
3060 80 3.70 5.50
13.40 303 4.20 580
30.70 6.7 480 6.30
3740 8.1 5.40 7.30
29.50 .4 5.0 8.00
990 22 5.80 7.70
16.30 3.6 800 12.70
10.20 238 7.50 13.80
46940 100.0 .35 10.38
7.00 14.10


Analyses, Percent
MgO CO, Insol
820 1820 11.00
4.0 9.70 .7.70
2.20 5&20 7.00
070 0.10 840
0.40 0.10 7840
040 0.10 77.40
030 0.10 75.10
050 0.10 74.50
050 0.10 7600
2.10 020 5560
3.30 0.40 5570
1.74 1.53 67.33
1.80 280 66.10


PlO*
15.1
4.0
3.9
4.6
20.1
49
6.9
5.9
2.0
45
28.1
100.0


Dsrbuton, Percnt
CaO MgO COa
183 2.5 648
4.2 1 123
4.1 45 122
42 32 05
17.0 7.0 2.0
4.1 1.5 04
5.7 1A 05
4.9 1 0.4
16 0. 0.2
4.3 4.3 0.5
31 45.0 6.2
100.0 100.0 100.0


Product
3X14
14X20
20X28
28X35
36X48
48866
65 100
100X 150
150 X 200
200 X400
-400 Mesh
Composite
Hed Sample


U,

:a



-I





U"
:ii









z


Insol
0.8
1.1
38
10.2
313
7.7
9.1
7.1
24
2.9
19.7
100.0


















Hawthorn Formation Drill Core
Well No. 14280, Varnes
Ore Number 0
Interval in Feet 30.0 to 60.0


Screen Size Analysis
Weight
Grams Percent PIOi CaO
93.80 19. 110*0 32.60
20.70 4A 990 30.60
19.70 42 6.90 24.90
4680 99 0.20 15.00
5230 11.0 4.90 10.60
9.90 2.1 3.70 1080
6040 12.6 4.00 9.30
3430 72 3.80 880
12.70 2.7 3.80 11.40
31.10 6.6 2.30 24.90
92.20 19.5 2.30 21.50
473.90 100.0 5.53 19.65
550 25.70


Analyses, Percent
MgO COs Insol
11.40 25.00 15.0
10.80 22.70 19A0
6.20 16A0 40.50
3A40 0.0 61.10
1.50 5.00 77.30
1.0 5.00 7780
1.10 320 77.10
1.70 420 79.0
4.20 8.00 66.70
14.10 2820 22.90
13.60 2.70 29A0
7.47 15.30 4645
7.40 15.00 4520


Distribution, Percent
Pa0O CaO MgO CO, Insol
37.9 328 302 32.3 6.7
7.8 .8 6.3 6.5 1.
5.2 53 35 4. 3.
11.1 7.5 45 03 13.0
98 6.0 22 3. 18.4
1A 1.2 05 0.7 35
9.2 6.0 1.9 2.7 21.2
5.0 3.2 1.6 2.0 12A
1.8 1. 1.5 14 39
2.7 83 124 12.1 3.2
8.1 213 35A 339 123
100.0 100.0 100.0 100.0 100.0


Product
3X14
14X20
20X28
28 X 35
35 X 48
48X65
65X100
100X 150
150X200
200X400
-400 Mesh
Composite
Head Sample


0
C



O
"1



0I
S3



t*





REPORT OF INVESTIGATION NO, 94


APPENDIX C
Petrographic analyses of composite sections
of the Hawthorn Formation





76 -. BUREAU OFGEOLOGY












PETROGRAPHIC ANALYSES
Core No.: 13765 m
Name: Scott #3
County: St. Johns
Core section: 182-216 feet O
.:


Percent of grains at each size fraction
Scen size Weight- Carbonate-fluorapatite Aggregates
fraction percent Free Locked Dolomite Quartz clay-dolomite Clay Other Total


Minus3plus14 ........... 1.7 20 0 77 3 0 0 0 100
Mlnus14plus20 .......... 1.1 11 0 16 37 36 0 0 100
Mlnus20plus28 .......... 3.1 7 0 6 56 31 0 0 100
Mlnus28plus35 ......... 6.0 42 0 0 54 3 0 1 100
Mlnuas3plus48 .......... 13.0 54 0 0 39 7 0 0 100
Minus48plus65 .......... 19.8 52 0 0 39 7 0 2 100
Minus65plus10 ......... 19.3 57 0 0 24 16 0 3 100
Minus 100plu 150 .... ... 13.1 43 0 0 38 17 0 2 100
MinusIS10 plu 400 ....... 4.0 27 0 0 58 13 0 2 100
Minus200plus400 ........ 3.9 16 0 44 38 0 0 2 100
Mlnus400' ............... 15.0 Minor 0 Minor Moderate 0 Major 0 -
Clay content of this fraction made a grain count inaccurate.


O
0
0 '
z^


--
















PETROGRAPHIC ANALYSES

Core No.: 13814
Name: Ralford
County: Bradford
Core section: 40-120 feet
Percent of grains at each size fraction
Screen se Weight- Casbonate-fluorapatlte Aggregates Heavy
fraction percent Free Looked Dolomite Quartz claydolomite mineral Total
Mlnus3plus14 ........... e 37 0 0 3 60 0 100
Minusl4plus20 .......... 4.1 23 5 0 12 60 0 100
Minus20plus 2 .......... 6.3 21 0 0 37 42 0 100
Minus28plus3 .......... 7.4 25 0 0 48 27 0 100
Minus35plus48 ......... 15.5 20 0 0 65 21 0 100
Minus48plus5 .......... 13.4 12 0 0 78 11 1 100
Minus 6plus100 ........ 9.8 13 0 0 74 12 1 100
Minus100plus150 ....... 2.4 16 0 35 48 0 1 100
Minus150plus200 ........ 13 11 0 19 48 22 2 100
Minus200plus400 ....... 5.4 3 0 54 9 33 1 100
Minus400 ............... 27.5 3 0 74 10 12 1 100












PETROGRAPHIC ANALYSES

Core No.: 14179
Name: Long Branch
County: Clay
Core section: 70-90 feet

Percent of grains at each size fraction
Screen size Weight- Caronate-fluorapatfte Aggregate Heavy Dolomite
fraction percent Free Locked clay-dolomite Quartz Calcite mineral rhombs Total
Mlnus3pus14 ........... 205 0 78 23 1 0 0 0 100
Minus14plus20 .......... 4. 29 6 62 2 1 0 0 100
Mkius20plus28 .......... 4.1 19 3 66 11 1 0 0 100
M1nua28plus35 .......... 55 20 0 56 24 0 0 0 100
Minus35plus48 ......... 8.9 13 0 43 44 0 0 0 100
Mlnus48plus65 .......... 13.2 14 0 38 47 0 1 0 100
Minus66plus100 ......... 13.4 5 0 28 66 0 1 0 100
MInus l0plus150 ........ 35 5 0 51 43 0 1 0 100
Mlnus150plus200 ....... 2.3 13 0 66 21 0 0 0 100
Minus200plus400 ........ 6.7 6 0 33 9 0 0 52 100
Mlnus400................ 175 5 0 30 10 0 0 55 100















PETROGRAPHIC ANALYSES
Core No.: 14219
Name: Jennings
County: Clay
Core section: 80-130 feet
Percent of grains at each size fraction
Scmn sze Weight- Carbonate4lorapate Aoon"ate
fraction percent Fre Locked Dolomite Quartz Other Calcite claydolomlts Total
Minus3pl kl4 ........... 94 s0 0 0 1 0 4 5 100
MMukl4plus20 .......... 5 23 23 0 12 0 5 37 100
Mlnus20plus2 .......... U 14 5 0 29 0 5 47 100
Minus28plu36 .......... 7A 19 0 0 49 0 1 31 100
Minus35plus48 .......... 146 13 0 0 8 0 1 17 100
Mknus48plusS .......... 162 11 0 0 72 0 1 16 100
M sipnukaSp lOs ......... 204 4 0 0 79 1 1 15 100
MiuMl00plus 50 ....... 42 3 0 0 S6 2 1 38 100
Mus150 plus200 ....... 1. 5 0 0 41 3 0 51 100
Mius200pluk400 ....... 2A4 0 10 31 3 0 51 100
Mlnu400' .............. 148 Minor 0 Dominant Moderate 0 0 Moderate -
' Clay content of this fraction made a grain count Inaccurate.











3
m
311
I
a
B


PETROGRAPHIC ANALYSES
Core No.: 14255
Name: Mizelle
County: Bradford
Core section: 10-80 feet
Parent of grains at each skee fraction
Sceen sze Weight- Carbonaeuoraute Aggrates
fraction percent Free Locked Dolomite Qurtz Other sydolomte Sandrock Clay Total
Minus3plusl4.............. 54 43 0 0 4 0 48 5 0 100
Mintua4phla20............. 1.9 19 0 14 28 0 30 0 0 100
Minus20plus28 ............. 3.6 8 0 8 56 0 28 0 0 100
Minu28plus36 ............. 8.0 12 0 0 77 1 0 0 10 100
MInus36plus48 ............ 30.4 12 0 0 80 0 0 0 8 100
Minus48plu 66............. 6.7 15 0 0 77 0 0 0 8 100
MinueSplus100 ............. 8.1 15 0 10 75 0 0 0 0 100
Minu100lplus150............ .4 17 0 0 83 0 0 0 20 100
Mlnus150plus200 ........... 2.2 15 0 31 51 3 0 0 0 100
Mlnus200plus400 ............ 3.5 13 0 6 22 1 0 0 58 100
Minus400 ................... 23 20 0 5 30 0 0 0 45 100















PETROGRAPHIC ANALYSES
Core No.: 14280
Name: Vames
County: Bradford
Core section: 30-60 feet
Percent of grains at each size fraction
Screen size Weight- Carbonate-luorapatite Aggregates Aggregates Looked
fraction percent Free Locked Dolomite Quartz Other clay.dolomite claysand dolomitseand Total
Minu3 plus 14............... 19.7 29 0 0 1 0 70 0 0 100
Mlnusl4plus20 ............. 4.4 4 9 0 4 0 45 5 33 100
Minus20plus28 ............. 4.1 8 4 0 19 0 57 6 6 100
Minus28plus35.............. 10.2 15 0 0 36 0 48 3 0 100
Mlnus35plus48 ............. 11.0 14 0 0 66 0 18 2 0 100
Minus48plus6 .............. 2.1 14 0 0 64 3 19 0 0 100
Minus6plusl00 ............. 12.7 8 0 0 72 2 18 0 0 100
MinuelOpluaO1 ........... 7.2 12 0 0 49 1 38 0 0 100
Mlnus150plus200 ........... 2.7 13 0 0 221 37 27 0 100
Minua200plus400 ........... 6.5 8 0 63 12 0 0 17 0 100
Minus400 .................. 19.4 7 0 60 13 0 0 20 0 100
,. .. 00...... .


0
C



0

0
II
*<





REPORTOF INVESTIGATION NO. 94


APPENDIX D
Heavy liquid separation analyses of composite
sections of the Hawthorn Formation





84 BUREAU OF GEOLOGY





Hawthorn Formation Drill Core
Well No. 13765, Scott #3 St. Johns County
Ore Number 0
Interval in Feet 182.0 to 216.0


Product
moat 268
.SA68-F2.75
82.76-F/285
8/2.5-FM293
Sink 293
Total


Product
Float 288
82.68-F/2.75
812.75-F/2.85
'82.85-F/2.93
Sink 2.93
Total'


Product
Float 2.68
S/2.68-F/2.75
82.75-F/2.85
82.85-F/293
Sink 2.93
Total


Product
35/150 Mesh
1501400 Mesh
-400 Mesh Prl
-400 Mesh Sec
Total
Head Sample


Weight
Percent
33A
4.0
15.0
47A8
0.0
100.0

Weight
Percent
47.7
0.0
11.7
40.5
0.0
100.0

Weight
Percent
36.0
33
144
46.3
0.0
100.0

Weight
Percent
59.8
13.6
18.9
7.7
100.0
0.0


Composite Analysis
Analysis, Percent
CaO MgO
25.85 0.64
21.73 0.70
49.20 0.88
20.60 4.37
29.30 0.98
27.70 2.49


Screen Size, Mesh Minus 35, Plus 150
Analysis, Percent
PlOs CaO MgO
0.71 1;02 0.09
7.32 9.93 0.35
28.10 40.50 1.64
28.00 40.00 0.73
0.00 0.00 0.00
18.07 25.85 0.84

Screen Size, Mesh Minus 180, Plus 400
Analysis, Percent
PsO, CaO MgO
0.78 147 0.22
0.00 000 0.00
25.60 3430 2.51
28.70 41.90 0.74
0.00 0.00 0.00
15.02 21.73 0.70

Screen Size, Mesh Minus 35, Plus 400
Analysis, Percent
PSO, CaO MgO
0.73 1.13 0.12
7.32 9.93 0.35
27.72 39.57 1.77
28.11 40.31 0.73
0.00 0.00 0.00
17.51 25.09 0.65


COt
0.11
0.21
17.00
21.50
0.00
1283


COs
0.15
0.00
22.80
16.60
0.00
9.48


COO
0.12
0.21
17.87
20.70
0.00
1221


COB
12.83
9.48
34.30
3.90
15.74
9.72


Insol
96.64
74.78
4.56
212
0.00
36.96


Insol.
95.26
0.00
5.84
4.50
0.00
48.05


Insol
96.30
74.78
4.72
2.56
0.00
39.02


Insol
36896
48,05
2.44
49.78
3293
33.60


1.3
1.8
23.3
73.8
0.0
100.0


P20.
2.5
0.0
199
77.6
0.0
100.0


P*0o
1.5
.1.4
22.8
74.3
0.0
100.0



74.1
14.0
4.9
7.0
100.0


CaO
52.
10.1
31.7
5.4
100.0


Distribution, Percent
MgO
39.1
9.7
16.7
34.5
100.0 1


it


Distribution, Percent
CaO MgO
1.3 4.7
1.5 2.2
235 38.5
73.7 54.5
0.0 0.0
100.0 1000

Distribution, Percent
CaO MgO
3.2 15.0
0.0 0.0
185 42.0
78.3 43.0
0.0 0.0
100.0 100.0 1

Distribution, Percent
CaO MgO
1.6 6.8
1.3 1.7
22.7 39.3
74.4 52.2
0.0 0.0
100.0 100.0 1


CO,
0.3
0.0
19.9
79.8
0.0
00.0


CO.
0.8
0.0
28.1
71.1
0.0
00.0


CO.
0.3
0.1
21.1
78.5
0.0
00.0


COB
48.7
8.2
41.2
1.9
10.0


18.07
18.02
3.73
13.30
14.58
16.70


Insal
87.3
8.1
1.9
2.7
0.0
100.0


Insol
94.8
0.0
14
4.0
0.0
100.0


Insol
89.0
6.3
1.7
3.0
0.0
100.0


Insol
67.1
19.9
14
11.5
100.0


m
M


O
0
"1
.0





*


z
z


2








Hawthorn Formation Drill Core
Well No. 13814, Ralford Bradford County
Ore Number 0
Interval In Feet 40.0 to 120.0


Screen Size, Mesh Minus 35, Plus 150
Analysis, Percent
P,0o COa MoO
0.44 1.30 0.38
5.02 15.10 4.40
15.10 38.90 8.95
28.40 45.30 1,45
26.70 43.80 0,74
6.04 12.24 1.51

Screen Size, Mesh Minus 150, Plus 400
Analysis, Percent
PIO, CaO MgO
0.63 6.18 3.46
0.00 0.00 0.00
5.38 33.00 15.70
26.10 44.40 1.70
0.00 0.00 0.00
6.54 22.46 7,77

Screen Size, Mesh Minus 35, Plus 400
Analysis, Percent
P.O, CaO MgO
046 1.89 0.75
5.02 15.10 4.40
10.52 38.12 12.13
26.34 45.12 1.50
25.70 43.80 0.74
6.12 13.99 2.58


Product
Float 2.68
82.68-PF/2.75
8/2.75-.P2.85
S/2.85-P/2.93
Sink 2.93
Total


Product
Float 2.688
8/2.68-F/2.76
812.75-P/2.5
8/2.85-F2.93
Sink t.93
Total


Product
Float 2.68
812.88-F/2.75
82.756Fl2.85
812.85-F/2.93
Sink 2.93
Total


Product
35/150 Mesh
1501400 Mesh
-400 Mesh Pri
-400 Mesh Sea
Total
Head Sample


Weight
Percent
70.0
5.5
8.8
13.3
2.4
100.0

Weight
Percent
46.2
0.0
37.6
16.2
0.0
100.0

Weight
Percent
85.9
4.6
13.8
13.8
2.0
100.0


Weight
Percent
49.4
10.3
33.8
6.5
100.0
0.0


COi
0.15
8.30
20.80
16.60
10.40
4.84


COi
3.90
0.00
33.70
14.00
0.00
16.74


COi
0.60
8.30
26.88
15.99
10.40
6.88


COi
4.84
16.74
30.70
22.20
15.93
15.06


Insol
92.90
60.18
7.24
3.84
11.84
69.77


Insol
78.82
0.00
5.18
4.74
0.00
39.13


Insol
91.20
60.18
6.27
4.02
11.84
64.43


Insol
69.77
39.13
20.24
27.98
47.16
45.66


Distribution, Percent
CaO MgO
7.4 17.6
86.8 16,1
28.0 52.3
49.2 12.8
8.6 1.2
100.0 100.0


6.1
4.6
22.0
,8.1
10.2
100.0



4.5
0.0
30.9
64.6
0.0
100.0


P3O0
5.0
3.6
23.7
59.4
8.3
100.0


PaO.
67.7
15.3
8.6
8.4
100.0


Distribution, Percent
MgO
20.5
0.0
76.0
3.5
0.0
100.0

Distribution, Percent
MOO
19.2
7.6
64.6


CO.
2.2
9.4
37.8
46.4
5.2
100.0


COO
10.8
0.0
75.7
13.6
0.0
100.0


CO8
5.8
5.3
53.8


8.0 32.1
0.6 3.0
100.0 100.0


Distribution, Percent
CaO MgO CO.
33.3 9.4 15.0
12.7 10.1 10.8
45.1 71.2 85.1
8.9 9.3 9.1
100.0 100.0 100.0


Composite Analysis
Analysis, Percent
CaO MgO
12.24 151
2246 7.77
24.20 18.70
24.70 11.40
18.14 7.93
26.23 7.82


CaC
12.1
0.C
85.3
32.C
0.0
100.0


CaO
8.9
4.8
35.6
44.5
6.2
100.0


Insol
93.2
4.8
0.9
0.7
0.4
100.0


Insol
93.0
0.0
5.0
2.0
0.0
100.0


Insol
93.3
4.1
1.3
0.9
0.4
100.0


Insol
73.1
8.5
14.5
3.9
100.0


I


I






Hawthorn Formation Drill Core
Well No. 14179, Long Branch Clay County
Ore Number 0
Interval in Feet 70.0 to 90.0


Screen Size, Mesh Minus 35, Plus 150
Analysis, Percent
P.O. CaO MgO
0.49 5.90 1.14
1.58 24.34 5.80
11.58 44.13 10.00
28.26 45.75 1.23
27.51 42.24 0.90
8.53 19.35 1.87

Screen Size, Mesh Minus 150, Plus 400


Product
Float 2.68
82.68-F/2.75
S/2.75-F/2.85
S/2.85-F12.93
Sink 2.93
Total


Product
Float 2.68
82.68-F/2.75
8/2.75-F12.85
S12.85-F/2.93
Sink 2.93
Total


Product
Float 2.68
S2.68-F/2.75
.S2.75-F12.85
S/2.85-F/2.93
Sink 2.93
Total


Product
351150 Mesh
150/400 Mesh
-400 Mesh Pri
- 400 Mesh Sec
Total
Head Sample


Weight
Percent
63.1
4.5
5.8
21.0
5.8
100.0

Weight
Percent
45.0
12.6
16.2
23.4
2.8
100.0

Weight
Percent
58.8
6.4
8.3
21.6
4.9
100.0


Weight
Percent
53.9
16.6
21.7
7.8
100.0
0.0


Analysis, Percent
MgO
6.53
15.60
16.65
2.09
0.86
8.11


Screen Size, Mesh Minus 35, Plus 400


P3O0
0.70
1,29
7.57
28.10
26.59
8.50


Analysis, Percent
CaO MgO
7.97 2.11
31.35 10.34
44.15 13.08
46.09 1.45
41.18 0.89
22.36 3.35

Composite Analysis
Analysis, Percent
CaO MgO
19.35 1.87
31.94 8.11
34.32 13.57
38.89 10.44
26.06 6.11
24.13 6.54


CO2
2.32
18.10
22.97
5.22
3.99
4.93


CO0
11.01
38.13
34.25
7.04
3.83
16.81


COg
3.88
26.45
28.19
5.69
3.97
7.76


CO.
4.93
16.81
26.98
20.96
12.94
1263


Insol
89.64
49.06
11.12
3.41
6.56
60.50


Insol
59.98
7.09
3.41
2.11
22.95
29.57


Insol
84.30
29.63
7.55
3.00
8.75
53.22


Insol
60.50
29.57
19.87
21.02
43.47
43.53


3.6
0.8
7.9
69.6
18.1
100.0


P.O,
8.8
1.5
5.6
77.2
6.9
100.0


P.O.
4.8
1.0
7.4
71.3
15.5
100.0


P.O.
62.1
18.8
10.6
8.5
100.0


CaC
19.2
5.7
13.2
49:7
12.2
100.0


Distribution, Percent
MgO
38.5
S 14.0
31.0
13.8
2.7
100.0 1


Distribution, Percent
CaO MgO
24.5 36.2
15.6 24.2
22.4 33.3
34.5 6.0
3.0 0.3
100.0 100.0 1


CaO
21.0
9.0
16.5
44.4


Distribution, Percent
MgO
37.0
19.8
32.6
9.3


9.1 1.3
100.0 100.0


CaO
40.0
20.4
28.8
11.0
100.0


Distribution, Percent
MgO
16.5
22.0
48.2
13.3
100.0


CO,
29.7
16.5
27.0
22.3
4.5
100.0


COt
29.5
27.1
33.0
9.8
0.6
00.0


Insol
93.5
3.6
1.1
1.2
0.6
100.0


Insol
91.3
3.0
1.8
1.7
2.2
100.0


COi Insol
29.5 93.2
21.9 3.6
30.3 1.2
15.8 1.2
2.5 0.8
100.0 100.0


COi
20.5
21.6
45.3
12.6
100.0


Insol
75.0
11.3
9.9
3.8
100.0 0Q
04


P.Oo
1.64
0.96
2.90
27.64
20.64
8.37


CaO
17.38
39.48
44.18
47.10
34.32
31.94


1







Hawthorn Formation Drill Core
Well No. 14219, Jennlngs Clay County
Ore Number 0
Interval In Feet 80.0 to 130.0


Product
Float 2.6
12.6-F12.75
8/2.75F/2.85
Si.865-F/2.93
Sink 2.93
Total


Product
Float 288
8.68-FI2.75
812.76-FI2.M
82.85-FI2.93
8ink 293
Total


Product
Float 2.68
8/28-FI2.75
812.75-FI2.
8.85-FI2.93
Sink 2.93
Total


Product
356l50 Mesh
1501400 Mesh
-400 Mesh Pri
-400 Mesh Sec
Total
Head Sample


Weight
Percent
792
6.
3.0
10.2
2.0
100.0

Weight
Percent
63.
4.7
8.3
18.2
6.2
100.

Weight
Percent
77.0
5.6
3.7
11.3

100.0

Weight
Percent
67.8
11.2
16.1
4.9'
100.0
0.0


Composite Analysis
Analysis, Percent
CaO MgO
10.72 0.64
2180 345
21.97 9.52
24.14 5.80
14.43 2.64
1593 3.06


Screen Size, Mesh Minus 35, Plus 160
Analysis, Percent
PO, C10 MgO
0.37 3.50 0A4
2.47 21.08 0.84
21.79 4351 3.39
27.33 46.07 1.27
23.08 38.10 0.70
4.33 10.72 0.4

Screen Size, Mesh Minus 150, Plus 400
Analysis, Percent
PO. CaO MgO
0.85 8.93 2.87
0.94 44.18 6.38
11.49 45.29 1243
28.83 47.46 1.3
19.75 31.70 0.90
7.69 1.80 345

Screen Size, Mesh Minus 35, Plus 400
Analysis, Percent
PsOi CaO MgO
040 4.14 0.72
228 2389 1.61
18.56 44.07 6.23
27.67 46.39 1.29
22.08 36.18 0.76
4.79 1225 1.03


CO.
0.84
11.77
8.77
4.82
309
2.16


CO.
349
3329
25.22
6.51
2.97
7.03


CO.
1.17
1439
13.93
4.98
3.05
2.83


CO.
2.16
7.03
14.07
10.17
5.01
4.89


Insol
9465
02.93
12.07
3.38
19.38
79.548


Insol
80.81
1442
4.61
1.98
28.0
54.33


Insol
93.03
57.05
9.73
3.05
22.24
75.99


Insol
79.48
54.33
38.00
3849
68.04
66.72


CaO
25.9
11.0
122
43.8
7.1
100.0


Dlstrlbi


uilon, Percent
MgO CO* Insol
64A 316 94.2
73 30.5 44
15.9 12.2 0.5
20.2 22.8 04
2.2 2.9 0.5
100.0 100.0 100.0


P.O.
6.8
32
15.1
54.3
10.6
100.0


P.O.
64
0.6
124
68.3
13:3
100,0


P.O.
6.5
2.6
14.1
65.5
11.3
100.0



62.1
18.2
11.0
8.7
100.0


CaO
26.0
10.7
13.1
42.
7.
100.0


Distribution, Percent
MgO
54.
8.0
22.0
14.2
1.8
100.0


Distribution, Percent
CaO MgO
504 16.5
16. 14.6
24.5 58.1
8.2 10.8
100.0 100.0


CO.
31.5
222
20.8
144
2.2
100.0


CO,
31.7
27.8
18.0
19.9
2.6
100.0


CO,
2.2
16.7
45.2
9.9
00.0


4.33
7.69
3.24
841
4.73
5.29


Distribution, Percent
CaO MgO
26.1 562.
9.5 8.7
17.2 29.9
396 7.2
7. 14.
100.0 100.0


Insol
94.6

0.7
0.6
2.8
100.0


Insol
94.2
4.1
0.5
0.5
0.7
100.0


Insol
79.3
8.9
9.0
2.8
100.0


1





Hawthorn Formation Drill Core
Well No. 14255, Mizelle Bradford County
Ore Number 0
Interval in Feet 10.0 to 80.0


Screen Size, Mesh Minus 35, Plus 150
Analysis, Percent
P.O. CaO MgO
0.56 1.00 0.16
3.79 9.47 2.31
8.87 32.00 1260
30.50 45.60 0.66
3290 47.40 0.31
4.45 7.43 0.70

Screen Size, Mesh Minus 150, Plus 400


Product
Float 268
2.68-F2.75
82.75-FI2.85
S2.85-FI2.93
Sink 2.93
Total


Product
Float 2.66
82.68-F2.75
S2.75-F2.85
S285-F/2.93
Sink 2.93
Total


Product
Float 2.68
S2.68-F/2.75
S82.75-F/25
8285-FL2.93
Sink 2.93
Total


Product
35/150 Mesh
150/400 Mesh
-400 Mesh Pri
-400 Mesh Sec
Total
Head Sample


Weight
Percent
82.4
3.0
3.8
2.5
8.5
100.0

Weight
Percent
80.2
0.0
10.4
0.0
9.4
100.0

Weight
Percent
82.0
2.4
4.9
2.0
8.7
100.0

Weight
Percent
54A
12.3
27.3
8.0
100.0
0.0


Analysis, Percent
MgO
0.39
0.00
8856
0.00
0.43
1.27


Screen Size, Mesh Minus 35, Plus 400
Analysis, Percent
PO, CaO MgO
0.85 1.41 0.20
3.79 9.47 2.31
11.77 34.25 11.12
3050 45.60 0.66
3240 47.30 0.33
4,79 8.08 0.80


4.4
629
6.70
9.85
5.80
6.97


Composite Analysis
Analysis, Percent
CaO MgO
7.43 0.70
10.94 1.27
15.10 4.02
18.40 3.33
10.61 1.83
14.07 1.75


CO.
0.01
3.50
30.60
12.40
8.10
2.21


CO.
0.20
0.00
26.80
0.00
6.90
3.60


CO,
0.04
3.50
29.10
12.40
7.86
2.47


CO2
2.21
3.80
14.10
11.80
6.20
2.80


Insol
97.08
75.48
8AO
4.0
4.28
83.04


Insol
89.44
0.00
4.46
0.00
8.32
72.98


Insol
95.70
75.48
6.84
4.80
5.09
81.19


Insol
83.04
72.98
52.10
49.78
71.38
66.11


P2O.
10.4
2.5
7.2
17.1
62.8
100.0


P.O.
27.8
0.0
26.8
0.0
454
100.0


PO.s
14.6
1.9
11.9
13.0
58.6
100.0


P.O.
43.2
13.8
32.7
10.3
100.0


Distribution, Perce
CaO MgO
11.2 18.9
3.8 9.9
15.5 65.0
15.4 2.4
542 3.8
100.0 100.0


CaO
23.8
0.0

0.9
40.3
100.0


Distribution, Percen
MgO
24.5
0.0
72.3
0.0
3.2
100.0


nt


It


Distribution, Percent
Ca0 MgO
14.3 20.6
2.9 7.0
20.8 67.1
11.5 1.7
50.7 3.6
100.0 100.0 1

Distribution, Percent
CaO MgO
38.1 20.7
12.7 8.5
38 50.9
10.4 10.9
100.0 100.0 1


CO0
0.4
4.7
49.8
14.0
31.1
100.0


CO-
4.5
0.0
77.5
0.0
18.0
100.0


CO0
1.5
3.5
57.2
10.2
27.8
100.0


CO0
19A
7.1
62.1
114
00.0


P.O.
2.18
0.00
16.20
0.00
3040
6.29


CaO
3.25
0.00
37.70
0.00
46.90
10.94


Insol
96.3
2.7
0.4
0.2
0.4
100.0


Insol
98.3
0.0
0.8
0.0
1.1
100.0


Insol
96.7
2.3
0.4
0.1
0.5
100.0


Insol
633
12.8
19.9
4.2
100.0







Hawthorn Formation Drill Core
Well No. 14280, Varnes Bradford County
Ore Number 0
Interval In Feet 30,0 to 60.0


Product
Float 2.68
Sn2.6A8-P2.75
0S2.75-PF2.A5
8/2S5-FI2.93
Sink 2.93
Total


Product
Float 2.88
82.68-FI2.75
82.75-P2.85
12.5-FI2.93
Sink 2.93
Total


Product
Float 288
S2.88-F/2.75
8V.75-F2.85
812.5-FJ.93
Sink 2.93
Total


Product
35/150 Mesh
1501400 Mesh
-400 Mesh Pri
-400 Mesh Sec
Total
Head Sample


Weight
Percent
64.7
7.5
13.9
11.8
2.1
100.0

Weight
Percent
40.1
9.5
34.9
15.5
0.0
100.0

Weight
Percent
50.9
7.9
18.0
12.5
1.7
100.0

Weight
Percent
50.7
122
30.7
6A
100.0
0.0


Composite Analysis
Analysis, Percent
CaO MgO
12.98 2.37
21.73 9.10
2240 13.70
27.40 12.30
17.88 7.30
25.69 7.44


Screen Size, Mesh Minus 35, Plus 150
Analysis, Percent
PaOi CaO MOO
0.84 1.36 0.34
2.95 12.20 6.31
11.76 35.30 11.60
2740 45.70 1.03
25.70 42.10 0.72
8.04 12.98 2.37

Screen Size, Mesh Minus 150, Plus 400
Analysis, Percent
PsO, CaO MgO
0.48 244 1.54
1.18 26.90 17.70
26d 32.10 18.80
26.20 45.10 1.54
0.00 0.00 0.00
5.29 21.73 9.10

Screen Size, Mesh Minus 35, Plus 400
Analysis, Percent
PiO. CaO MgO
0.62 1.50 0.50
2.54 15.63 8.20
8.33 34.09 14.31
27.11 4556 1.15
25.70 42.10 0.72
5.90 14.68 3.67


CO*
0.10
16.90
29.30
17.00
1240
7.67


COg
1.05
33.00
33.90
15.10
0.00
17.73


CO,
0.22
20.6
31.03
16.54
12.40
9.62


COs
7.47
17.73
26.10
26.30
15.75
15.02


Insol
96810
61.56
4.76
2.00
10.86
67.92


Insol
88.98
11.20
2.66
4.48
0.00
37.57


Insol
94.92
4920
3.97
2.80
10.86
62.03


Insol
67.92
37.57
26.08
20.72
48.35
45.20


Distribution, Percent
CaO MgO
68 9.3
7.0 16.8
37. 68.1
416 5.1
64 0.7
100.0 100.0

Distribution, Percent
CaO MgO
4.5 6.8
11.8 18.5
51.5 72.1
32.2 2.
0.0 0.0
100.0 100.0 1

Distribution, Percent
CaO MgO
6.1 8.1
8.4 17.8
41.8 70.1
38.9 39
4.8 03
100.0 100.0 1


PoO,
6.9
3.7
27.0
53.5
8.9
100.0


P.O.
3.5
2.1
176
768
0.0
100.0


PRO0
6.3
3.4
25.4
57.5
7.4
100.0


PsO.
54.8
11.5
25.9
7.8
100.0


Distribution, Percent
MgO
16.4
15.2
57.6
10.
100.0 1


CO.
0.8
16.5
53.1
26.2
3.4
100.0


CO,
2.4
17.7
66.7
13.2
0.0
I00.0


CO.
1.4
16.9
58.0
21.5
2.2
00.0


COs
24.7
13.7
50.
10.7
00.0


B


PO.6
6.04
529
4.71
6.82
5.59
5.47


CaC
36.8
14.9
38.5
9.8
100.0


91.
6.8
1.0
0.4
0.3
100.0


Insol
928
2.8
2.5

0.0
100.


Insol
91.7
6.3
1.2
0.5
0.3
100.0


Insol
71.2
9.5
16.6
2.7
1000


1,










FLRD GEOLOSk ( IC SUfRiW


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