Title Page
        Page i
        Page ii
    Letter of transmittal
        Page iii
        Page iv
    Table of Contents
        Page v
    List of Illustrations
        Page vi
    Introduction
        Page 1
        Page 2
        Page 3
        Page 4
    Geology
        Page 5
        Page 6
        Page 7
        Page 8
    Stratigraphy
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
    Geologic structures
        Page 19
        Page 20
        Page 21
    Ground water
        Page 22
        Page 23
    Mineral resources
        Page 24
        Page 25
    Reference
        Page 26
        Page 27
        Page 28
    Copyright
        Copyright

STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
Tom Gardner, Executive Director




DIVISION OF RESOURCE MANAGEMENT
Jeremy A. Craft, Director




FLORIDA GEOLOGICAL SURVEY
Walter Schmidt, State Geologist



REPORT OF INVESTIGATION NO. 98


GEOLOGY OF SUMTER COUNTY, FLORIDA


By
Kenneth Campbell



Published for the

FLORIDA GEOLOGICAL SURVEY
Tallahassee
1989


UNIIIERSITY OF FLORIDA LIBRARIES








DEPARTMENT
OF
NATURAL RESOURCES


9q9




I SCIENCE
LIBRARY


BOB MARTINEZ
Governor


BOB BUTTERWORTH
Attorney General


GERALD LEWIS
State Comptroller


BETTY CASTOR
Commissioner of Education


DOYLE CONNER
Commissioner of Agriculture


TOM GARDNER
Executive Director


JIM SMITH
Secretary of State


TOM GALLAGHER
State Treasurer


WU~-~--~~-L~ s-'-.7.~r- I ~".7F









LETTER OF TRANSMITTAL


Florida Geological Survey

TALLAHASSEE
August 1989




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

Dear Governor Martinez:

The Florida Geological Survey, Division of Resource Management, Department of Natural Resources,
is publishing as its Report of Investigation No. 98, Geology of Sumter County, Florida. This report, prepared
by Kenneth M. Campbell, P. G. 192, fulfills a need for information on the stratigraphy and hydrogeology
of Sumter County. This information is fundamental to ground-water resource investigations and land use
planning and is of use to other agencies, planners and the citizens of Florida.




Respectfully yours,

Walter Schmidt, Ph.D., P.G.
State Geologist and Chief
Florida Geological Survey












iii
























































Printed for the
Florida Geological Survey

Tallahassee
1989

ISSN 0160-0931



Siv









CONTENTS

Page

Introduction ...... ......................... ............................................................................... 1
Purpose ................................................... ............................................................ 1
Location ............................................................................................................. 1
Clim ate ................................................................................................................ 1
Population..................................................... .................................................... 1
Transportation ......................................... ............................... ......................... 1
M aps................................................................................................................... 1
W ell and Locality Num being System ................................... ................ ........... 1
M etric Conversion Factors ................................................................................. 5
Previous Investigations ......................................................... ............................ 5
M ethods of Investigation .................................................................................. ...... 5

Geology ................. ................................................................................................... 5
Geom orphology .................................................................................................... 5
The M id-Peninsular Zone ........................................................ ...................... 5
Central Highlands......................................................................................... 5
W western Valley ......................... ................................. ........................... 6
Tsala Apopka Plain............................................................................. 6
Brooksville Ridge .......................................................... ......................... 8
Sumter and Lake Uplands .............................................................................. 8
Lake Harris Cross Valley...................... ............................. ..................... 8
Springs ............................................................................................................ 8
Fenney Springs .......................... ...................................... ........................... 8
G um Springs Group ........................................................................................ 8
Other springs ... ...................... ..................... ............................................... 9
Sinkholes ......................................................................................................... 9
Stratigraphy .......................................... ........................................................... 9
Paleozoic Erathem ............................................................................................. 9
M esozoic Erathem ............. .......................... .............................................. 9
Cenozoic Erathem .................... ..................... ............................................ 10
Tertiary System ....................................................... ........ ........................ 10
Paleocene Series ........................................................... ...................... 10
Cedar Keys Form action ...... ................... ........................................... 10
Eocene Series ....................................................................................... 10
O ldsm ar Lim estone............................................. ..... ........................ 10
Avon Park Form ation ............................................................................. 10
Ocala Group................................................................................. ......14
O ligocene Series .................................................................... ........ ..... 16
Suwannee Lim estone ................................. .......... .......................... 16
M iocene Series...................................................................................... 16
Hawthorn G roup Undifferentiated ............................ ............ ............ 16
Pliocene Series................................. ................ ................................... 16
Cypresshead Form ation.......... ................................................ ............. 16
Q uaternary System .................................................................................... 19
Pleistocene and Holocene Series ........................................... ............. 19
Undifferentiated surficial
Sands and clays................................................................................ 19








Geologic Structures.......................................................................................... 19
Peninsular Arch .................................................................................................. 19
Ocala Platform .............................................................................................. 19
Ground Water.................................................................................................... 22
Floridan aquifer system ......................................................... ..................... 22
Intermediate confining unit ...................................................... ................... 22
Surficial aquifer system ......................................................... ..................... 22
Pollution potential ............................................................................................ 24
Mineral Resources .............................................................................................. 24
Limestone ..................................................................................................... 24
P eat....... ............................................................................................ ......... 24
Sand and Clay ............................................................................................... 24

References........................................................................................................... 26


ILLUSTRATIONS
Page
1. Regional Map and cross section locations........................................ ............. 2
2. Index to 7 '/2 minute quadrangle topographic map coverage ............................ 3
3. Well and locality numbering system................................................................... 4
4. Map showing major trans-peninsular physiographic divisions............................ 6
5. Physiographic map of Sumter County and surrounding area............................. 7
6. Structure contour map on the top of the Avon Park Formation......................... 11
7. Geologic cross section A-A'............................................................................... 12
8. Geologic cross section B-B'........................................................ ................... 13
9. Geologic cross section C-C'...................................................... ..................... 13
10. Geologic cross section D-D'................................ .............. ............................ 14
11. Generalized geologic map of Sumter County....................................... ........ 15
12. Structure contour map on the top of the Ocala Group...................................... 17
13. Isopach of Ocala Group. ...................................... ............. ............................ 18
14. Isopach of undifferentiated surficial sand and clay........................................ 20
15. Structure map of peninsular Florida...................................................................... 21
16. Potentiometric surface of upper Floridan aquifer system, September 1985........ 23
17. Ground-water pollution potential.............................. ....................................... 25


TABLE
1. Metric conversion factors....................................................... ........................ 5









GEOLOGY OF SUMTER COUNTY, FLORIDA


by
Kenneth M. Campbell, P. G. 192


INTRODUCTION

PURPOSE
The population growth throughout Florida has
focused attention on the need for comprehensive
development planning. The Florida Legislature in
1985 passed legislation requiring that each county
develop a comprehensive land use plan. The pur-
pose of this report is to provide data on the geology,
hydrology and mineral resources of Sumter County
which will be helpful in making informed planning
and development decisions. In addition, this report
enhances the understanding of the geologic frame-
work of the state.

LOCATION
Sumter County is located in central peninsular
Florida (Figure 1). The county is bounded by Mar-
ion County on the north, Lake County on the east,
Polk County on the south and Citrus, Hernando
and Pasco Counties on the west. The county seat
of Sumter County is Bushnell. The county encom-
passes 561 square miles (Shoemyen et al., 1985),
is approximately 45 miles long in a north-south di-
rection and varies from 6 to 22 miles in width.

CLIMATE
The climate of Sumter County is subtropical, with
warm humid summers and mild, relatively drier win-
ters. Mean monthly temperatures for the period of
record at Bushnell range from approximately 59F
(January) to 81 F (July, August) (National Climatic
Data Center, 1986). The average rainfall at Bush-
nell is approximately 52 inches, with a distinct wet
season from May to September (Simonds and Ger-
man, 1980).

POPULATION
Sumter County was established January 8, 1858
and was the 29th county in the state (Morris, 1979).
In 1970 the population of Sumter County was
14,800; by 1980 the population had increased to
24,300. The county's population is projected to


reach 30,500 by 1990 and over 35,000 by the year
2000 (Shoemyen et al., 1985). The county is
ranked 41st out of 67 counties in the state based
on population.

TRANSPORTATION
Sumter County is served by several tracks of the
Seaboard Coast Line Railroad. Two limited access
highways traverse the county. 1-75 runs north-
south through the county. The Florida Turnpike be-
gins at 1-75 just south of Wildwood and runs south-
east into Lake County. In addition to the two limited
access highways, the county is served by a net-
work of federal, state and county roads. U. S. High-
way 301 and State Road 471 are the primary north-
south roads. State Roads 44, 48 and 50 are the
primary east-west roads.

MAPS
Sumter County is covered by U. S. Geological
Survey 7 1/2 minute topographic quadrangles
(1:24,000 scale). An index to the published maps
is shown as Figure 2. Additional quadrangle maps
covering Sumter County include the Tarpon
Springs and Orlando Sheets (1:250,000 scale) and
the State of Florida (1:500,000 scale). The General
Highway Map of Sumter County is prepared by and
available from the Florida Department of Trans-
portation. Other maps of interest include the En-
vironmental Geology Series, Orlando Sheet (Scott,
1978) and Tarpon Springs Sheet (Deuerling and
MacGill, 1981) as well as the Mineral Resource
Map of Sumter County (Yon et al., 1988).

WELL AND LOCALITY NUMBERING SYSTEM
The well numbering system used in this study is
that of the Florida Geological Survey well filing sys-
tem. Each well is identified by a "W", a dash, and
a one-to-five digit number unique to that well.
Wells and locations within the county are plotted
according to the township, range, and section rec-
tangular system. The location coordinates as-
signed to each well consist of five parts: the





FLORIDA GEOLOGICAL SURVEY


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Figure 1. Regional map and cross section locations.




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Report of Investigation No. 98


R 20 E R 21 E + R 22 E + R 23 E + R 24 E


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Figure 2. Index to 7 1/2 minute quadrangle topographic map coverage.


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FLORIDA GEOLOGICAL SURVEY


RANGE(EAST)
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Figure 3. Well and locality numbering system.


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6 5 4 3 2 11

7 8 9 10 11 12

18 17 16 15 14 13

19 20 21 22 23 24

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Report of Investigation No. 98


township number, the range number, the section
number, and two letters representing the quarter/
quarter location within the section. The basic unit
of this coordinate system is the township, which is
six miles square (Figure 3). Townships are num-
bered consecutively in tiers both north and south
of the Florida Base Line, an east-west survey line
passing through Tallahassee. The township rec-
tangle is also numbered both east and west of the
Principal Meridian, a north-south survey line also
passing through Tallahassee. Each township
square is equally divided into 36 one-square-mile
pieces called sections. Sections are numbered 1
through 36 as shown in Figure 3. The sections are
in turn divided into four quarters labeled a through
d, and each quarter is further divided into quarters
labeled a through d in a similar fashion. Figure 3
provides an example of a well located according
to this system.

METRIC CONVERSION FACTORS
To prevent duplication of parenthetical conver-
sion of units in the text of reports, the Florida Geo-
logical Survey has adopted the practice of inserting
a tabular listing of conversion factors. For those
readers who may prefer to use metric units rather
than the customary English units, the conversion
factors for terms used in this report are given in
Table 1.


Table 1. Metric conversion factors for terms used
in this report.


MULTIPLY

acres
acres
feet
inches
inches
miles
sq. miles
gallons


BY


0.4047
4047.0
0.3048
2.540
0.0254
1.609
2.590
3.7854


TO OBTAIN

hectares
sq. meters
meters
centimeters
meters
kilometers
sq. kilometers
liters


PREVIOUS INVESTIGATIONS
Several publications have discussed the geology
of the Sumter County vicinity in the context of a
regional or statewide report. Cooke (1945) was the
first to specifically present information on the ge-
ology of Sumter County, although this report was


of statewide extent also. Vernon (1951) presented
regional cross sections which included portions of
Sumter County. Puri and Vernon (1964) presented
a geologic map of the entire state as well as phy-
siographic maps of the peninsula of Florida. Chen
(1965) presented a summary of the Paleocene and
Eocene rocks of Florida. Only one of his data
points, however, was located in Sumter County.
Several publications have presented the hydrol-
ogy of portions of Sumter County. Pride et al.
(1961; 1966) discussed the hydrology and general
geology of Green Swamp (includes portions of
southern Sumter County). Rutledge and Grubb
(1978) presented maps of the Green Swamp Area
for several geologic and hydrologic parameters.
Additional authors who have concentrated on the
hydrology of the Sumter County area include Si-
monds and German (1980), Anderson (1980) and
Anderson and Laughlin (1982).

METHODS OF INVESTIGATION
The principal data sources for this study consist
of continuous core and well cutting samples, aug-
mented by field examination of outcrops exposed
in roadcuts, sinkholes, stream beds, and aban-
donded as well as active quarries. Continuous core
samples and well cuttings from over 80 wells in
Sumter County and adjacent portions of surround-
ing counties were examined. These samples are
permanently stored at the Florida Geological Sur-
vey well sample repository in Tallahassee.

GEOLOGY

GEOMORPHOLOGY

The Mid-Peninsular Zone
The Florida peninsula is divided into three phy-
siographic zones (White, 1970). Sumter County is
located within the Central or Mid-Peninsular Zone
(Figure 4) which extends from a line which extends
approximately from St. Johns County to Dixie
County southward to the vicinity of a line drawn
between St. Lucie and Martin Counties on the east
coast and Lee County on the west coast.

Central Highlands
The Central Highlands of the Mid-Peninsular
Zone are bounded to the west by the Gulf Coastal
Lowlands and to the east by the Eastern Valley.






FLORIDA GEOLOGICAL SURVEY


b


Figure 4. Map showing major trans-peninsular physiographic divisions (after White, 1970).


The region is characterized by White (1970) as
"discontinuous highlands in the form of sub-parallel
ridges separated by broad valleys." White (1970)
further states that the ridges are generally above
the potentiometric surface (the level to which water
will rise in a tightly cased well which penetrates the
Floridan aquifer system), while the valley floors are
generally below the potentiometric surface. Broad
shallow lakes are common on the valley floors;
lakes present on the ridges tend to be smaller and
deeper (White, 1970). The ridges are thought to be
remnants of a previous regional upland and the
valleys and uplands of lesser elevation have been
lowered by dissolution (White, 1970).
The geomorphic features which are present in
Sumter County include the Lake and Sumter Up-
lands, the Lake Harris Cross Valley, the Western
Valley, the Tsala Apopka Plain and the Brooksville
Ridge. The majority of Sumter County lies within
the Western Valley and the Tsala Apopka Plain
(Figure 5).


Western Valley
The Western Valley is a large north-south trend-
ing, irregularly shaped low area which is bounded
on the west by the Brooksville Ridge and on the
east by the Sumter and Lake Uplands. The West-
ern Valley is connected to the Central Valley (in
Lake County) by the Lake Harris Cross Valley. The
Lake Harris Cross Valley is an east-west trending
gap separating the Sumter and Lake Uplands. El-
evations within the Western Valley range from ap-
proximately 40 to 100 feet above mean sea level
(MSL).

Tsala Apopka Plain
The boundaries of the Tsala Apopka Plain are
the Brooksville Ridge on the west and the With-
lacoochee River Valley and Lake Panasoffkee on
the east. The plain forms the lowest and flattest
portion of the Western Valley (White, 1970). Tsala
Apopka Lake, in Citrus County, occupies the north-














N


SCALE




EXPLANATION

M CENTRAL
HIGHLANI


Figure 5. Physiographic map of Sumter County and surrounding area (after White, 1970).


| I __






FLORIDA GEOLOGICAL SURVEY


ern portion of the plain. Elevations range from ap-
proximately 40 feet (Tsala Apopka Lake) to about
75 feet above MSL. Tsala Apopka Lake is thought
to be a relict of a much larger lake which occupied
most of the Tsala Apopka Plain (White, 1970).

Brooksville Ridge
The Brooksville Ridge forms the western bound-
ary of the Western Valley. The ridge is present only
in a small portion of west central Sumter County
in the vicinity of Nobleton. The Brooksville Ridge
trends approximately north-northwest to south-
southeast and ranges in elevation from 70 to 200
feet above MSL. The southern part of the ridge
runs through central Citrus, Hernando, and Pasco
Counties, to the west of Sumter County. The
Brooksville Ridge is composed of a core of lime-
stone which is overlain by clayey sands, sandy
clays and clays which are in turn overlain by Pleis-
tocene sands (White, 1970). The clays and clayey
sediments have limited downward percolation of
groundwater, thus limiting the amount of dissolu-
tion of the limestone core of the ridge. The result
is that the Brooksville Ridge stands high relative to
the Western Valley and the Tsala Apopka Plain
(White, 1970).

Sumter and Lake Uplands
The Sumter and Lake Uplands occupy the north-
eastern corner and part of the eastern boundary of
Sumter County. The two uplands are separated by
the Lake Harris Cross Valley. In general, the ele-
vation of the two uplands decreases in a northerly
direction. Elevations within Sumter County range
from 50 to 100 feet above MSL in the northern part
and approximately 75 to 140 feet above MSL in
the southern part.

Lake Harris Cross Valley
The Lake Harris Cross Valley is an east-west
trending valley 8 to 10-miles long and 3 to 5-miles
wide which connects the Western Valley to the
Central Valley. The cross valley separates the Lake
Upland (south of the valley) from the Sumter Up-
land (north). The cross valley is largely occupied
by a series of lakes and associated swamps with
Lake Okahumpka at its western end and Lake Har-
ris in Lake County at the east.


Springs
Springs are limited to the northwest portion of
Sumter County. The springs discharge within the
Lake Panasoffkee drainage basin or to the With-
lacoochee River.

Fenney Springs
Fenney Springs is privately owned and is located
approximately 2 miles east of Coleman (sec.
31bdb, T19S, R23E) and constitutes the head-
waters of Shady Brook which flows through Warm
Springs Hammock into Lake Panasoffkee. The
spring pool is approximately 50 feet in diameter
with banks composed of clay and clayey sand (Ro-
senau et al., 1977). A limestone ledge extends 5
to 10 feet out from the pool edge one to two feet
below the water level. Beyond the ledge the pool
is approximately 25-feet deep (Rosenau et al.,
1977). Discharge is from beneath the limestone
ledge. Outflow from the spring is through a shallow
run with limestone exposed in the bottom near the
spring (Rosenau et al., 1977).
Discharge has been measured on four occa-
sions; minimum flow was 3 million gallons a day
(mgd) while the maximum was 61.7 mgd. Water
color is variable but generally is tannin stained (Ro-
senau et al., 1977).

Gum Springs Group
The Gum Springs Group is privately owned and
is located in the extreme northwest corner of Sum-
ter County (sec. 5cba, T18S, R21E) just to the
south of the Sumter-Marion county line. The Gum
Springs Group reportedly consists of seven indi-
vidual springs (Rosenau et al., 1977) distributed
from the head of Gum Slough to approximately
0.75 mile down stream. The first three springs form
individual pools aligned in a northeast-southwest
direction and flow through separate runs, converg-
ing to form Gum Slough. The remainder of the
springs are located in the channel of Gum Slough
(Rosenau et al., 1977).
The spring pools are 2 to 6-feet deep except for
the vents which are 10 to 20-feet deep. The spring
pools for the uppermost three springs range from
40 to 80 feet in diameter (Rosenau et al., 1977).
Flow is from beneath rock ledges, the tops of which
range from 2 to 10-feet below the spring pools'
surfaces.







Report of Investigation No. 98


Discharge from the spring group has been meas-
ured on two occasions; in 1932, 7.2 mgd and in
1972, 55.5 mgd. Water from the springs was re-
ported to be clear (Rosenau et al., 1977).

Other Springs
Several springs contribute to the flow of Shady
Brook, however, Fenney Springs, discussed
earlier, is the major contributor. Ferguson et al.
(1947) state that Warm Springs and Matahouka
Spring contribute to the base flow of Shady Brook
upstream of the Highway 301 bridge, but do not
provide any additional information. The U.S.G.S.
Wildwood (1967) topographic quadrangle shows
two unnamed springs in this area, as well as three
unnamed springs downstream of the U.S. Highway
301 bridge. Discharge measurements of Shady
Brook at the U. S. Highway 301 bridge average 28
mgd with a minimum of 5.5 mgd and a maximum
of 81 mgd (Rosenau et al., 1977). Two unnamed
springs form the head waters of Little Jones Creek,
which flows into the northeast corner of Lake
Panasoffkee. Rosenau et al., (1977) mention these
springs but do not provide any additional
information.

Sinkholes
Sinclair and Stewart (1985) characterized the
majority of Sumter County as "bare or thinly cov-
ered limestone" in which sinkholes are "few, gen-
erally broad and shallow and develop gradually."
Dissolution sinkholes predominate in this area.
Dissolution sinkholes are formed where the lime-
stone is exposed at the ground surface or where
overlying materials are permeable (Sinclair and
Stewart, 1985). The dissolution process is most
active at the limestone surface and along fractures
and other preferred ground-water flow paths. The
result is a gradual lowering of the limestone surface
and subsidence of the overlying materials. This
type of sinkhole development results in shallow
bowl-shaped depressions and a general rolling to-
pography (Sinclair and Stewart, 1985).
Examination of the topographic quadrangles
shows numerous areas with shallow closed
depressions. In general, identifiable sinkholes are
least common within the Tsala Apopka Plain, the
Western Valley south of Bushnell, and the adjacent
marshy/swampy regions of the Lake Upland. The
most abundant sinkholes are located in the north-
central portion of the county in the Sumter Upland


west of Oxford and Wildwood and north of Cole-
man. Sinkhole frequency decreases somewhat
south of Coleman and to the east in the vicinity of
the Lake Harris Cross Valley. Along the Sumter-
Lake county line in the northern one-third of the
county, sinkhole frequency decreases but the av-
erage depth of those sinks present increases. This
is in response to the presence of the clayey sand
overlying the limestone surface.
Examination of lithologic samples from over 80
water wells and test cores in Sumter County re-
veals the presence of numerous "paleokarst" fea-
tures. These sinkholes are revealed by
examination of the lithologic samples but are not
revealed on the surface by topographic relief. Pa-
leokarst features are most common in the vicinity
of the Lake Harris Cross Valley.

STRATIGRAPHY

Paleozoic Erathem
To date no wells in Sumter County have pene-
trated Paleozoic rocks. Arthur (1988) postulates
that basement rock in Sumter County consists of
Late Precambrian to Early Cambrian intrusive and
extrusive felsic rocks. In the northern portion of the
county, these rocks may be unconformably over-
lain by Paleozoic sedimentary rocks. Paleozoic
rocks are encountered in adjacent counties at
depths which range from 3,405 feet below MSL in
Marion County (W-901, sec. 25aa, T13S, R20E) to
7,685 feet below MSL in Hernando County (W-994,
sec. 19dd, T23S, R18E) (Applin, 1951).

Mesozoic Erathem
Only one well in Sumter County has penetrated
Mesozoic age sediments (W-3, sec. 24ac, T20S,
R22E). An unpublished lithologic log on file at the
Florida Geological Survey by Chen shows the in-
terval from 2,893 to the well total depth at 3,023
feet below MSL as Upper Cretaceous Lawson For-
mation. The lithology reported for this interval was
very finely crystalline, brown dolomite.
Wells in adjacent counties have encountered the
Lawson Formation at depth intervals which range
from 2,374-2,724 feet below MSL (W-18, Marion
Co., sec. 10ad, T16S, R20E) to 3,286-3,766 feet
below MSL (W-275, Lake County, sec. 17dd, T24S,
R25E) (unpublished lithologic logs, Chen). In ad-
dition, these wells penetrated into the "beds of Tay-






FLORIDA GEOLOGICAL SURVEY


lor age" (probably the Pine Key Formation) which
underlies the Lawson Formation (Braunstein et al.,
1988).
Cenozoic Erathem
Tertiary System
Paleocene Series
Cedar Keys Formation
The Cedar Keys Formation is present throughout
the Florida peninsula and is currently considered
to have been deposited during the Late Paleocene
to Early Eocene (Braunstein et al., 1988). The Ce-
dar Keys Formation has been penetrated by only
one well in Sumter County (W-3; sec. 24ac, T20S,
R22E; interval 2,063-2,893 feet below MSL (un-
published lithologic log, Chen). Lithologically, the
Cedar Keys Formation in W-3 consists of greyish-
brown to dark brown, microcrystalline to very finely
crystalline dolostone with variable quantities of
pore filling gypsum (up to 30 percent). Interbedded
with the dolostone are anhydrite beds. It is variably
fossiliferous and contains minor quantities of car-
bonaceous material and ooliths (unpublished lith-
ologic log, Chen).
The top of the Cedar Keys Formation in the vi-
cinity of Sumter County ranges from approximately
1,800 to 2,200 feet below MSL, dipping to the
south-southwest (Chen, 1965). Thickness of the
formation, in the Sumter County area, ranges from
approximately 700 to 1,000 feet, thickening to the
south (Chen, 1965).
The Cedar Keys Formation rests unconformably
on the Upper Cretaceous Lawson Formation
(Chen, 1965; Braunstein et al., 1988). According
to Chen (1965) the formation is conformably ov-
erlain by the Lower Eocene Oldsmar Limestone;
however, Braunstein et al., (1988) indicate that the
contact may be unconformable.

Eocene Series
Oldsmar Limestone
The Oldsmar Limestone is currently considered
to have been deposited during the Early Eocene
to early Middle Eocene (Braunstein et al., 1988).
Chen (1965) described the Oldsmar as "composed
essentially of dolomite and limestone with evapor-
ites (gypsum and anhydrite) as a minor compo-
nent." The limestone characteristically is light
brown to chalky white, fossiliferous, porous and
pure. The limestone is interbedded with brown to
dark brown dolomite which generally is finely to
coarsely crystalline and porous. Evaporites are


rare as discrete beds and are much less abundant
than in the underlying Cedar Keys Formation
(Chen, 1965).
The Oldsmar Limestone is penetrated by two
wells in Sumter County: W-3; sec. 24ac, T20S,
R22E; 1,353-2,063 feet below MSL, (unpublished
lithologic log, Chen, 1963) and W-250; sec. 36b,
T20S, R22E; 1,361 to well total depth of 1,886 feet
below MSL (unpublished lithologic log, Caldwell).
The Oldsmar in Sumter County is composed pri-
marily of dolostone and limestone, white to gray
and brown, microcrystalline to medium crystalline,
variably fossiliferous, variably porous, with minor
chert, crystalline quartz and gypsum (unpublished
lithologic logs by Chen; Caldwell).
The top of the Oldsmar Limestone in Sumter
County ranges from approximately 1,000 to 1,500
feet below MSL and dips to the southwest (Chen,
1965). The thickness of the formation ranges from
approximately 600 to 800 feet in the county. The
Oldsmar Limestone is conformably overlain by the
Avon Park Formation and unconformably overlies
the Cedar Keys Formation (Braunstein et al.,
1988).
Avon Park Formation
The Middle Eocene Avon Park Formation is the
oldest exposed formation in Florida. The Avon Park
is present in the subsurface throughout Sumter
County, but is not exposed within the county. The
Avon Park Formation usage in this report reflects
the nomenclatural changes set forth by Miller
(1986). Miller combined the Avon Park Limestone
and Lake City Limestone of prior usage into the
Avon Park Formation. These changes were made
because: 1) there are no consistent lithologic cri-
teria on which to differentiate the two units and 2)
considerable quantities of dolomite are present.
Within Sumter County, the Avon Park Formation
may be either limestone or dolostone. Generally
the uppermost 30 to 70 feet of the formation con-
sists of limestone, underlain predominantly by do-
lostone or dolomitic limestone. The limestone of
the Avon Park typically is white, cream or brown
in color, poorly to well indurated, wackestone to
very fine grained packstone. The limestone may
be thin bedded to relatively structureless and com-
monly contains organic material as flecks and thin
seams. Where the formation is dolomitized it con-
sists of microcrystalline to fine grained, unconso-
lidated to well indurated, euhedral to subhedral
dolomite crystals.








Report of Investigation No. 98


R 20 E R 21 E + R 22 E + R 23 E +


Explanation

* Well location

Contour interval 20 Ft.
All depths relative to
Mean Sea Level.


R 20 E R 21 E R 22 E R 23 E +
,


Figure 6. Structure contour map on the top of the Avon Park Formation.


R 24 E


CO)

-4-


I-'

C-,
0
-t




-4-

.--q
H
C-,
ro
o


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R 24 E
























ii -a
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Figure 7. Geologic cross section A-A' (See Figure 1 for section location).


., I


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Cl CD
SVIIE


U

6


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S ____
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Sw-ts iS-li-s


w-LaiTMs aONIT
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- I f LASS COUMTT
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FLORIDA GEOLOGICAL SURVEY


j 4




1e


us 4 0


Figure 10. Geologic cross section D-D' (See Figure 1 for section location).


The top of the Avon Park Formation in Sumter
County ranges from approximately 15 feet above
MSL to approximately 80 feet below MSL (Figures
6-10). The thickness of the Avon Park within Sum-
ter County ranges from approximately 1,100
to1,400 feet, thickening generally to the south and
south-southwest (Chen, 1965). The Avon Park is
conformably underlain by the Oldsmar Limestone
and unconformably overlain by the Ocala Group
(Braunstein et al., 1988).

Ocala Group
All of Sumter County is underlain by limestone
of the Upper Eocene Ocala Group (Figures 6-10).
The Ocala Group consists of three formations,
which in ascending order are, the Inglis, Williston
and Crystal River Formations (Purl, 1957). The In-
glis Formation cannot be recognized in Sumter
County based solely on lithologic characteristics;
however, limestone containing fossils found in the
Inglis Formation is present. These sediments are
included in the Williston Formation.


The Williston Formation in Sumter County is a
white to cream or tan colored, poorly to well in-
durated, fine to medium grained, grainstone to
packstone composed in large part of miliolid fora-
minifera. Cement may be either calcilutite or sparry
calcite. The most common fossils include miliolid
and other foraminifera, mollusks and echinoids.
Limestone of the Williston Formation forms the
bedrock in the Tsala Apopka Plain area of northern
and western Sumter County (Figures 8 and 11).
The Williston unconformably overlies the Middle
Eocene Avon Park Formation and conformably un-
derlies the Crystal River Formation where that for-
mation has not been removed by erosion. The
boundary between the Crystal River and the Wil-
liston is transitional. Where the Crystal River For-
mation has been removed by erosion, the Williston
Formation is unconformably overlain by Miocene
to Holocene siliciclastic sediments.
The Crystal River Formation in Sumter County
is a white to very pale orange, poorly to moderately
indurated, variably recrystallized, fine to medium
grained packstone to wackestone. The Crystal


D
D o
0^


*imic i ,nI4 MiiS






Report of Investigation No. 98


0 4 M
0 3 6 K


t R 21 E T R 22 E R 23 E R 24 E
-4
-x 1 -------------- o
x Tcr I |-
S ,u ** I
rw Qu Qu
\ *


\ Tw /Tcy
\\ /.T
iles I *,
ilometers x \\x




Tw \ V
Q-4

/\ Qu

I-I
L -4? ^ ^ --- -A --------------





T / /,
L R)





Lanation Tcr
location
.op u
y or Mine Pit
Fferentiated surficial Qu *\
Sand clay **
resshead Formation
stall River Formation Tcr.
S cr -c
Iston Formation
Ln



SR 21 E R 22 E R 23 E R 24 E


Figure 11. Generalized geologic map of Sumter County.


Expl
Vell I
Outcr
Quarr
Undi
sane
Cyp
Cry
WVitll


R 20 E





FLORIDA GEOLOGICAL SURVEY


River Formation is abundantly fossiliferous, com-
monly forming a coquina of large foraminifera. The
most common fossil types include foraminifera
(large and small), echinoids, mollusks and bryozoa.
The Crystal River Formation is conformably and
gradationally underlain by the Williston Formation.
In Sumter County, the Crystal River Formation is
unconformably overlain by Miocene to Holocene
siliciclastic sediments. The Crystal River forms the
bedrock in Sumter County wherever it is present.
In Sumter County, the boundary between the
Crystal River Formation and the Williston Forma-
tion is often difficult to delineate. This is due to two
primary factors: the lithologically gradational nature
of the contact and extensive recrystallization. Be-
cause of the difficulty in reliably picking the top of
the Williston Formation, isopach and structure
maps were prepared only for the undifferentiated
Ocala Group (Figures 12 and 13.)
The elevation of the top of the Ocala Group in
Sumter County ranges from approximately sea
level to a maximum of approximately 95 feet above
MSL (Figure 12). The highest elevations exist along
the Marion-Sumter county line to the north of Wild-
wood, in the vicinity of the towns of Sumterville and
Center Hill and the area south of State Highway
50. The top of the Ocala Group throughout the
majority of the county is between 20 and 60 feet
above MSL.
The thickness of the Ocala Group within Sumter
County ranges from less than 20 feet along the
Withlacoochee River in the northwest portion of the
county to more than 120 feet in the area south and
east of Wildwood and the area south of St.
Catherine, Webster and Center Hill (Figure 13).
The elevation of the top of the Ocala Group as well
as its thickness is very irregular within the Lake
Harris Cross Valley due to extensive paleokarst
development.

Oligocene Series
Suwannee Limestone
The Oligocene age Suwannee Limestone which
overlies the Ocala Group throughout much of pen-
insular Florida is not, in general, present in Sumter
County, having been removed by erosion. Rem-
nant boulders of silicified Suwannee Limestone are
common throughout the central and southern parts
of the county. Thin, small, isolated pockets of Su-
wanneo Limestone, although not observed in wells


examined for this study, may be preserved in low
spots on the top of the Crystal River Formation.
Yon and Hendry (1972) described the Suwannee
Limestone in Hernando and Pasco Counties as
variably recrystallized, very pale orange limestone
(primarily packstone), poorly to well indurated with
sparry calcite, slightly quartz sandy (very fine), silty
and clayey, generally very microfossiliferous and
having variable moldic porosity. In quarry sections,
the hard packstone is often interbedded with soft
wackestone beds.
Miocene Series
Hawthorn Group Undifferentiated
Sediments of the Miocene age Hawthorn Group
undifferentiated (Scott, 1988a) were encountered
in 10 wells within Sumter County. Eight of these
wells are located in the northeast corner of the
county, within the Sumter Upland. The present au-
thor considers these occurrences to be isolated
remnants of Hawthorn or reworked Hawthorn sed-
iments, not a mappable unit. The erosional edge
of the Hawthorn Group is shown by Scott (1988a)
to lie approximately along the Sumter-Lake county
line. The Hawthorn is, in general, present through-
out Lake County to the east, thickening and dipping
to the south-southeast. Previous authors have as-
signed these materials to either the Hawthorn or
Alachua Formations (Cooke, 1945; Vernon, 1951).
Lithologically, the Hawthorn Group sediments
encountered in Sumter County consist of clayey,
phosphatic sands and sandy, phosphatic clay. El-
evation of the top of these occurrences of Hawthorn
Group sediments range from 18 to 73 feet above
MSL. Thickness of the Hawthorn sediments ranges
from 5 to 35 feet (Figures 7, 8).

Pliocene Series
Cypresshead Formation
The Cypresshead Formation is a new forma-
tional name established in the coastal plain area
of Georgia (Huddlestun, 1988). In peninsular Flor-
ida, these sediments have been correlated with the
Citronelle Formation (Cooke and Mossom, 1929)
and have been called Citronelle Formation (Cooke,
1945; Pirkle et al., 1963, 1965). In order to clarify
the nomenclatural situation, the Cypresshead For-
mation is adopted for these sediments in Florida
(Scott, 1988b). There are several reasons that this
appears appropriate: 1) these sediments are trace-







Report of Investigation No. 98


R 20 E + R21 E + R 22 E + R 23 E i R 24 E


Explanation

Well location
Outcrop
Quarry or Mine Pit
Contour interval 20 Ft,
All elevations relative
to Mean Sea Level


R 20 E R 21 E R 22 E


R 23 E


Figure 12. Structure contour map


--I
i-a
OD
00

-4-

-I

"D
I-






-I


-H-

ro

--I
.-4














R)
R)

-4-
-4





(A




-I-
-4





--

-I
U(
')


R 24 E


on the top of the Ocala Group.





FLORIDA GEOLOGICAL SURVEY


R 20 E + R 21 E + R 22 E + R 23 E +


R 24 E


N
N


0 4 Miles
0 3 6 Kilom


* Well loca
Contour
All elevatic
Mean Sea L


R 20 E


80 120
1200



-1
action fl
tlon
interval 20 Ft.,
>ns relative to
evel
4ro
-4



,n



21 E R 22 E R 23 E R 24 E


Figure 13. Isopach of Ocala Group.






Report of Investigation No. 98


able from Georgia into Florida, 2) the Citronelle
Formation in the panhandle of Florida is widely
separated from the occurrences of Cypresshead
Formation in peninsular Florida, 3) the Miccosukee
Formation lies laterally between the Citronelle and
the Cypresshead and is laterally equivalent to both
and 4) the Citronelle Formation is chiefly non-ma-
rine (Matson, 1916) whereas the Cypresshead For-
mation is chiefly marine (Huddlestun, 1988).
The Cypresshead Formation in Sumter County
consists primarily of fine to coarse, variably gravelly
quartz sand and clayey sand with small quantities
of mica. Bedding style ranges from massive in ap-
pearance to conspicuously crossbedded.
Crossbedded zones appear to be coarser than
other beds and are associated with larger quan-
tities of quartz and quartzite gravel. Burrows are
common.
Due to weathering, there is a distinct zonation in
most pits and exposures of the Cypresshead
Formation (Pirkle et al., 1963). The upper zone
consists of red and yellowish-orange, massive
appearing material. Underlying the upper zone is
a red to yellowish-orange transitional unit. The
lowermost zone is a predominantly white, clayey
sand. Pirkle et al. (1963) report that the weathering
bands mimic the present day topography and that
there is evidence to suggest that, during post-
depositional weathering, clay has migrated
downward into the upper zone from the overlying
sediments, leaving a blanket of uncemented sand
at the land surface.
The Cypresshead Formation is found only along
the eastern edge of Sumter County (Figures 7-11)
but is present throughout the majority of Lake
County and the eastern one-third of Marion County.
Elevations of the top of the Cypresshead in Sumter
County range from approximately 50 to 95 feet
above MSL. Thickness of the formation in Sumter
County is typically in the range of 10 to 40 feet.
Quaternary System
Pleistocene and Holocene Series
Undifferentiated Surficial Sand and Clay
The majority of Sumter County is blanketed with
undifferentiated surficial sediments consisting pri-
marily of quartz sand, clayey sand and clay. The
thickness of these sediments ranges, in general,
from just a few feet to approximately 40 feet (Fig-
ures 7-10, 14). Within filled sinkholes undifferen-
tiated sediments can be well in excess of 100 feet
thick.


The general lithology of the undifferentiated sur-
ficial sediments is variable, including fine to coarse
grained sand, clayey sand, sandy clay and clay.
Clay content generally increases downward, as
does the occurrence of limestone and phosphatic
limestone fragments. Peat or organic rich sedi-
ments are found at the surface in some parts of
the county.

GEOLOGIC STRUCTURES
The primary structural features which affect the
geology of Sumter County are the Paieozoic age
Peninsular Arch and the Tertiary age Ocala Plat-
form (Figure 15). Sumter County is located over
the western flank of the Peninsular Arch. The Ocala
Platform underlies essentially all of Sumter County.
Peninsular Arch
The Peninsular Arch was named by Applin
(1951) for an "anticlinal fold, or arch which is ap-
proximately 275-miles long, trends south-south-
eastward and forms the axis of the Florida
peninsula as far south as the latitude of Lake Okee-
chobee." Applin further stated that the Peninsular
Arch is the dominant subsurface structural feature
in the Florida peninsula. Applin (1951) showed the
Peninsular Arch as a topographic high during Cre-
taceous time with Lower Cretaceous sediments
pinching out against it, with Upper Cretaceous sed-
iments deposited over the crest of the arch.

Ocala Platform
The Ocala Platform was originally named the
Ocala Uplift in a 1920 U.S.G.S. press release by
Mr. O. B. Hopkins. Vernon (1951) formally de-
scribed the feature as "developed in Tertiary sed-
iments as a gentle flexure, approximately 230-
miles wide where exposed in central peninsular
Florida." Vernon additionally believed that the crest
of the uplift had been flattened by "vertical dip-slip
faults," the traces of which parallel the crest of the
uplift. Vernon (1951) dated formation of the feature
as Early Miocene. Cooke (1945) suggested that
the development began prior to the Late Eocene.
Applin (1951) cautioned that the Peninsular Arch
was a separate feature from the Ocala Uplift and
suggested that the name Ocala Uplift be restricted
to the Tertiary feature. Vernon (1951) stated that
well data shows that the two features are not su-
perimposed and that wells drilled on the crest of
the Ocala Uplift penetrate the western flank of the






FLORIDA GEOLOGICAL SURVEY


R 20 E + R 21 E + R 22 E t-R 23 E +


V) I




-220
SD \\




0 4 Miles -1\o \ ) ,eo

0 3 6 Kilometers x) (0




CU 20


.4-

2 0 x


20 40
10 20 30
0

cu /
F-
30


m) Explanation

NU Well location
x Outcrop
w Quarry or Mine Pit
0 Contour interval 10 FT.
All elevations relative to
Mean Sea Level


R 20 E R 21 E R 22 E R 23 E


Figure 14. Isopach of undifferentiated surficial sand and clay.


R 24 E


--

co


()

-a




ro
-0-


nO
o
CU





nO
-a
-I







po
cu
.-i






0*


R 24 E






Report of Investigation No. 98


ALABAMA


GEORGIA


SOUTHEAST
J GEORGIA
EMBAYMENT


JACKSONVILLE
BASIN


(C -


ST. JOHNS
PLATFORM


SANFORD


EMBAYMENT

0,
OxC


O
\0
0


FLORI


OKEECHOBEE
BASIN \


0 50 100 150 MILES
I --I ---I
0 80 160 240 KILOMETERS
SCALE


Figure 15. Structure map of peninsular Florida (modified from Scott, 1988a).


I
I


I

I

J31.





FLORIDA GEOLOGICAL SURVEY


Peninsular Arch. Scott (1988a) suggested the term
Ocala Platform as preferable to uplift, as deposi-
tional and erosional processes may have played a
major role in the development of the feature and
since the term platform does not have a structural
connotation.

GROUND WATER

Floridan aquifer system
The Floridan aquifer system in Sumter County
is comprised of rocks of the Eocene age Ocala
Group and Avon Park Formation and is the primary
source of potable water within the county. Moore
et al., (1986) consider the Floridan aquifer system
to be unconfined throughout the majority of Sumter
County. Anderson and Laughlin (1982) portray es-
sentially all of the county as areas of either high
recharge (little or no surface runoff) or moderate
recharge (moderate surface runoff). The only area
of Sumter County in which significant surface runoff
occurs is the Green Swamp in the southern part of
the county. Despite the presence of surface runoff,
Pride et al. (1966) stated that the Green Swamp
area is a recharge area to the Floridan. The re-
charge potential of the Tsala Apopka Plain is lim-
ited because the potentiometric surface (the level
to which water will rise in a tightly cased well which
penetrates the aquifer) is at or near the land surface
(Anderson and Laughlin, 1982).
The potentiometric surface of the upper Floridan
aquifer system in Sumter County is highest in the
Green Swamp area at 90-100 feet above MSL, and
lowest in the Withlacoochee River Valley north of
the Outlet River (from Lake Panasoffkee) at ap-
proximately 40 feet above MSL (Barr, 1985) (Figure
16). The regional dip of the potentiometric surface
is to the northwest. Pumping associated with lime-
stone mining in the areas of Center Hill and Sum-
terville causes local lowering of the potentiometric
surface (Barr, 1985).
The top of the Floridan aquifer system is less
than 50 feet below the land surface for the majority
of the county (Figures 12 and 14). Well data indi-
cate that the limestone surface in a small area in
the east-central part of the county, including and
adjacent to the west end of the Lake Harris Cross
Valley is very irregular and that depth to the top of
the Floridan ranges from approximately 10 to 160
feet below the land surface, and averages 60 to 70
feet.


Pride et al. (1966) characterized the water quality
of the Floridan aquifer system in the Green Swamp
area as good, with dissolved solids in the range of
100 to 400 mg/L (milligrams per liter) with approx-
imately 75 percent attributed to calcium carbonate
(hardness). Data from 27 wells in Sumter County
(Anderson and Laughlin, 1982) show a range of
139 to 1,130 mg/L for total dissolved solids. Hard-
ness ranged from 87 to 820 mg/L with an average
of 230 mg/L. Iron content within the Green Swamp
was in general greater than 0.3 mg/L and exceeded
that figure in one-half of the wells tested by An-
derson and laughlin (1982). Sulfides exceeded
0.05 mg/L in each of the 10 Sumter County wells
tested, while sulfates exceeded 250 mg/L in two
wells (Anderson and Laughlin, 1982).

Intermediate confining unit
Confining beds are absent or inefficient through-
out much of the county. Where present, confining
beds are composed of clay and clayey sand. Con-
fining beds are best developed along the eastern
edge of the county and within the Green Swamp
area of southern Sumter County.

Surficial aquifer system
The surficial aquifer system in Sumter County is
comprised primarily of undifferentiated surficial
sands and clayey sands as well as the clayey
sands of the Cypresshead Formation. The surficial
aquifer system is absent, or nearly so within the
Green Swamp, where limestone is at or near the
land surface and where the potentiometric surface
of the Floridan aquifer system is at or near the land
surface. The surficial aquifer system can be ex-
pected to be best developed where the top of the
Floridan is deepest relative to the land surface, in
general in the vicinity of Webster and in the north-
eastern and east-central part of the county. Thick-
ness of the surficial aquifer system ranges from
zero to approximately 60 feet.
Water quality within the surficial aquifer system
is generally better than that of the underlying Flor-
idan aquifer system, due to the source of the water
(local precipitation) and the insoluble nature of the
aquifer materials. The surficial aquifer system may
provide sufficient water for small volume uses,
however, the Floridan aquifer system is the dom-
inant source due to its reliability.






Report of Investigation No. 98


+ R 23 E


00
'I-
o



N

0 4 Miles
0 3 6 Kilometers










-4

(U
F-I













S Contour interval 10 FT,

All elevations relative to
rA Mean Sea Level


R 20 E R 21 E R 22 E


R 23 E


R 24 E


.--
-I
,,D


-14


ro
,4-


H



.-4
-4-

-I
n)


'o






ro
c^
-4-

-I
mU
'4


R 24 E


Figure 16. Potentiometric surface of upper Florida aquifer system, September 1985 (after Barr, 1985).





FLORIDA GEOLOGICAL SURVEY


Pollution Potential
A standardized system for evaluating ground-
water pollution potential using hydrogeologic set-
tings (DRASTIC) study of Sumter County was con-
ducted by Seaburn and Robertson (1986). The
acronym DRASTIC is derived from the parameters
examined: Depth to water, net Recharge, Aquifer
media, Soil characterisitcs, general Topography,
Impact of the vadose zone, and hydraulic Conduc-
tivity of the aquifer. Results of this survey indicate
that all but a small portion of east-central Sumter
County has moderate to high pollution potential
(Figure 17).

MINERAL RESOURCES

Limestone
Crushed limestone is the major mineral com-
modity produced in Sumter County. The several
companies in operation within the county are min-
ing predominantly from the Upper Eocene Crystal
River Formation. Four companies are currently
mining limestone in Sumter County in the vicinities
of Sumterville, Center Hill, St. Catherine and in
extreme southernmost Sumter County along the
Polk-Sumter county line (Yon et al., 1988).
All limestone mined in the county is mined from
open pit quarries. Generally, overburden must be
removed by bulldozers prior to mining. In some
areas, the limestone is soft enough that bulldozers
equipped with a claw can rip the rock loose. If
harder rock is encountered, drilling and blasting are
necessary to fracture the rock. Where mining ex-
tends below the water table and pits remain
flooded, draglines are utilized in mining. After min-


ing, the material is transported by truck to proc-
essing plants to be crushed and stockpiled. The
primary products are dense road base material and
agricultural lime.

Peat
Two companies are currently mining peat from
Holocene age deposits within Sumter County (S.
Spencer, personal communication, 1988). These
deposits are located east of Oxford near the Lake
County line and near the Withlacoochee River
southwest of Tarrytown.
Mining is accomplished by clearing the surface
of vegetation, pumping to dewater the peat, then
excavating the peat with a dragline. The peat is
then shredded and stockpiled to dry. All of the peat
produced is utilized for various horticultural pur-
poses such as landscaping and potting soils, al-
though some of the peat is suitable for energy
applications (Bond et al., 1986).

Sand and Clay
Quartz sand and clayey sand are present at the
surface throughout virtually all of Sumter County.
Clay occurs sporadically within the undifferentiated
surficial sediments as beds and as matrix material
in sands of the Cypresshead Formation as well as
the undifferentiated surficial sediments. No sand or
clay is currently mined in Sumter County; however,
these materials are locally used as fill material. Yon
et al. (1988) indicated that these sands may be
useful for brick masonry, sand-cement riprap,
sand-asphalt hot mix and sand seal coat. The lim-
ited extent of clay deposits preclude economic uti-
lization of clay in Sumter County.





Report of Investigation No. 98


0 4 MIles
0 3 6 Kilomi


POLLUTION POTENTIAL


HLOW

MEDIUM

HIGH


R 20 E


Figure 17. Ground-water pollution potential (after Seaburn and Robertson, 1986).


R 24 E


R 24 E






FLORIDA GEOLOGICAL SURVEY


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Report of Investigation No. 98


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FLRD GEOLOSk ( IC SUfRiW


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