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Geology and geomorphology of Levy County, Florida ( FGS: Open file report 19 )
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 Material Information
Title: Geology and geomorphology of Levy County, Florida ( FGS: Open file report 19 )
Series Title: ( FGS: Open file report 19 )
Physical Description: 18, 3 p. : ill. ; 28 cm.
Language: English
Creator: Rupert, Frank
Florida Geological Survey
Publisher: Florida Geological Survey
Place of Publication: Tallahassee Fla
Publication Date: <1988>
 Subjects
Subjects / Keywords: Geomorphology -- Florida -- Levy County   ( lcsh )
Geology -- Florida -- Levy County   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by Frank R. Rupert.
Bibliography: Includes bibliographical references.
General Note: Cover title.
General Note: "May, 1988"
Funding: Digitized as a collaborative project with the Florida Geological Survey, Florida Department of Environmental Protection.
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Source Institution: University of Florida
Holding Location: 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 - 001545440
oclc - 21188514
notis - AHF8960
System ID: UF00001018:00001

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Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Page 1
    Geomorphology
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
    Stratigraphy
        Page 8
        Page 9
        Page 10
        Page 11
        Page 7
        Page 12
    Groundwater
        Page 13
        Page 14
        Page 12
    Mineral resources
        Page 15
        Page 14
        Page 16
        Page 17
    References
        Page 18
        Page 17
    Maps and figures
        Page 19
        Page 20
        Page 21
        Copyright
            Main
Full Text










State of Florida
Department of Natural Resources
Tom Gardner, Executive Director




Division of Resource Management
Jeremy Craft, Director




Florida Geological Survey
Walt Schmidt, State Geologist and Chief









Open File Report 19


Geology and Geomorphology of
Levy County, Florida

by

Frank R. Rupert


Florida Geological Survey
Tallahassee, Florida
1988


























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Florida Buread of Geology Library
903 W. Tennessee Street
Tallahassee, Florida 32304



State of Florida
Department of Natural Resources
Tom Gardner, Executive Director



Division of Resource Management
Jeremy Craft, Director



Florida Geological Survey
Walt Schmidt, State Geologist










Open File Report 19

Geology and Geomorphology of Levy County, Florida




by

Frank R. Rupert


Florida Geological Survey
Tallahassee, Florida
May, 1988


. 1





Levy County


GEOMORPHOLOGY

Levy County lies near the northern edge of the Mid-

peninsular Zone of White (1970). This zone spans the Florida

peninsula from the lower edge of the topographically higher

Northern Highlands southward to approximately the Caloosahatchee

River. The Mid-peninsular zone is partitioned into a series of

elevationally-differentiated geomorphic subzones. Two of these
subzones occur within Levy County, the Central Highlands and the

Gulf Coastal Lowlands (White, 1970).

Central Highlands


The Central Highlands geomorphic province includes a series

of localized highlands and ridges punctuated by topographically

lower valleys, all of which trend generally coast-parallel down

the central Florida peninsula. Two geomorphic subdivisions of

the Central Highlands occur in eastern Levy County, the Western

Valley and the Brooksville Ridge.


The Western Valley

The Western Valley geomorphic subzone (White, 1970) borders

the eastern edge of Levy County, and locally includes the

Williston Limestone Plain of Vernon (1951). The terrain is

characteristically a gently-rolling limestone plain covered by a

thin blanket of Pleistocene (1.8 million years to 10,000 years

before present) sands and containing localized pockets of

phosphatic Alachua Formation sediments. Outcrops of the

underlying Eocene (54 to 36 million years before present)





limestones are common. Elevations on the Williston Limestone

Plain in Levy County generally range from 60 to 90 feet above

mean sea level (MSL).

Brooksville Ridge

The Brooksville Ridge is a topographic highland extending

from northeastern Gilchrist County southward through eastern Levy

County, terminating 10 omiles..to the south in Pasco County. In

Levy County, the ridge sediments rest on highly karstic, Eocene

limestone. The core of the ridge is largely comprised of

Pleistocene siliciclastics and is capped by a depression-pocked

rolling plain of Pleistocene marine terrace sands. Surface

elevations range from 60 feet MSL at the western edge of the

Ridge, to approximately 135 feet MSL along portions of the crest.


Gulf Coastal Lowlands

The Gulf Coastal Lowlands geomorphic province parallels the
present Gulf Coast of Florida from Ft. Myers northward, then

westward around the Big Bend to the Alabama line. In the

vicinity of Levy County, the Gulf Coastal Lowlands extend inland

from the modern Gulf of Mexico shoreline distances of between 15

and 30 miles, terminating at the western edge of the Brooksville

Ridge (see Figure i). The Gulf Coastal Lowlands in Levy County

are characterized by broad, flat marine erosional plains,

underlain by Eocene limestones, and blanketed by thin Pleistocene

sands deposited by the regressing Gulf of Mexico. Elevations

within this province vary from 0 feet-MSL at the Gulf shoreline,

to about 60 feet MSL near the Brooksville Ridge. Several

geomorphic subdivisions, based on topography, punctuate the Gulf






Coastal Lowlands zone in Levy County. These include the

Waccasassa Flats, the Limestone Shelf and Hammocks, the Chiefland

Limestone Plain, the Suwannee River Valley Lowlands, and the

Coastal Marsh Belt (Vernon, 1951).

Waccasassa Flats

Vernon (1951) proposed the name Waccasassa Flats for the

low, swampy area averaging about five miles wide and 25 miles

long, trending from the Santa Fe River in Gilchrist County,

southeastward into central Levy County. Land surface elevations

over most of the "Flats" average about 55 feet MSL, although

isolated sand hills, possibly associated with Wicomico marine

terrace deposits and the Brooksville Ridge, reach elevations of

nearly 70 feet MSL. At the southern terminus of the Waccasassa

Flats, the zone broadens to about 14 miles wide, and elevations

decrease to 30 feet MSL as the "Flats" merge into the hammocks of

southwestern Levy County. The Waccasassa River, which originates

as a poorly-defined channel in the swamps, lakes, and tyty ponds

in northern Levy County, drains the lower reaches of the

Waccasassa Flats. It flows southwestward and empties into the

Gulf of Mexico. The upper portion of the Waccasassa River flows

in a poorly-defined channel in sandy alluvium. South of U.S. 98,

the river is incised in a limestone channel. A narrow Holocene

floodplain of muds and sand occurs near the coast, where the

river merges with the coastal swamps.

The origin of the Waccasassa Flats is uncertain. Vernon

(1951) believed that the "Flats" are either a remnant stream

valley, possibly of ancestral Suwannee River, or are of erosional






marine origin. Due to the predominance of relict marine features

throughout the area of the flats, Puri et al. (1967) consider

this feature to be marine in origin.

Limestone Shelf and Hammocks

The Limestone Shelf and Hammocks subzone, as used in this

report, includes the Pamlico Terrace of Vernon (1951). This zone

is characterized by a highly karstic, erosional limestone plain

overlain by sand dunes, ridges, and coast-parallel paleo-

shoreline sand belts associated with the Pleistocene-age Pamlico

marine terrace (approximately 10 to 25 feet MSL). The irregular,

highly solutioned Eocene limestone underlying this area is masked

by a blanket of Pleistocene sands. Near the modern coast, the

limestone shelf is drowned by the coastal marshes. Inland, the

limestone rises gently to an elevation of about 20 feet MSL, and

is heavily forested. Numerous artesian springs flow from the

near-surface limestone, and during periods of heavy rainfall,

much of- the area floods to form a shallow swamp. Drainage from

the coastal hammocks occurs through numerous small creeks and

sloughs, which empty into the coastal marshes.


Chiefland Limestone Plain

The flat, karstic limestone shelf in northwestern Levy

County associated with the Pleistocene-age Wicomico Terrace is

named the Chiefland Limestone Plain (Vernon, 1951). This plain

extends from Gilchrist County southward into Levy County,

terminating against the Limestone Plain and Hammocks zone, and

bounded by the Waccasassa Flats on the east. The terrain is

generally flat to rolling, characterized by a veneer of well-






drained Pleistocene sands, generally less than 30 feet thick,

overlying the solutioned Eocene limestones. Elevations range

from 25 feet MSL at the southern edge of the plain, to nearly 50

feet MSL at the Levy-Gilchrist County line.


Suwannee River Valley Lowlands

The Suwannee River forms the northwestern boundary of Levy

County, and empties into the Gulf of Mexico. This river flows in

a solution valley, formed in the near-surface Eocene limestones.

The lowlands immediately adjacent to the river, floored by a thin

veneer of Holocene alluvium and exposed limestone, comprise..the .....

Suwannee River Valley Lowlands geomorphic subzone (Vernon, 1951).

The broadly-meandering valley is less than one mile wide over

most of its course, broadening to about two and a half miles wide

just northwest of Chiefland; valley floor elevations average

about five feet MSL. Along its lower stretch, the river valley

is drowned and obscured by marshes of the Coastal Marsh Belt

zone.


Coastal Marsh Belt

The Coastal Marsh Belt is situated on the drowned, seaward

edge of the Eocene limestone shelf underlying Levy County.

Elevations are less than five feet MSL. The gentle slope of the

limestone plain results in a very broad shallow continental shelf

off the Florida Big Bend. Sediments are predominantly muds and

alluvial sands. Due to the "zero-energy" nature of the shoreline

and lack of an adequate sand supply, beaches are vitrually absent

(Tanner, 1960). Marshes of Juncus and Spartina grasses fringe






the modern coastline, and a series of small islets or keys,

comprised of limestone pinnacles or alluvial sand, are common

offshore of the modern coast.


STRATIGRAPHY

The oldest rock commonly penetrated by water wells in Levy

County is marine limestone of the Eocene age Avon Park Formation.

Undifferentiated Pleistocene to Holocene age surficial sands,

clayey sands, and alluvium are the youngest sediments present.

The Avon Park Formation and the younger overlying limestone units

are important freshwater aquifers, and this discussion of the

geology of. Levy County is confined to these Eocene. age and

younger sediments.


Eocene Series

Avon Park Formation

The Avon Park Formation (Miller, 1986) is a lithologically

variable Middle Eocene carbonate unit underlying all of Levy

County. It is typically a tan to buff to brown dolomite,

frequently interbedded with white to light cream to yellowish

gray limestones and dolomitic limestones, and containing varying

amounts of peat, lignite, and plant remains (Vernon, 1951, and

Florida Geological Survey in-house lithologic files). Mollusks,

echinoids, and foraminifera, where preserved, are the principal

fossils present. The top of the Avon Park Formation varies in

depth from surface outcrop along the crest of the Ocala Platform,

to nearly 150 feet deep in northern and eastern Levy County.

Surface exposures occur in two large areas, one around and west

of the town of Gulf Hammock, and a second extending from just







south of Lebanon Station southeastward into Citrus County. oil

test wells which have penetrated the entire Avon Park Formation

section under Levy County reveal a total thickness for this unit

of approximately 800 to 1100 feet (Florida Geological Survey in-

house well files).

Ocala Group

Marine limestone ofi the Ocala Group (Puri, 1957)

unconformibly overlie the Avon Park Formation under all of Levy

County except along the crest of the Ocala Platform, where the

younger limestone erosionally pinchout against the Avon Park

Formation (Vernon, 1951). The Ocala Group is comprised of three

Formations; in ascending order, they are the Inglis Formation,

the Williston Formation, and the Crystal River Formation. These

formations are differentiated on the basis of lithology and

fossil content. Typically, the lithology of the Ocala Group

grades upward from alternating hard and soft, white to tan to

gray fossiliferous limestone and dolomitic limestone of the

Inglis and lower Williston Formations into white to cream

colored, abundantly fossiliferous, chalky limestone of the upper

Williston and Crystal River Formations. Foraminifera, mollusks,

bryozoans, and echinoids are the most abundant fossils occurring

in the Ocala Group. Thickness of the Ocala Group sediments under

Levy County averages about 100 feet. In the vicinity of Gulf

Hammock, and south of Lebanon Station, the Ocala Group thins and

pinches out against the structurally high Avon Park Formation

(see cross section A-A'). Depth to the irregular and highly

solutioned top of the Ocala Group is generally less than 50 feet.






In western Levy County, and offshore of the modern coast, a thin

blanket of sand covers the limestone and exposures in the form of

limestone boulders and pinnacles are common. Surface exposures

are also common east of the Brooksville Ridge on the Williston

Limestone Plain.

The permeable and cavernous nature of the Ocala Group

limestones make them important freshwater bearing units of the

Floridan aquifer system. Many drinking water wells in Levy

County withdraw water from the upper units of this group.

Miocene to Pleistocene Series

Alachua formation (?)

The Alachua formation is a complex and little understood

unit. Originally defined to include only the sand and clay

infillings in older karst depressions or stream channels (Dall

and Harris, 1892), the Alachua formation was later considered to

be a mixture of discontinuous interbedded clay, sand, and sandy

clay, including commercially important phosphatic sand and gravel

deposits (Vernon, 1951; Puri and Vernon, 1964). In Levy County,

the Alachua formation underlies portions of the Brooksville Ridge

and sporadic remnants occupy depressions in the Williston

Limestone Plain and possibly along the northeast edge of the

Chiefland Limestone Plain (Vernon, 1951). The lithology is

highly diverse. On a regional basis, the base of the formation

contains the mineable ore, and is a rubble of phosphatic rock,

silicified limestone float, silicified wood and occasional

vertebrate fossils in a matrix of cream to gray to greenish gray

clays and phosphatic clays (Vernon, 1951); overlying this bed is






a variably thick section of quartz sandy phosphatic clay.

The phosphate rock is a minor constituent of the Alachua

formation, but was economically feasible to mine for many years.

Its mode of occurrence ranges from clay to boulder size clasts as

well as in the form of replacements of limestone and laminated-

phosphate (platerock). Since the Alachua formation was deposited

on the eroded, highly karstic and possibly faulted surface of the

Ocala Group limestones, its thickness varies considerably over

short distances. The mineable deposits are, for the most part,

situated on the eastern flank of the Brooksville Ridge.

Both the origin and age of the Alachua formation are

uncertain. Cooke (1945) considered it an in-situ accumulation of

weathered Hawthorn Group (Miocene) sediments. Puri and Vernon

(1964) believed it originated as a largely terrestrial deposit,

with lacustrine and fluviatile components, and Brooks (1966)

suggested that is was deposited in an estuarine environment.

More recently, Scott (1988, in press) considers the Alachua

formation to be weathered and possibly reworked Hawthorn Group

sediments, although he does not consider it part of the Hawthorn

Group.

An age range of Miocene to Pleistocene, based primarily on

contained vertebrate fossils, has been postulated for the Alachua

formation. This wide age range tends to support the concept of

the Alachua formation being composed of time-transgressive,
reworked sediments, with each successive depositional event

incorporating a younger vertebrate fauna into the sediments.






Plio-Pleistocene Series

Much of the core of the Brooksville Ridge in Levy County is

comprised of reddish, clayey coarse sands, lithologically similar
to the Citronelle Formation of the panhandle, and the Cypresshead

Formation of peninsular Florida; both considered to be Late

Pliocene to Early Pleistocene in age. For the purposes of this

report, these variably-colored red, orange, and pink

siliciclastics, some containing fossil burrows, are placed in the

category of undifferentiated Plio-Pleistocene sediments.

Undifferentiated Pleistocene marine quartz sands and clayey

sands form a thin veneer over all of Levy County. In the western

part of the county and on the Williston Limestone Plain, these

sands are generally less than 20 feet thick, and overlie the

Ocala Group limestone directly; in east central Levy County, they

cap the reddish coarse clastics and where present, the Alachua

Formation. Many of the larger and higher sand bodies in the

county are relict dunes, bars, and barrier islands associated

with various Pleistocene sea level stands. The higher crests on

the Brooksville Ridge, above 100 feet MSL, are associated with

the Sunderland/Okefenokee Terraces (Healy, 1975). Wi.th the

exception of the Suwannee River Valley Lowlands, which are part

of the Pamlico and Silver Bluff Terraces, and the Limestone Shelf

and Plain, which contains Penholoway, Talbot, and Pamlico terrace

deposits, the surficial siliciclastic sediments occurring over
the remainder of Levy County are Wicomico terrace deposits

(Vernon, 1951; Healy, 1975).






the modern coastline, and a series of small islets or keys,

comprised of limestone pinnacles or alluvial sand, are common

offshore of the modern coast.


STRATIGRAPHY

The oldest rock commonly penetrated by water wells in Levy

County is marine limestone of the Eocene age Avon Park Formation.

Undifferentiated Pleistocene to Holocene age surficial sands,

clayey sands, and alluvium are the youngest sediments present.

The Avon Park Formation and the younger overlying limestone units

are important freshwater aquifers, and this discussion of the

geology of. Levy County is confined to these Eocene. age and

younger sediments.


Eocene Series

Avon Park Formation

The Avon Park Formation (Miller, 1986) is a lithologically

variable Middle Eocene carbonate unit underlying all of Levy

County. It is typically a tan to buff to brown dolomite,

frequently interbedded with white to light cream to yellowish

gray limestones and dolomitic limestones, and containing varying

amounts of peat, lignite, and plant remains (Vernon, 1951, and

Florida Geological Survey in-house lithologic files). Mollusks,

echinoids, and foraminifera, where preserved, are the principal

fossils present. The top of the Avon Park Formation varies in

depth from surface outcrop along the crest of the Ocala Platform,

to nearly 150 feet deep in northern and eastern Levy County.

Surface exposures occur in two large areas, one around and west

of the town of Gulf Hammock, and a second extending from just






Holocene Series


Unnamed Freshwater Marl and Alluvium

A white to gray, fossiliferous freshwater marl commonly

occurs along the banks and in the valleys of the Withlacoochee

and Suwannee Rivers. This marl generally contains an abundant

Holocene freshwater mollusk fauna, and may attain three to four

feet in thickness (Vernon, 1951; Puri et al., 1967). Holocene

quartz sand and mud alluvium form bars and floor the valleys of

most major streams in Levy County.

GROUNDWATER

Groundwater is water that fills the pore spaces in

subsurface rocks and sediments. This water is derived

principally from precipitation within Levy and adjoining

counties. The bulk of Levy County's consumptive water is

withdrawn from groundwater aquifers. Two main aquifer systems

are present under Levy County, the surficial aquifer system and

the underlying Floridan aquifer system.

Surficial aquifer system

The surficial aquifer system is the uppermost freshwater

aquifer in Levy County. This non-artesian aquifer is contained

within the interbedded sands and clays of the Alachua formation

and the overlying Plio-Pleistocene siliciclastics and marine

terrace sands in east-central Levy County. In western Levy

County, the surficial aquifer system is thin or absent, occurring

only in locally thick Pleistocene sands immediately overlying the

ocala Group limestone. On average, the surficial aquifer system





;ranges from 10 to 50 feet thick, with the thicker portions

located under the higher geomorphic sand ridges of central and

eastern Levy County. The surficial aquifer system is unconfined,

and its upper surface is the water table. In general, the water

table elevation fluctuates with precipitation rate and conforms

to the topography of the land surface. Recharge to the surficial

aquifer system is largely through rainfall percolating downward

through the loose surficial siliciclastic sediments, and to a

lesser extent, by upward seepage from the underlying Floridan

aquifer system. Water naturally discharges from the aquifer by

evaporation, transpiration, spring flow, and by downward seepage

into the Floridan aquifer system. The surficial aquifer system

may yield quantities of water suitable for consumptive use, but

in some areas the concentration of iron and/or tannic acid impart

a poor taste and color to the water.

Floridan aquifer system

The Floridan aquifer system is comprised of thousands of

feet of Eocene marine limestones, including the Avon Park

Formation and the Ocala Group. It is the principle source of

drinking water in Levy County. The Floridan aquifer system

exists as an unconfined, non-artesian aquifer in portions of

western, northern, and eastern Levy County, where porous

Pleistocene quartz sand directly overlies the limestone. In

areas of east-central and eastern Levy County, where clay beds in

the Alachua Formation and undifferentiat-ed -Pleistocene

siliciclastics form low-permeability confining units, the

Floridan may function as an artesian aquifer. Depth to the top





of the Floridan aquifer generally corresponds to the depth of

limestone, and varies from less than five feet in the Coastal
Marshes and Suwannee and Santa Fe River valleys, to nearly 50

feet under the Brooksville Ridge. The potentiometric gradient is

generally west-southwestward.

Recharge to the Floridan aquifer system in Levy County is

obtained from local rainfall percolating through the permeable

surficial sands in the northwestern and eastern portions of the

county. Low permeability siliciclastics under the Waccasassa

Flats retard downward percolation, resulting in only low to

moderate recharge in this area (Stewart, 1980). In the Limestone

Shelf and Hammocks and in the Coastal Marshes, the potentiometric

surface of the Floridan aquifer system is at or near land

surface, resulting in discharge. Water leaves the Floridan

aquifer system through natural movement downgradient and

subsequent discharge through numerous springs and seeps along the

river valley lowlands and in the hammocks and coastal marsh belt.


MINERAL RESOURCES

The following discussion of mineral commodities is intended

to provide an overview of the extent and mining potential for

each mineral. In Levy County, the principal mineral commodities

are sand, phosphate, limestone, dolomite, and clay.


Sand

A number of shallow private pits in Levy County are worked

for fill sand and aggregate. Pleistocene sand deposits occur as

thin veneers over the limestone plains, and in thicker

concentrations in the marine terrace deposits on and adjacent to






Holocene Series


Unnamed Freshwater Marl and Alluvium

A white to gray, fossiliferous freshwater marl commonly

occurs along the banks and in the valleys of the Withlacoochee

and Suwannee Rivers. This marl generally contains an abundant

Holocene freshwater mollusk fauna, and may attain three to four

feet in thickness (Vernon, 1951; Puri et al., 1967). Holocene

quartz sand and mud alluvium form bars and floor the valleys of

most major streams in Levy County.

GROUNDWATER

Groundwater is water that fills the pore spaces in

subsurface rocks and sediments. This water is derived

principally from precipitation within Levy and adjoining

counties. The bulk of Levy County's consumptive water is

withdrawn from groundwater aquifers. Two main aquifer systems

are present under Levy County, the surficial aquifer system and

the underlying Floridan aquifer system.

Surficial aquifer system

The surficial aquifer system is the uppermost freshwater

aquifer in Levy County. This non-artesian aquifer is contained

within the interbedded sands and clays of the Alachua formation

and the overlying Plio-Pleistocene siliciclastics and marine

terrace sands in east-central Levy County. In western Levy

County, the surficial aquifer system is thin or absent, occurring

only in locally thick Pleistocene sands immediately overlying the

ocala Group limestone. On average, the surficial aquifer system





the Brooksville Ridge. Since there is insufficient local demand

for sand products, the potential for commercial mining is low at
this time.


Phosphate
The phosphatic sands, clays, and limestones of the Alachua

formation deposits along the Brooksville Ridge have been mined

since the 1900's. Hard rock phosphate, a calcium fluorapatite

mixture, occurs as a replacement of limestone float contained in

basal Alachua Formation sediments and on top of the Ocala Group.

The clays within the Alachua Formation contain collodial

phosphate and comprise what is termed soft rock phosphate.

In Levy County, hard-rock phosphate mining has historically

been concentrated along the Brooksville Ridge, and in localized

areas of the Williston Limestone Plain (Vernon, 1951). There are

presently no active mines in the county. While potential

deposits probably still exist under the Brooksville Ridge, future

exploitation of phosphate in Levy County will depend largely on

phosphate market prices and the economic health of the phosphate

industry.


Limestone and Dolomite

Avon Park Formation dolomite occurs near the surface in the

vicinity of Gulf Hammock and southward to near the Levy/Citrus

County line. Two companies currently operate pits near the town

of Gulf Hammock, and the extracted dolomite is used as concrete

aggregate, soil conditioner, and as filler in bituminous mixes

Lane et al., 1988 in press).
Ocala Group limestones occur near the surface under most of





of the Floridan aquifer generally corresponds to the depth of

limestone, and varies from less than five feet in the Coastal
Marshes and Suwannee and Santa Fe River valleys, to nearly 50

feet under the Brooksville Ridge. The potentiometric gradient is

generally west-southwestward.

Recharge to the Floridan aquifer system in Levy County is

obtained from local rainfall percolating through the permeable

surficial sands in the northwestern and eastern portions of the

county. Low permeability siliciclastics under the Waccasassa

Flats retard downward percolation, resulting in only low to

moderate recharge in this area (Stewart, 1980). In the Limestone

Shelf and Hammocks and in the Coastal Marshes, the potentiometric

surface of the Floridan aquifer system is at or near land

surface, resulting in discharge. Water leaves the Floridan

aquifer system through natural movement downgradient and

subsequent discharge through numerous springs and seeps along the

river valley lowlands and in the hammocks and coastal marsh belt.


MINERAL RESOURCES

The following discussion of mineral commodities is intended

to provide an overview of the extent and mining potential for

each mineral. In Levy County, the principal mineral commodities

are sand, phosphate, limestone, dolomite, and clay.


Sand

A number of shallow private pits in Levy County are worked

for fill sand and aggregate. Pleistocene sand deposits occur as

thin veneers over the limestone plains, and in thicker

concentrations in the marine terrace deposits on and adjacent to






Levy County. High purity, road base quality rock, is

concentrated in the Chiefland and Williston Limestone Plains.

Aggregate and secondary road base grades floor the Limestone

Shelf and Hammocks, and the Coastal Marshes of western Levy

County. Three companies currently operate quarries in the

Williston area, and the Levy County Road Department extracts road

base material from small, local pits, on an "as needed" basis.

Due to the extensive deposits of limestone in the county, future

potential for this commodity remains high.

Clay

Localized deposits of clay and sandy clay are associated

with Wicomico and Pamlico Terrace deposits in Levy County

(Vernon, 1951). Most of these deposits are contained in and

interbedded with other sediments, usually on a very irregular

limestone surface. As a result, the clay deposits can vary

considerably in lithology and thickness. Vernon (1951) tested

clays from two locations in Levy County, and reports that both
showed poor strength characteristics, precluding their use in

structural products. However, by mixing the two samples and

adding fluxes, a pottery-grade clay was produced. Reserve

estimates have not been made, and the future exploitation of Levy

County clay deposits will depend largely on more extensive

exploration and testing, as well as market demand.


Limonite
An extensive deposit of Limonite, an iron-oxide mineral,

occupies solution depressions in the Ocala Group limestones in an

area northeast of Chiefland. Vernon (1951) reports a 20-foot





thick section of limonite nodules in a pit east of Chiefland, and

estimates that a reserve of about 50,000 tons is available in the

area. The most feasible use would be as ochre pigment in paint.

Local residents claim that the Confederates operated a smelting

furnace in the area during the Civil War and produced iron from

the deposit (Vernon, 1951).



REFERENCES
Brooks, H., 1966, Geological history of the Suwannee River:
Southeastern Geological Society 12th Annual Field Guidebook, p.
37-45.

Cooke, C. W., 1945, Geology of Florida: Florida Geological
Survey Bulletin no. 29, 339 p.

Dall, W., and Harris, G., 1892, Correlation paper Neocene:
U.S. Geological Survey Bulletin 84, 349 p.

Healy, H., 1975, Terraces and shorelines of Florida. Florida
Bureau of Geology Map Series no. 71.

Lane, E.,7Hoenstine, R. W., Yon, J. W., and Spencer, S. M., 1988
in press, Mineral resources of Levy County, Florida: Florida
Geological Survey Map Series no. 116.

Miller,* J., 1986, Hydrogeologic framework of the Floridan aquifer
system in Florida and in parts of Georgia, Alabama, and South
Carolina: U.S. Geological Survey Professional Paper 1403-B, p.
..25-27.

Puri, H. S., 1957, Stratigraphy and donation of the Ocala Group:
Florida Geological Survey Bulletin no. 38, 248 p.

and Vernon, R. 0., 1964, Summary of the geology of
Florida and a guidebook to the classic exposures: Florida
Geological Survey Special Publication 5 (Revised), 312 p.

Yon, J. W., Jr., and Oglesby, W., 1967, Geology of
Dixie and Gilchrist Counties, Florida: Florida Geological Survey
Bulletin no. 49, 155 p.

Scott ,-T'-M;"--1988--- (in press), The lithostratigraphy of the
Hawthorn Group (Miocene) of Florida: Florida Geological Survey
Bulletin no. 59.

Stewart, J., 1980, Areas of natural recharge to the Floridan
aquifer in Florida: Florida Bureau of Geology Map Series 98.







Tanner, W. F., 1960, Florida coastal classification: Gulf Coast
Association of Geological Societies Transactions, v. 10, p. 259-
266.

Vernon, R. 0., 1951, Geology of Citrus and Levy Counties,
Florida: Florida Geological Survey Bulletin no. 33, 256 p.

White, W., 1970, The geomorphology of the Florida peninsula:
Florida Bureau of Geology Bulletin no. 51, 164 p..





thick section of limonite nodules in a pit east of Chiefland, and

estimates that a reserve of about 50,000 tons is available in the

area. The most feasible use would be as ochre pigment in paint.

Local residents claim that the Confederates operated a smelting

furnace in the area during the Civil War and produced iron from

the deposit (Vernon, 1951).



REFERENCES
Brooks, H., 1966, Geological history of the Suwannee River:
Southeastern Geological Society 12th Annual Field Guidebook, p.
37-45.

Cooke, C. W., 1945, Geology of Florida: Florida Geological
Survey Bulletin no. 29, 339 p.

Dall, W., and Harris, G., 1892, Correlation paper Neocene:
U.S. Geological Survey Bulletin 84, 349 p.

Healy, H., 1975, Terraces and shorelines of Florida. Florida
Bureau of Geology Map Series no. 71.

Lane, E.,7Hoenstine, R. W., Yon, J. W., and Spencer, S. M., 1988
in press, Mineral resources of Levy County, Florida: Florida
Geological Survey Map Series no. 116.

Miller,* J., 1986, Hydrogeologic framework of the Floridan aquifer
system in Florida and in parts of Georgia, Alabama, and South
Carolina: U.S. Geological Survey Professional Paper 1403-B, p.
..25-27.

Puri, H. S., 1957, Stratigraphy and donation of the Ocala Group:
Florida Geological Survey Bulletin no. 38, 248 p.

and Vernon, R. 0., 1964, Summary of the geology of
Florida and a guidebook to the classic exposures: Florida
Geological Survey Special Publication 5 (Revised), 312 p.

Yon, J. W., Jr., and Oglesby, W., 1967, Geology of
Dixie and Gilchrist Counties, Florida: Florida Geological Survey
Bulletin no. 49, 155 p.

Scott ,-T'-M;"--1988--- (in press), The lithostratigraphy of the
Hawthorn Group (Miocene) of Florida: Florida Geological Survey
Bulletin no. 59.

Stewart, J., 1980, Areas of natural recharge to the Floridan
aquifer in Florida: Florida Bureau of Geology Map Series 98.







I : ALACHUA COUNTY
", ,i.JM^


EXPLANATION

3 TOWN
SU.S. HIGHWAY
-- STATE/COUNTY: ROAD
0 WELL LOCATION
O. CROSS SECTION LOCATION
SGEOMORPHIC ZONES
z MODIFIED AFTER RERNON(1951) AND WHITE(1970).
o CENTRAL HIGHLANDS
z WESTERN VALLEY -
o WILLISTON LIMESTONE PLAIN
< BROOKSVILLE RIDGE

GULF COASTAL LOWLANDS

Di WACCASASSA FLATS
LIMESTONE SHELF
S AND HAMMOCKS

CHIEFLAND LIMESTONE PLAIN

SUWANNEE RIVER VALLEY
LOWLANDS
B m COASTAL MARSHES


CITRUS COUNTY




















A

0)




-50 CHIFLCAN LIMESTONE
PLAIN


0 0 GEa


OCALA
-so50


-20




-40




-60'


-L~C~


-100



-150



-200
VERTICAL EXAGGERATION IS
SO TMS TUE SCALE.
WELL NUMBERS ARE FLORIDA GEOLOGICAL
SURVEY aCCESSION NUMBERS.


GROUP


AVON






T.D0.440 FEET


UNDFFERENTIATED
SANDS


PARK


LIMESTONE PLAN

AND HAMOOCOK


FORMATION


MILES
012345
SCALE '. 'L_' l'
0 2 4 6 8
KILOMETERS


rT.D. "6 FEET


-


'* *..'r. '




























NDiFEqENTIATED


0
O I ,,,
to I ROOKSVILLE
S O RIDGE


-20


-100
-40
t150


-860
-200
VERTICAL EAOO 4N I 350 T
WELL NUESL 10 ARE 350 P ,'O S TRUE SCALE.
"UCESRSO ARE FLORIO1 GEOLOGICAL Su-Vey
ACCESIIOr4NUMBIAS..


MILES
SCALE

KILOMETERS


r..-600o FEET


'rOD..~ Peerr


a':.


FORMATION'


AVON










FLRD GEOLOSk ( IC SUfRiW


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