Title Page
 Maps and charts

Geology of DeSoto County, Florida ( FGS: Open file report 11 )
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00001010/00001
 Material Information
Title: Geology of DeSoto County, Florida ( FGS: Open file report 11 )
Series Title: ( FGS: Open file report 11 )
Physical Description: 9, 4 p. : ill., maps ; 28 cm.
Language: English
Creator: Campbell, Kenneth M ( Kenneth Mark ), 1949-
Florida Geological Survey
Publisher: Florida Geological Survey
Place of Publication: Tallahassee Fla
Publication Date: 1985
Subjects / Keywords: Geology -- Florida -- De Soto County   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: by Kenneth M. Campbell.
Bibliography: Includes bibliographical references (p. 9).
General Note: Cover title.
 Record Information
Source Institution: University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: aleph - 001545490
oclc - 22438840
notis - AHF9010
System ID: UF00001010:00001

Table of Contents
    Title Page
        Title Page 1
        Title Page 2
        Page 1
        Page 2 (MULTIPLE)
        Page 3
        Page 4
        Page 5
        Page 6 (MULTIPLE)
        Page 7
        Page 8
        Page 9
    Maps and charts
        Page 10
        Page 11
        Page 12
        Page 13
Full Text


[year of publication as printed] Florida Geological Survey [source text]

The Florida Geological Survey holds all rights to the source text of
this electronic resource on behalf of the State of Florida. The
Florida Geological Survey shall be considered the copyright holder
for the text of this publication.

Under the Statutes of the State of Florida (FS 257.05; 257.105, and
377.075), the Florida Geologic Survey (Tallahassee, FL), publisher of
the Florida Geologic Survey, as a division of state government,
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All uses, excluding those made under "fair use" provisions of U.S.
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restricted. Contact the Florida Geological Survey for additional
information and permissions.

State of Florida
Department of Natural Resources
Elton J. Gissendanner, Executive Director

Division of Resource Management
Charles W. Hendry, Jr., Director

Florida Geological Survey
Steve R. Windham, Chief

Open File Report 11

Geology of DeSoto County, Florida


Kenneth M. Campbell

Florida Geological Survey
Tallahassee, Florida

3 1262 04543 6317



Geology of DeSoto County, Floridat Ge
Florida Bureau ot Geology ta
BY 903 %.Tennsee st
Tahas FL 32304
Kenneth M. Campbell
Florida Geological Survey
Tallahassee, Florida


Several authors have discussed the physiography of the Florida peninsula.

For the purposes of this report, White's (1970) classification will be utilized.

The vast majority of DeSoto County lies within the DeSoto Plain (Fig. 1). Por-

tions of the southwest corner of the county fall within the boundaries of the

Gulf Coastal Lowlands.

Elevations within the county range from very near sea level in the southwest

corner along the lower Peace River valley, to 90-95 feet in the northeast corner

of the county. Elevations increase almost imperceptably from the southwest

toward the northeast. The topography tends to be flat with relatively steeper

slopes in the vicinity of streams. Much of the interstream area is poorly

drained. Many swamps, marshes and ponds are present throughout the county. The

Peace River, Horse Creek and Joshua Creek are the major streams within the county.

DeSoto Plain

The DeSoto Plain is a very flat area located primarily in Manatee, Hardee,

DeSoto, Highlands, Glades and Charlotte counties. White (1970) believes that

the DeSoto Plain is a submarine plain probably formed under Pleistocene Wicomico

seas (70 100 feet above present sea level). White (1970) cites the notable

absence of relict shoreline features as evidence of the submarine origin of the

DeSoto Plain.

Gulf Coastal Lowlands

The southwest corner of DeSoto County is located within the Gulf Coastal

Lowlands (White, 1970). The prominent topographic features of the Gulf Coastal

Lowlands within DeSoto County include scarps and terraces developed during

Pleistocene sea level stands and the entrenched Peace River Valley. Healy

(1975a) shows two terraces within the Gulf Coastal Lowlands portion of DeSoto

County. The Pamlico terrace is found at elevations of approximately 8-25 feet

above mean sea level; the Talbot at 25-42 feet. Both of these terraces extend

up the entrenched Peace River Valley. Except within the Peace River Valley,

these "terraces" are poorly defined elevation zones. The flood plain of the

Peace River lies as much as 30 feet below the surrounding upland surface in this



Surface and near surface sediments in DeSoto County consist of quartz sand,

clay, limestone and dolomite. These sediments range in age from Oligocene

(38-22.5 million years ago) to Holocene (10,000 years ago to present).

Oligocene Series

Suwannee Limestone

The Suwannee Limestone is present throughout DeSoto County in the subsurface.

The Suwannee Limestone is a creamy white to light yellowish grey limestone,

variably textured (wackestone to packstone), poorly to well indurated and variably

recrystalllzed. The upper portions are highly fossiliferous (predominantly

poorly preserved foraminifera, with molluscs, echinoids and corals). Moldic

and vuggy porosity is common.

The top of the Suwannee Limestone is encountered at approximately 350 feet

below mean sea level in the northeastern and northwestern corners of the county,

and dips generally to the south and south-southeast. In the southeastern corner

of the county, the top of the Suwannee Limestone is encountered at depths of

approximately 700 feet below mean sea level (Scott, in press; Wilson, 1977).

The thickness of the Suwannee ranges from approximately 140 feet to over


400 feet within the county (Wilson, 1977). The thinnest portion is in extreme

northeastern DeSoto County, while the thickest portion is along the central por-

tion of the western edge of the county.

Miocene Series

Hawthorn Group

Scott (in press) has raised the Hawthorn from formation status to group status.

The Hawthorn Group will include those sediments which in the past have been

included in the Tampa, Hawthorn and Bone Valley formations. In DeSoto County,

the Hawthorn Group consists of, in ascending order, the Arcadia Formation and

the Peace River Formation.

Arcadia Formation

The Arcadia Formation (Scott, in press) is named after the town of Arcadia

in DeSoto County. The type section designated by Scott (in press) is located in

the core W#12050 (see Figure 4) between -96 feet M.S.L. and -216 feet M.S.L.

The Arcadia Formation contains, in ascending order, the Nocatee and Tampa members

and an unnamed member.

The Nocatee Member of the Arcadia Formation is named for the town of

Nocatee in central DeSoto County and is present throughout DeSoto County. The

sediments included in the Nocatee have previously been called the "sand and clay
unit" of the Tampa Limestone (Wilson, 1977).

Lithologically, the Nocatee consists of a complexly interbedded sequence of

variably phosphatic quartz sands, clays and carbonates (Scott, in press). The

Nocatee is predominantly a plastic (sand and clay) unit. Quartz sands are typi-

cally fine to coarse grained, sometimes silty, clayey, calcareous or dolomitic

and variably phosphatic (Scott, in press). Clay beds are common. The clays are

variably quartz sandy and silty, phosphatic and calcareous to dolomitic.

Carbonate beds are subordinate within the Nocatee (Scott, in press).

The top of the Nocatee Member of the Arcadia Formation within DeSoto County

is encountered at elevations which range from approximately -200 feet M.S.L. to

approximately -450 feet M.S.L. (Scott, in-press). .The.upper surface dips to the

south and south-southeast. The thickness of the Nocatee within the county

ranges from approximately 125 to slightly more than 200 feet.

The Tampa Member of the Arcadia Formation is lithologically similar to the

type Tampa Formation of King and Wright (1979), but has a slightly greater phos-

phate content (1-3 percent) and greater area extent (Scott, in press). The

Tampa Member is a white to tan-colored, quartz sandy limestone with a carbonate

mud matrix. Varying amounts of clay are usually disseminated throughout the

rock (King and Wright, 1979; Scott, in press). Some beds within the Tampa

Member contain more than 50 percent quartz sand. Dolomite is relatively uncom-

mon within the Tampa Member (King and Wright, 1979; Scott, in press).

The Tampa Member is recognizable throughout most of DeSoto County, however

the unit becomes indistinct due to a faces change in eastern DeSoto County and

south of the DeSoto/Charlotte county line (Scott, in press).

The top of the Tampa Member is encountered between 150 and 200 feet

below mean sea level in DeSoto County (Scott, in press). Thickness of the Tampa

ranges from 50 to 100 feet (Scott, in press).

The upper (unnamed) member of the Arcadia Formation includes those sedi-

ments which in the past have been referred to as the "Hawthorn carbonate unit"

(Scott, in press). Lithologically, these sediments consist of white to yellow-

ish grey, quartz sandy, phosphatic and sometimes clayey, dolomites and lime-

stones (uncommon). Occasional beds of carbonate rich quartz sand and thin clay

beds are present.

The upper member of the Arcadia is present throughout DeSoto County. In

those areas where the Tampa and Nocatee Members are not recognized, the entire

formation remains undifferentiated. The top of the Arcadia Formation ranges

from near mean sea level in the northern part of the county to slightly more

than 100 feet below mean sea level and dips generally in a south-southeast

direction. Where the Arcadia is differentiated, the upper member is approxima-

tely 100 to 140 feet thick. The thickness of the entire Arcadia Formation,

within the county, ranges from slightly less than 300 feet to more than 500 feet

(Scott, in press).

Peace River Formation

The Peace River Formation (Scott, in press) in DeSoto County consists of

those sediments which have been described in the past, as "upper Hawthorn

clastics." The type section designated by Scott (in press) is well #12050

(section 16, township 38S, range 26E, DeSoto County) between +41 and -97 feet

MSL. Lithologically, these sediments consist of yellowish-grey to light olive

green interbedded phosphatic sands, clayey sands, clays and dolomite stringers.

The top of the Peace River Formation is found at or near mean sea level

throughout much of the county (Scott, in press). In northwestern DeSoto County,

however, the Peace River Formation is encountered at 50 feet above mean sea

level. The base of the Peace River is gradational with the underlying Arcadia

Formation, and is picked at the point where the sediments change from predomi-

nantly plastic to predominantly carbonate (Scott, in press).

The thickness of the Peace River Formation is approximately 50 feet in the

northeastern and southwestern corners of the county. The Peace River thickens

to more than 160 feet in the southeastern corner of the county. The Peace River

dips, and thickens in a general south easterly direction.

Pliocene-Pleistocene Series

Undifferentiated Surficial Sands and Shell

Surficial deposits of Pliocene-Pleistocene age (5.3 to .01 million years

ago) blanket the county. Throughout the majority of the county, the surficial

deposits consist of silty, clayey, shelly sands and variably indurated shell

beds. The shell beds are generally limited to the southern third of the county.

The undifferentiated surficial sands and shell range from 10-30 feet thick

throughout the majority of the county. Surficial sediments thicken in the south

central portion of the county and along the DeSoto/Highlands county line.

Clean quartz sand of Pleistocene age (1.6 to..01 million years ago) forms a

veneer over the clayey shelly sands. These deposits consist of unconsolidated

very fine to medium grained quartz sand. The sands are white to light brown in

color and contain trace amounts of phosphate sand and limestone or shell


Holocene Series

Deposits of Holocene age (10,000 years ago to present) are primarily

limited to present day stream flood plains, beaches, swamps, marshes and lakes.

these sediments consist of sand, silt, clay and organic materials.


Groundwater in DeSoto County is obtained from the surficial aquifer system,

the intermediate aquifer system and from the Floridan Aquifer. The aquifers are

separated by confining layers which restrict vertical water movement between the

aquifer systems.

Surficial Aquifer System

The surficial aquifer consists primarily of quartz sand and includes the

undifferentiated surficial sands and shell as well as the uppermost portions of

the Peace River Formation. With the exception of some lithified shell beds,

these sediments are unconsolidated.

The top of the surficial aquifer is the ground water table and water within

the surflcial aquifer is generally under unconfined conditions. The base of the


surficial aquifer system is formed by the clayey, less permeable beds of the

Peace R'iver Fotmation'"The surficial aquifer system underlies essentially all

of DeSoto County and is utilized primarily for domestic, lawn irrigation and
stock watering supplies, where high flow notes are not required (Wilson, 1977).

Intermediate Aquifer System

The intermediate aquifer system contains water under confined conditions

and consists primarily of the .limestones and dolomites of the Arcadia Formation.

The intermediate aquifer corresponds with the "upper unit of the Floridan

Aquifer" of Wilson (1977). The upper confining layer of the intermediate

aquifer system consists of the clayey sediments of the Peace River Formation.

The lower confining layer consists of the Nocatee Member of the Arcadia


Within DeSoto County, the intermediate aquifer averages approximately 200
feet in thickness (Wilson, 1977). Typical wells yield up to several hundred

gallons per minute, however, yield is highly variable (Wilson, 1977). The prin-

cipal uses for wells developed in the intermediate aquifer are for domestic and
public supply.

Floridan Aquifer

The Floridan Aquifer consists of the limestones and dolomites of the
Suwannee Limestone and the underlying Ocala Group and Avon Park Limestone. The

Floridan contains water under confined conditions. In DeSoto County, the upper

confining layer consists of the Nocatee Member of the Arcadia Formation. The

top of the Floridan is encountered at approximately 300 feet below mean sea

level in the northwestern corner of the county and dips to approximately 750

feet below mean sea level in the southeastern corner (Buono and Rutledge, 1978).

Wells developed in the Floridan Aquifer yield large quantities of water,

often in excess of 1000 gallons per minute (Wilson, 1977). The primary use of


water from the Floridan Is large scale inigation. Water quality of the Floridan

Aquifer is generally poorer than in the surficial and intermediate aquifers.

Water quality In both the Floridan and the intermediate aquifer decreases in a

general southwesterly direction (Wilson, 1977).

Areas of Artesian Flow

Both the intermediate and the Floridan aquifers are under confined con-

ditions and may contribute to artesian flow. Healy (1975b) shows the south-

western portion of the county as an area of artesian flow. This area emcom-

passes the entire Peace River Valley, portions of the Horse Creek and Joshua

Creek drainages and the Gulf Coastal Lowlands as well as the southwestern edge

of the DeSoto Plain. Barr and Schiner (1983) show potentiometric surface eleva-

tions of 40-50 feet above mean sea level for much of the same area.

-_ -


Barr, G. L., and Schiner, G. R., 1983, Potentiometric surface of the Floridan
Aquifer, Southwest Florida Water Management District, May, 1983, U. S.
Geol. Survey, O.F.R. 83-547.

Buono, A., and Rutledge, A. T., 1978, Configuration of the top of the Floridan
Aquifer, Southwest Florida Water Management District, and adjacent areas,
U. S. Geol. Survey, Water Resources Investigation 78-34.

Healy, H. G., 1975a, Terraces and shorelines of Florida, Florida Bureau of
Geology, Map Series #71.

1975b, Piezometric map with the area of artesian flow of the
Floridan Aquifer in Florida, Revised 1975, Florida Bureau of Geology, Map
Series #4 Revised.

King, K. C. and Wright, R., 1979, Revision of the Tampa Formation, west-central
Florida, Transactions, Gulf Coast Association of Geological Societies, vol.
XXIX, pp. 257-261.

Scott, T. M., 1985, The regional lithostratigraphy of the Hawthorn Group Miocene
of Florida, Florida Bureau of Geology, Bull. #59, manuscript in press.

White, W. A., 1970, Geomorphology of the Florida peninsula, Florida Bureau of
Geology, Bull. #51, 164p.

Wilson, W. E., 1977, Ground water resources of DeSoto and Hardee Counties,
Florida, Florida Bureau of Geology, Report of Invest. #83, 102p.

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