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FGS040692
OPEN FILE MAP SERIES No. 10
FLORIDA GEOLOGICAL SURVEY
DEPARTMENT OF NATURAL RESOURCES
GEOLOGIC MAP OF CITRUS COUNTY
by
K Campbell, PG #192 andT Scott PG # 99
RI5E + R16E
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GEOLOGIC MAP OF
CITRUS COUNTY
FLORIDA
BY
K. Campbell, PG.# 192 and T Scott, PG.# 99
1992
HERNANDO COUNTY
R17E +
THIS IS AN INTERIM GEOLOGIC MARP
EDITING AND EDGE MATCHING HAVE
NOT BEEN COMPLETED. UPDATING
AND CORRECTING ARE CONTINUING.
WALTER SCHMIDT
STATE GEOLOGIST AND CHIEF
S T HERNANDO CO UN
QTu Th Th
RISE +E
+
R18E
R19E
f
SR20E
+ R21 E
geologydespite an often pare data base As a general rule if
the undifferentiated sedment were less than 20feet thick the
underlying recognizable formation wa mapped
ParkFormation underlie theentire county but exposed only n
a small portion of north western Citru County and consists of
dolostoneand silt sized dolomite The dolostone is often micro
.. .. .. ..- en
overlain by the Upper Eocene Omla Limestone (To)
county and in the Tsala Apopka Plain in the eastern portion of the
county The Oala Limestone consists of very pure, highly
Limestone (T), weathered Hawthorn sediments (Twh), unnamed
Quaternary dune sands (Qd) or un differentiated sediments (Ou)
portion of the county The Suwannee consists of fossliferous
beds,predominantly in the lower portionof the unit The Suwannee
Limestone is unconformably overlain by the Hawthorn Group, by
weathered/reworked Hawthorn sediment, or by undifferentiated
sediments
The Miocne Hawthorn Group (Th) is present only as small
consit of clays, clayey sands and sandy clayey limestones all
of whichmaybephosphatic TheHawthornisoverlainby
eathered/reworked Hawthorn sediments or by undifferentiated
sediments
Weathered Hawthorn sediments (Thw) form the bulk ofthe
sediments are overlain by variable thicknesses of undifferentiated
sediments
dune characteristcs
I I I
I I I I
R17E +
R19F
R20E
+ R21E
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T 18 S29 00' 28 40'82 10' 82 20' 82 30' 82 40' R 21 E R 20 E R 19 E R 18 E R 17 E R 16 E R 15 ET 21 S T 20 S T 19 SCARTOGRAPHY BY JIM JONES AND TED KIPER 28 50' T 17 S T 16 S 29 00' 28 50'T 16 S T 17 S T 19 S T 20 S T 21 S T 18 S 82 40' 82 30' 82 20' 82 10' R 15 E R 16 E R 17 E R 18 E R 19 E R 20 E R 21 E Lake HendersonWithlacoochee Riverl581l581l581l480 480l480l100l491l491l l491l491 200l l490 490l494l488l495l45l48l45l45l45l44l35l l55 55l55l l44 19o o41o41o41o98 H E R N A N D O C O U N T Y H E R N A N D O C O U N T YS U M T E R C O U N T YM A R I O N C O U N T Y L E V Y C O U N T Y Withlacoochee RiverWithlacoochee River N SCALE4 MILES 3 2 1 0.5 0 6 KILOMETERS 5 4 3 2 1 0 QTu Thw To THIS IS AN INTERIM GEOLOGIC MAP. EDITING AND EDGE MATCHING HAVE NOT BEEN COMPLETED. UPDATING AND CORRECTING ARE CONTINUING. QTu Th Ts Th Ts QTu To Qd Qd To Ts Th To Ts QTu Thw To To ToOPEN FILE MAP SERIES No. 10 FGS040692Qu To Qd Tap Qd QTu To To Ts To Thw To Thw GEOLOGIC MAP OF70SE STATE GEOLOGIST AND CHIEF WALTER SCHMIDT.T19K. Campbell, P.G.# 192 and T. Scott, P.G.# 99To To To C IGOLOEIRLFO GAD LA1992 YUEVR SCITRUS COUNTYBYFLORIDA Weathered Hawthorn sediments (Thw) form the bulk of the Brooksville Ridge in Citrus County. These sediments have been called the "Alachua Formation" in the past and consist primarily of red, orange and light yellow variably clayey sands. These sediments are highly leached, clays are predominantly kaolin and phosphate grains have generally been removed. Hard rock phosphate deposits are common associated with karst features along the eastern ank of the Brooksville Ridge. Weathered Hawthorn sediments are overlain by variable thicknesses of undierentiated Quaternary dune sands (Qd) are present along the western ank of the Brooksville Ridge. Only those areas with a recognizable dune morphology are mapped as dunes. Undierentiated Quaternary sediments (Qu) indicate areas with thick sands which do not exhibit sediments. dune characteristics. sediments.DEPARTMENT OF NATURAL RESOURCES FLORIDA GEOLOGICAL SURVEYunderlying recognizable formation was mapped. The oldest stratigraphic unit mapped in Citrus County is the early Tertiary Middle Eocene Avon Park Formation (Tap). The Avon Park Formation underlies the entire county but is exposed only in a small portion of north-western Citrus County and consists of dolostone and silt sized dolomite. The dolostone is often micromoldic and highly recrystallized. The silt sized dolomite is often very soft to unconsolidated. The Avon Park is unconformably The Upper Eocene Ocala Limestone is found at or near the land surface in the coastal lowlands in the western one third of the county and in the Tsala Apopka Plain in the eastern portion of the county. The Ocala Limestone consists of very pure, highly fossiliferous grainstones and packstones. Predominant fossils include large and small foraminifera, molluscs, echinoids and bryozoans. The Ocala is unconformably overlain by the Suwannee Limestone (Ts), weathered Hawthorn sediments (Twh), unnamed Quaternary dune sands (Qd) or undierentiated sediments (Qu). The Oligocene Suwannee Limestone (Ts) is found within the Brooksville Ridge, forming the tops of some of the hills in the central portion of the county and in a broader area in the southern portion of the county. The Suwannee consists of fossiliferous packstones and occasional grainstones which are slightly quartz sandy, variably recrystallized and which commonly contain chert beds, predominantly in the lower portion of the unit. The Suwannee Limestone is unconformably overlain by the Hawthorn Group, by weathered/reworked Hawthorn sediments, or by undierentiated The Miocene Hawthorn Group (Th) is present only as small outliers capping some of the highest hills in the central portion of the county and in the southern part of the county. The Hawthorn consists of clays, clayey sands and sandy, clayey limestones, all of which may be phosphatic. The Hawthorn is overlain by weathered/reworked Hawthorn sediments or by undierentiated sediments. overlain by the Upper Eocene Ocala Limestone (To). K. Campbell, P.G.# 192 and T. Scott, P.G.# 99 The geologic map of Citrus County, Florida was developed as a generalized base map to be utilized in predicting radon potential hazards. Funding for this eort was provided by the U. S. Environmental Protection Agency (EPA) and the Florida Department of Community Aairs. The geology of the county was mapped utilizing well cuttings, cores, natural and man-made exposures and topographic maps. Geologic units identied include formal lithostratigraphic units and informal units. Both types of units were utilized in order to provide a more accurate picture of the geology despite an often sparse data base. As a general rule, if the undierentiated sediments were less than 20 feet thick, the GEOLOGIC MAP OF CITRUS COUNTY by
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