FLORIDA GEOLOGICAL SURVEY


Contour Interval Selection

 Contour intervals for each map were selected
based on the mean of the ASE for each
respective krige model trimmed to the map unit
extents (Table 3 Footnote 2). If one assumes
normality, the ASE of the prediction error is
essentially the standard deviation (s) of the
interpolated surface and represents a 68 percent
level of significance. If one were to double the
error (i.e., 2s), a 95 percent level of significance
is achieved. To avoid inflating implied accuracy
of the krige surfaces, the contour interval for all
but two maps was selected between Is and 2s.
In other words, the selected contour interval is
always greater than or equal to the mean of the
ASE prediction error, except for the IAS/ICU
thickness map and the MFCU surface map. Per
Table 3, the error for these maps is over-
predicted. For every contour map in this study,
the standard deviation for the "Grid to Point"
calculation described above (Table 3) is less
than the contour interval.

 STRATIGRAPHY

 The stratigraphic framework of the west-
central Florida peninsula, encompassing the
SWFWMD region, is presented from north to
south in the following geographic subdivisions:
northern region (eastern Levy, western Marion,
Citrus, Sumter, western Lake, Hernando and
Pasco Counties), central region (including
Pinellas, Hillsborough, western Polk, Manatee
and Hardee Counties), southern region
(Sarasota, DeSoto and Charlotte Counties) and
the eastern region (e.g., the Lake Wales Ridge,
including eastern Polk and Highlands Counties).
The framework discussion is subdivided into
lithostratigraphy and hydrostratigraphy, and is
characterized through a series of cross sections
and maps (surfaces and thicknesses). East-west
trending cross sections presented in this report
(see Plate 1 for locations) are ordered from the
north to south (i.e., the northern to southern
regions; Plates 4-19), then north to south within
the eastern region (Plates 20-28). Cross sections
trending north-south are ordered from west to
east as follows: Plates 29 and 30 in the northern
region, Plates 31-35 in the central/eastern
regions and Plates 36 and 37 in the southern


region. Maps of lithostratigraphic units are
presented from oldest to youngest (Plates 38 -
54) and hydrostratigraphic units are presented
from shallow to deep (Plates 55 59).


 Lithostratigraphy

Introduction

 Structure contour (surface) and isopach maps
(thickness) in this report include Lower Eocene
through Lower Pliocene lithostratigraphic units,
which are described in detail in this section.
Characterization of the mapped units includes
age, lithology, mineralogy, porosity, significant
fossils, distribution, nature of vertical and lateral
contacts, distinguishing gamma-ray activity
responses, relation to hydrostratigraphic units
and environment of deposition. Superjacent and
subjacent lithostratigraphic units (i.e., the
Oldsmar Formation) are also presented.

Eocene Series

 Oldsmar Formation

 The Lower Eocene Oldsmar Formation
("Oldsmar Limestone" of Applin and Applin,
1944) underlies the entire Florida peninsula.
Miller (1986) describes the Oldsmar Formation
as a white to gray limestone with variably thick
interbeds of gray to light brown, crystalline
dolostone that increases in abundance with
depth. Thin beds of chert and evaporites,
including pore-filling gypsum occur within the
unit (Miller, 1986). Reese and Richardson
(2008) report a glauconite marker horizon that
occurs intermittently within upper -200 ft (~ 61
m) of the Oldsmar Formation in the study area.
Porosity types include intergranular,
intragranular and fracture (e.g., "Boulder
Zone"). Braunstein et al. (1988) indicate that
the unit may have an unconformable contact
with the subjacent Cedar Keys Formation;
however, the contact with the overlying Avon
Park Formation is possibly conformable.

 In the study area, the Oldsmar Formation
limestones vary from packstone to wackestone.