Information Circular 107


(Figure 15). Geopetal infilling by Norphlet
sediments probably occurred after meteoric
leaching of the then-exposed anhydrite. Finally,
calcite-saturated waters infiltrated the cavities
and precipitated the calcite caps.
 The preserved lower Norphlet portion of the
core is an interlayered section of conglomeratic
and coarse-grained sandstones. At the top of
the core is a two-inch zone of coarse-grained
sandstone overlying approximately three feet of
conglomerate. The sandstones are red and the
grains are moderately sorted and subangular to
subrounded. The conglomeratic material is dark
gray in color, poorly sorted, with angular to
rounded grain shapes. Large rock fragments
within the conglomerate consist of pebble- to
cobble-sized grains, some up to three inches
across. These large rock fragments are dark
green, white, and dark gray, subangular to
subrounded, and appear to be plutonic and
metamorphic in origin. Mancini et al, (1984)
identified pebbles of shale, chert, quartzite,
granite, and rhyolite in conglomerates from
Escambia County, Alabama, farther to the north
than these Florida conglomerates. Differences in
composition between these Pensacola Arch
conglomerates and their northern counterparts
are believed to be due to the proximity and type
of source materials available to each. Lying
directly below the three-foot zone of gray
conglomerate is another interval of coarse, red
sandstone about one- to two-inches thick. Below
this sand the lithology again changes to a 2.0- to
2.5-inch thick conglomerate lying on a "dirty"
white, crystalline, coarse-grained, wavy-
laminated anhydrite.


 PROVENANCE OF NORPHLET SEDIMENTS

 Interpretation of petrographic and stratigraphic
 data can give a general indication of source
 areas for Norphlet sediments. Mineral
 composition of Norphlet sediments varies
 moderately across panhandle Florida. Although
 compositional differences do exist, essentially


the same constituents are present throughout all
cores, including quartz, feldspars, and
sedimentary, igneous, and metamorphic rock
fragments. The similarity in mineralogy in all
lithofacies of the formation indicates that the
source areas remained constant throughout
Norphlet deposition (Wilkerson, 1981).
 Walls (1985) used locations of samples which
had the highest amount of labile grains to
indicate source areas of the Norphlet Formation
of southern Alabama. He noted that MRFs
dominate updip Alabama Norphlet sediments,
but diminish to the south. The labile nature of
the fragments suggests that the nearby southern
Appalachian uplands served as a source area for
these MRFs. Compositional variation maps,
constructed by Walls (1985), indicate a
southwesterly dispersal pattern for these
sediments. This direction would imply significant
deposition of MRFs in the Manila Embayment,
separated from panhandle Florida by the
Conecuh Ridge (Figure 3). Both the Manila
Embayment and the Conecuh Ridge probably
restricted much of this debris from panhandle
Florida. Additionally, Walls (1985) noted a
significant compositional difference between
samples from northern counties and samples
from Mobile, Escambia, and Conecuh Counties,
Alabama. Samples from the southern counties
have a higher lithic content, higher feldspar
concentration, and appear to have accumulated
from several directions, indicating at the very
least a southern source (Walls, 1985).
 Ottman et al, (1973) and Sigsby (1976)
 suggested that the Conecuh Ridge and
 Pensacola Arch were topographic highs during
 much of Norphlet deposition, outlining the
 Conecuh Embayment. All Norphlet sediments of
 panhandle Florida are located within this basin,
 which is bordered to the north by the Conecuh
 Ridge, to the east and south by the Pensacola
 Arch, and to the southwest by the Wiggins Arch.
 The Conecuh Ridge and Pensacola Arch
 probably served as source areas for Florida
 Norphlet sediments (Sigsby, 1976). It is the
 author's opinion that sediments derived from the


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