Information Circular 107


PETROLOGY AND PROVENANCE OF THE NORPHLET FORMATION,
 PANHANDLE, FLORIDA

 By
 Greg W. Scott


 INTRODUCTION

 Several authors have published data on the
petrologic character of the Upper Jurassic
Norphlet Formation in Mississippi and Alabama
(Hartman, 1968; Badon, 1975; McBride, 1981;
Mancini et al, 1984). This study is primarily
confined to areas of Norphlet deposition
previously undocumented, namely Escambia,
Santa Rosa, and Okaloosa Counties, Florida
(Figure 1, Table 1). Throughout panhandle
Florida, the Norphlet Formation is encountered at
depths usually greater than 13,000 feet below
mean sea level. The formation underlies most of
the study area except eastern-most Okaloosa
County, where it wedges out. The Norphlet
unconformably overlies the Louann, Werner, or
Eagle Mills Formations (Oxley et al, 1967;
Mancini et al, 1984). Lying above the Norphlet
Formation sandstones and making an abrupt
lithologic break are carbonates of the Smackover
Formation (Sigsby, 1976) (Figure 2).
 Most of panhandle Florida is located within the
Conecuh Embayment which, in turn, is situated
within the Alabama Interior Salt Basin. The
Conecuh Embayment, as defined by Sigsby
(1976), lies between the pre-Jurassic Conecuh
Ridge to the north and the Pensacola Arch to the
southeast, both of which probably served as
source areas for Norphlet sediments (Figure 3).


 NORPHLET FORMATION OF
 PANHANDLE FLORIDA

 The Norphlet Formaiion varies considerably in
 lithologic character across panhandle Florida. In
 central Escambia and Santa Rosa Counties, the
 upper Norphlet Denkman Member (informally
 subdivided into upper and lower units) is
 characterized by relatively clean, light-colored


sandstones (Tyrrell, 1973). Core material
available for this study is concentrated within this
quartzose lithofacies because the member lies
just below the more productive Smackover
Formation and therefore is more frequently cored
than other lithofacies.
 The Pensacola Arch trends southwest through
Okaloosa County and across southern Santa
Rosa and Escambia Counties (Figure 3).
Placement of the arch this far west is based upon
the overall subsurface trend of structural features
and stratigraphic sequences and geophysical
well logs interpreted for this project. It is against
this arch that the relatively clean sandstones of
the Denkman Member thin and grade into
medium- to coarse-grained and gravelly
sandstones.
 In southern Santa Rosa County, the formation
 is represented by a 14.6-foot section of
 conglomerates and coarse grained sandstones
 (Getty Oil Company, Florida permit 1097),
 interpreted to lie on top of or adjacent to the
 Pensacola Arch. The conglomeratic sands
 contain granule- to cobble-sized igneous and
 metamorphic clasts. Mancini et al, (1985)
 identified chert, granite, rhyolite, quartzite, and
 shale pebbles within this conglomerate
 lithofacies in southern Alabama.
 In western Okaloosa County (Champlin
 Petroleum Company well, Florida permit 518),
 the Norphlet Formation is characterized by
 coarse, red, lithic sandstones (red beds), which
 probably represent a transition from the
 conglomerate deposits over the Pensacola Arch.
 The formation thins dramatically east of this well
 and wedges out completely within approximately
 16 miles. In southern Santa Rosa County, the
 Norphlet Formation represented within the Belco
 Petroleum Corporation well core (Florida permit
 692) exhibits a red bed lithofacies at its base.
 A discontinuous basal shale sequence has
 been identified within Norphlet cored sections in