Stratigraphy and Petroleum Potential of Peninsular Florida and Southern Georgia: ABSTRACT

Abstract

Cretaceous and Tertiary sediments, with a maximum thickness of about 8,000 ft in southwestern Georgia and 18,000 ft in the South Florida basin, are present under all of the area south of the Appalachian Piedmont belt of Precambrian (?) crystalline rocks. In addition, flat-lying early Paleozoic sandstone and shale underlie northern Peninsular Florida and southernmost Georgia; Triassic continental deposits, with diabase sills and dikes, are in grabens under parts of the Georgia coastal plain and northern Florida; and Jurassic terrigenous clastics, carbonates, and evaporites probably are present on the western and southern flanks of the Peninsular arch. Limestone and dolomite comprise most of the Cretaceous and Tertiary section. Anhydrite is abundant in the Lower Cretaceous and Paleocene deposits, and sandstone and shale are present throughout the section in Georgia near the northern edge of the coastal plain. Deposition was in shallow-marine environments on an extensive, slowly subsiding shelf. The southern Appalachians were of low relief and, after Early Cretaceous time, little sediment from this bordering land was transported to the shoreline of the shallow sea. There were, however, several minor marine transgressions and regressions in southern Georgia during the Late Cretaceous and Tertiary, because of changes in the rate of uplift of the bordering land and downwarp of the coastal plain and adjacent marine areas. The regressive eposits, with sands, were deposited slowly, and they were reworked during the succeeding advances of the sea. Many wells have been drilled in nearly all parts of Peninsular Florida and southern Georgia in search for petroleum. Therefore, data are available for deciphering the depositional and tectonic history of the area and assessing its petroleum potential. Only 4 small oil fields, all in southern Florida, have been discovered. Lower Cretaceous carbonates and quartzose sandstones of the continental shelf off western Peninsular Florida, and of the northern flank of the South Florida basin have the greatest petroleum potential. Upper Jurassic carbonates and quartzose sandstones, which are probably present in the South Florida basin and the inner part of the Gulf continental shelf, may have many accumulations, and Paleocene carbonates of northwestern Peninsular Florida and adjacent continental shelf are potentially productive. End_of_Article - Last_Page 1790------------