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Title: Norphlet formation (Upper Jurassic) of southwestern and offshore Alabama: environments of deposition and petroleum geology

Journal Article · · Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:5237337

Upper Jurassic Norphlet sediments in southwestern and offshore Alabama accumulated under arid climatic conditions. The Appalachian Mountains of the eastern United States extended into southwestern Alabama to provide a barrier for air and water circulation during the deposition of the Norphlet Formation. These mountains produced topographic conditions that contributed to the arid climate, and they affected sedimentation. Norphlet paleogeography in southwestern Alabama was dominated by a broad desert plain, rimmed to the north and east by the Appalachians and to the south by a developing shallow sea. The desert plain extended westward into eastern and central Mississippi. Norphlet hydrocarbon potential in southwestern and offshore Alabama is excellent; six oil and gas fields already have been established. Petroleum traps discovered to date are primarily structural traps involving salt anticlines, faulted salt anticlines, and extensional fault traps associated with salt movement. Reservoir rocks consist primarily of quartz-rich sandstones that are eolian, wadi, and marine in origin. Porosity is principally secondary (dissolution) with some intergranular porosity. Smackover algal carbonate mudstones were probably the source for the Norphlet hydrocarbons. Jurassic oil generation and migration probably were initiated in the Early Cretaceous.

Research Organization:
Geological Survey of Alabama and University of Alabama, University Station, Tuscaloosa, Alabama
OSTI ID:
5237337
Journal Information:
Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 69:6
Country of Publication:
United States
Language:
English