Subsurface Characterization and Sequence Stratigraphy of the Mississippian Pride Mountain/Hartselle Clastic Tongue, Bangor Limestone Carbonate Ramp, and Neal Black Shale in the Black Warrior Foreland Basin, Alabama and Mississippi
Carrie A. Kidd
University of Kentucky, Lexington, KY
A depositional framework is constructed for the Mississippian (Chesterian) Pride Mountain Formation and Hartselle Sandstone clastic tongue, the lower Bangor Limestone carbonate ramp, and the Neal black shale in the Black Warrior basin, Alabama and Mississippi. The Lowndes-Pickens synsedimentary fault block controlled sediment dispersal in the Pride Mountain/Hartselle clastic tongue in the southern part of the basin. The Pearce siltstone, a previously unnamed unit identified only in the subsurface, was deposited in a restricted environment bounded by the Lowndes-Pickens block and the Hartselle Sandstone. Approximately 250 geophysical well logs, 15 well cuttings descriptions, and outcrop data support construction of cross sections, isopach maps, and transgressive-regressive sequence stratigraphy interpretation.
The Pride Mountain, Hartselle, and lower Bangor interval contains one complete and one partial transgressive-regressive stratigraphic sequence. The Pride Mountain and Hartselle contain four progradational sandstone parasequences. A possible exposure surface at the top of the Hartselle and Monteagle Limestone is interpreted as a maximum regressive surface and separates the underlying Pride Mountain/Hartselle/Monteagle regressive systems tract from an overlying transgressive systems tract composed of shale and limestone. The lower Bangor carbonate ramp is laterally continuous and highly cyclic in the upper ramp and grades from oolitic shoals southwestward into a condensed section, the Neal black shale, at the toe of the ramp. The lower Bangor contains six to seven basin-wide coarsening-upward parasequences capped by flooding surfaces.
AAPG Search and Discover Article #90087 © 2008 AAPG/SEG Student Expo, Houston, Texas