--> Abstract: Sedimentation as the Result of Interplay of Tectonics and Sea Level Change: Evidence from Pennsylvanian to Early Permian Tensl; #90063 (2007)

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Sedimentation as the Result of Interplay of Tectonics and Sea Level Change: Evidence from Pennsylvanian to Early Permian Tensleep Sandstone in Wyoming

 

Zhang, Qingsheng1, Dag Nummedal2 (1) Parallel Data Systems, Stafford, TX (2) Colorado School of Mines, Golden, CO

 

Two geological conditions controlled the sedimentation of the Pennsylvanian to Early Permian Tensleep Sandstone: the uplift of Ancestral Rocky Mountains due to the collision between the North American Plate and Gondwana Continent, and the high-frequency and high-amplitude sea level change due to the glaciation in the southern hemisphere. Outcrop studies at the Middle Fork of the Powder River and Fremont Canyons, and core and well log study at the Teapot Dome, indicate the Tensleep Sandstone represents an overall forestepping mega-sequence caused by the uplift of Ancestral Rocky Mountains. The mega-sequence, which was influenced by numerous marine transgressions caused by the high-frequency and high-amplitude sea level change, contains multiple sequences. A typical sequence in the Tensleep Sandstone contains a lowstand eolian sand dune, interdune or sand sheet facies, a transgressive coastal sabkha, interdune or shoreface facies, a high stand epeiric marine carbonate facies and a sequence boundary at the top. The sequence boundaries can be recognized with erosional surfaces, paleosol, facies change, conglomerates, karst, carbonate breccia and gamma ray intensity change. Correlation indicates that six basal sequences onlap from the Middle Fork of the Powder River to the Fremont Canyon, reflecting the presence of the Pathfinder Uplift to the south during Tensleep deposition period. This study provides an example to show that the development of sequences and sequence boundaries in the Tensleep Sandstone which was deposited in a stable and flat shelf environment is the result of the interplay of tectonics and sea level change.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California