--> Abstract: Mississippian Carbonate-Shelf Margins, Western United States, by Peter R. Rose; #90968 (1977).

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Abstract: Mississippian Carbonate-Shelf Margins, Western United States

Peter R. Rose

Regional linear carbonate-shelf margins, or stratigraphic reefs, are postulated to have developed during Mississippian time along the eastern flank of the Cordilleran miogeosyncline in the western United States. These shelf margins are analogous to well-documented ancient and modern geologic counterparts, such as the Guadalupian reef of the West Texas Permian basin, the Early Cretaceous Edwards shelf margin of the Gulf Coast, and the modern Florida reef tract. Two Mississippian shelf margins are believed to have been present. The lower one, equivalent to the Madison Limestone, developed as an integral part of a widespread carbonate depositional complex of Kinderhook through early Meramec age. The upper shelf margin developed west of the earlier stratigraphic reef as part of a regional carbonate depositional complex of middle Meramec to late Chester age. Evidence for both shelf margins consists of (1) a linear physical barrier; (2) restricted sediments in the shelf interior; (3) abrupt basinward thinning of sediments and basin starvation just seaward of the shelf edge; (4) profound facies changes coincident with the basinward thinning--from light-colored, skeletal, shelf-carbonate rocks to dark, fine-grained, silty, basinal carbonate rocks; and (5) the consistent regional presence of the first four patterns Seaward topographic relief along the front edge of the lower shelf margin was probably about 200 to 400 m, and maximum relief along the central sector of the upper shelf margin may have approached 1,000 m. Recognition of these stratigraphic relations bears directly on prediction of reservoir quality, source-rock distribution, and presence of mineralized host rocks.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC