--> ABSTRACT: Overview of Sedimentation and Sea Level Change in Campanian (Upper Cretaceous) of Northern Margin, Gulf of Mexico, by David T. King, Jr., Michael C. Skotnicki, and Jerry A. Wylie; #91030 (2010)

Datapages, Inc.Print this page

Overview of Sedimentation and Sea Level Change in Campanian (Upper Cretaceous) of Northern Margin, Gulf of Mexico

David T. King, Jr., Michael C. Skotnicki, Jerry A. Wylie

In the outcrop belt and shallow subsurface, the Selma Group (Campanian) of Alabama consists of intergrading marine marl facies and paralic clastic facies. Correlation among 300 surface sections and 40 shallow water wells demonstrates that the Selma facies are arranged cyclically in five discontinuity-bounded packages, three in the Mooreville-Blufftown interval and two in the overlying Demopolis-Cusseta interval. These packages are related to third-order sea level cycles (recurrence interval of approximately 2 m.y.) on the Selma shelf. The packages are similar in that each has an asymmetrical internal facies arrangement and each has a shelfward gradational petrologic sequence comprised of quartzose sands, glauconitic silts, calcareous clays, and marine marls. In addition, ossiliferous sandy event beds in the latter three facies are more abundant near the top of each package; their preservation is an apparent response to higher end-cycle sedimentation rate. The packages differ in their total thickness and apparent extent of shelfward clastic progradation.

Further, the amount of carbonate in the shelf sediments varies widely between and within packages in response to changing paleobathymetry. As a result, chalk beds are developed in the marine marl facies of two cycles and limestone beds are developed in one other cycle.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.