--> Abstract: Successful Simulation of the Shelf to Basin Sediment Cyclicity, Pennsylvanian of the Paradox Basin, Defines Unique Values for Eustasy, Tectonic Movement, and Rates of Sediment Accumulation, by L. Rouch, C. G. St. C. Kendall, P. Moore, and M. L. Patterson; #91012 (1992).

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ABSTRACT: Successful Simulation of the Shelf to Basin Sediment Cyclicity, Pennsylvanian of the Paradox Basin, Defines Unique Values for Eustasy, Tectonic Movement, and Rates of Sediment Accumulation

ROUCH, LINDA, CHRISTOPHER G.ST.C. KENDALL, PHILIP MOORE, and MITCHELL L. PATTERSON, University of South Carolina, Columbia, SC

Computer simulation of depositional sequences requires a choice of appropriate values for subsidence, accumulation rate, and sea level. Although a constant sea level curve can be operative across an entire cross section, both accumulation and subsidence may vary with respect to location. Computer simulations of some cross sections indicate that the ranges of values of these factors are so highly constrained that successful simulations approach a unique solution.

This study used the Paradox basin sea level curve of Goldhammer (1991) to simulate the Paradox Pennsylvanian section. Subsidence rates were varied across the shelf to simulate diverse shelf topography such as intershelf basins and bioherms. Subsidence rates varied within the evaporite basin an order of magnitude higher than published rates for the basin. These differences arise because the current simulation program (SEDPAK) allows variable subsidence rates by location; in other published simulations, rates were held constant for both the shelf and basin. We found shelf subsidence rates of -0.5 m to -0.17 m /1000 yr and basin subsidence rates of -0.4 m to -1.3 m/1000 yr more closely reproduced the parasequence geometries and cycle numbers found in seismic data. The critical constraint on the simulation is the occurrence of shallow water outer shelf bioherms, resulting in fewer shelf cycles and more basin cycles. Simulation runs without bioherms had similar cycle numbers in both the shelf and basin.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)