--> Abstract: Controls on Accommodation in Retroarc Foreland Systems: Case Study of The Lea Park Formation And Equivalents, Western Canada S; #90063 (2007)

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Controls on Accommodation in Retroarc Foreland Systems: Case Study of The Lea Park Formation And Equivalents, Western Canada Sedimentary Basin

 

Mumpy, Andrew J.1, Octavian Catuneanu1 (1) University of Alberta, Edmonton, AB

 

The Lea Park Formation of the Western Canada Sedimentary Basin (WCSB) is a westward-thinning, regionally extensive succession of marine sediments deposited in the Western Interior Seaway during transgressive and regressive phases of the Campanian Claggett Cycle. The WCSB is a retroarc foreland system produced by thrust sheet loading in the Canadian Cordillera and resultant flexural displacement of the lithosphere east of the orogenic front. Relative sea level fluctuations produced by flexural subsidence and uplift are the primary control on the creation or destruction of accommodation space in foreland settings, and thus control the thicknesses of depositional sequences to a large extent. Ranges of thickness values from various locations across the WCSB were compiled for a chronostratigraphic interval encompassing the Lea Park and equivalents (~76 Ma-84 Ma). Simple calculations suggest that thicknesses of sediment accumulations in the forebulge and backbulge depozones of the WCSB exceed the predictions of widely accepted flexural models. We investigate the relative contributions of additional subsidence mechanisms including: eustatic fluctuation, dynamic loading, and basement tectonism.

 

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