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Preservation and Architecture of Transgressive-Regressive Cycles in the Upper Cretaceous John Henry Member of the Straight Cliffs Formation, Left Hand Collet Canyon, Southern Utah, USA

Dooling, Patrick R.*1; Johnson, Cari 1; Allen, Jessica 2
(1) Geology and Geophysics, University of Utah, Salt Lake City, UT.
(2) Chevron, Houston, TX.

The John Henry Member of the Straight Cliffs Formation at Left Hand Collet Canyon is a high accommodation, high sediment supply shoreline that records both transgressive and regressive marginal marine deposits. Left Hand Collet Canyon is located in southern Utah and runs perpendicular to Fifty-Mile Mountain, which mimics the paleoshoreline trending northwest-southeast. Seven measured sections in both strike and dip canyons reveal high resolution features unaccounted for in previous studies of this area. Results from this study show distinct architectures formed via the preservation of transgressive and regressive strata, as well as landward-stepping pinch-outs of the shoreface. Regressive units consist of highly aggradational marine facies and channel facies associations, while transgressive units include lagoonal fill and inlet facies associations. Surfaces bounding transgressive and regressive strata record a process change between tide and wave dominated energies. The overall stacking patterns result in three distinct architectures: lenticular, regressive cycles bounded by flooding surfaces (typical parasequence); wedge-shaped cycles of transgressive and regressive strata (atypical parasequence); and tabular cycles of stacked transgressive deposits. Similar facies architectures are observed at Rogers Canyon, ~20 km southeast along depositional strike of Left Hand Collet Canyon, indicating that these transgressive-regressive cycles are laterally continuous components of the regional marginal marine successions. This study highlights the importance of deposition during transgressive intervals to overall facies stacking geometries. Shorelines with high preservation potential may result in the presence of atypical parasequences not currently predicted in the sequence stratigraphic framework. Recognizing transgressive deposits and their correlation to flooding surfaces is critical to accurate sequence stratigraphic interpretations.


AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California