New Stratigraphic Constraints on Spatio-Temporal Structural Evolution in the Uinta, Piceance and Denver Basins

Abstract

Detailed, regional sequence-stratigraphic correlation and growth-strata analysis support a complex spatio-temporal overlap in structural style during the Sevier-Laramide transition, and a general NE-younging trend in Laramide uplifts that mirror Shatsky Rise subduction. In the western margin of the Uinta basin, Cenomanian- Turonian syntectonic unconformities in the Sanpete Fm., and locally-shoaling shoreface lithofacies in the lower Funk Valley Fm. indicate incipient, thrust-propagation folding in Thistle, UT at ~95–92 Ma. These structures later formed part of the Santaquin Culmination at ~85–80 Ma, pinning the margin of the Sevier Fold-thrust belt in Central Utah. In the south-central Uinta Basin, Campanian intrabasinal stratal thinning and syntectonic unconformity development in the Mesaverde Grp indicates Laramide-style uplift of the San Rafael Swell at ~77–80 Ma. In the northeastern and northwestern parts of Uinta Basin, Campanian thinning trends outline two sites of incipient topography associated with Uinta Uplift at ~75 Ma. The 2 Campanian structures linked laterally forming the Uinta Uplift in the late Campanian to early Maastrichtian; this is consistent with a well-formed, East-West trending, stratal thick that parallels the southern boundary of the Uinta Uplift at ~73 Ma. At the Uinta-Piceance Basin boundary a thinning trend in the lower Williams Fork Fm. (~73 Ma) followed by stratal truncation and growth-strata development in the upper Williams Fork Fm. (~72 Ma) across the Douglas Creek Arch, indicates Campanian-Maastrichtian aged Laramide-style uplift in the Piceance Basin. In the Denver Basin, syntectonic unconformities in the Denver-Dawson formations indicate early Paleocene (~67 Ma) uplift of the south-central Colorado Front Range.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015