Sequential Structural Restoration of the Lisbon Valley Anticline, Paradox Basin, Utah

Abstract

Salt deposition and subsequent diapiric deformation into salt walls/anticlines occurred in the Paradox Basin associated with the Late Pennsylvanian-Permian uplift of the Uncompahgre contractional fault block (Ancestral Rocky Mountains). Recent workers (Paz Cuellar, Trudgill, Fleming, Hearon, Thompson) have used structural restoration to document the sequential growth of the salt diapirs. Current preservation of stratigraphic horizons upon which to construct restoration datums emphasizes Jurassic and older units. Permian datums (Cutler Group) show that a majority of the diapiric structural relief developed during and immediately following ARM tectonism (Trudgill, 2011). Structural restoration of the Lisbon Valley salt anticline, however, shows a majority of diapiric growth that is younger than Jurassic (Fleming, 2015). In order to capture and visualize the sequential development Cretaceous and Tertiary datums are necessary. This effort requires an estimated reconstruction of sedimentary units lost during Laramide contractional uplift (minor) and Late Tertiary uplift of the Colorado Plateau (major). To that end, I have created a sequential restoration of the Lisbon Valley anticline that includes: 1) a mid-Jurassic datum, 2) a mid-Cretaceous datum, 3) a mid-Eocene datum, 4) an inferred, pre-Colorado Plateau exhumation, Miocene (?) topography, and 5) present-day structural profile beneath current topography. If my stratigraphic reconstructions are correct, a majority of the salt-cored structural relief at Lisbon Valley must have occurred during mid-Tertiary extensional reactive diapirism on the Lisbon Valley normal fault (D_max ~ 1500 m).

AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019