FALL FIELD TRIP, Saturday & Sunday, Oct. 26–27, 2019
Anatomy of Anachronistic Carbonate Platform: Environmental Conditions and Biotic Recovery in the Aftermath of the Permian – Triassic Mass Extinction
Adam D. Woods, Rostislav Kovtun California State University, Fullerton
Check out this video courtesy of Scott Hector!
The 2019 PS-SEPM Fall Field trip examined Lower Triassic carbonates of the Union Wash Formation in the southern Inyo Mountains in order to examine environmental conditions in a shallow to deep carbonate sequence deposited in the aftermath of the Permian – Triassic mass extinction. We started at the classic angular unconformity in Darwin Canyon that separates Lower Permian and Lower Triassic rocks. From there, we walked through the majority of the section exposed in the Darwin Hills. We examined abundant Thalassinoides burrow networks that are found within shallow water sediments of the lower member, and represent an early, nascent recovery. Unusual fabrics and facies of the middle and upper member that are indicative of harsh environmental conditions made up the rest of our day, including seafloor precipitates, thick sequences of cm-scale alternations of laminated micritic limestone and calcareous siltstone, and unusual micritic limestone units. We also got a chance to see ample evidence of soft sediment deformation. Sunday we examined microbial facies and fabrics found in the upper member of the Union Wash Formation at Cerro Gordo, CA.