STABLE ISOTOPIC AND ELEMENTAL GEOCHEMISTRY OF THE ANISIAN PRIDA AND FAVRET FORMATIONS OF NORTHWESTERN NEVADA: INVESTIGATING FACIES VARIATION IN BIOTIC RECOVERY FROM THE END PERMIAN MASS EXTINCTION

Globally, the biotic recovery from the end Permian mass extinction is hypothesized to have been well underway by the Middle Triassic. However, the Middle Triassic of the western United States does not exhibit this recovery equally in all facies. In particular, deeper shelf to basinal settings are relatively fossil-poor with a distinct dearth of benthic forms as compared to shallow water carbonate environments.

In order to better understand the environmental conditions that may have differently affected recovery in different facies, we performed carbon isotopic chemostratigraphy of the Anisian Prida Formation at Fossil Hill and the Favret Formation at Favret Canyon in northwestern Nevada. In addition, we have collected trace and major elemental data via ICP-MS in order to assess the diagenetic history of the samples.

As a whole, the samples collected from Favret Canyon exhibit lower Mn/Sr values than those from Fossil Hill. Samples from Fossil Hill exhibit high Mg/Ca values suggesting extensive dolomitization at that locality. The elemental results combined with preliminary carbon isotopic data will help us construct an onshore-offshore transect to better study dynamics of the Middle Triassic biotic recovery.