Biomarkers and stable isotopic compositions associated with sulfide-rich ancient deposits from mass extinction events

Abstract

This PhD investigates past marine environment affected by ecological crises. Biomarkers and isotopic analyses were conducted in a Devonian-invertebrate and in Early-Triassic samples. Photic zone euxinic conditions and microbial activity are crucial for exceptional biomass preservation. Paradoxically, episodes of free H2S and microbial blooms after the end-Permian extinction, delayed the marine ecosystem recovery. This research has demonstrated organic geochemistry is a powerful tool to improve our understanding of ecosystems evolution and past environmental conditions.