Deccan Volcanism: a main trigger of environmental changes leading to the K/Pg mass extinction?

Abstract

Recent studies indicate that the bulk (80%) of Deccan trap eruptions occurred over a relatively short time interval in magnetic polarity C29r, whereas multi-proxy studies from central and southeastern India place the Cretaceous-Paleogene (K/Pg) mass extinction near the end of this main phase of Deccan volcanism suggesting a cause-and-effect relationship. Beyond India multi-proxy studies also place the main Deccan phase in the uppermost Maastrichtian C29r below the K/Pg (planktic foraminiferal zones CF2-CF1), as indicated by a rapid shift in ¹⁸⁷Os/¹⁸⁸Os ratios in deep-sea sections from the Atlantic, Pacific and Indian Oceans, coincident with rapid climate warming, coeval increase in weathering, a significant decrease in bulk carbonate indicative of acidification due to volcanic SO2, and major biotic stress conditions expressed in species dwarfing and decreased abundance in calcareous microfossils (planktic foraminifera and nannofossils).