Implications of the infra- and inter-trappean biota from the Deccan, India, for the role of volcanism in Cretaceous-Tertiary boundary extinctions

Abstract

The fossil record shows a remarkable similarity between the biota that existed before and after the initiation of Deccan volcanic activity. Virtually all the available palaeontological evidence, such as the fauna and flora of the freshwater infra- and inter-trappean beds and the planktonic foraminifera from the subsurface infra- and inter-trappean beds of the southeastern coast, do not favour the initiation of Deccan volcanism as the cause of mass extinctions at the Cretaceous-Tertiary (K-T) boundary. Instead, a combination of events, such as an extended period of volcanism, changes in sea-level and related climatic changes, and certain local factors, may have played a significant role in selectively eliminating various groups of organisms. This view is further reinforced by the biotic changes across the K-T iridium layer in the Um Sohryngkew River section of Meghalaya, northeastern India.