Mercury stratigraphy of early Danian sediments from the Rio Grande Rise and the timing of Deccan volcanism

Abstract

The Maastrichtian - Danian transition is characterized by one of the largest mass extinctions recorded in the geological history of Earth, the Cretaceous-Paleogene (K-Pg boundary). Chemostratigraphic indicators (e.g. Mercury) are of fundamental importance for understanding the causes of this extinction and its effects on the environment in which life after the K-Pg boundary flourished. This study presents a new mercury (Hg) concentrations and Hg/TOC dataset for Deep Sea Drilling Project (DSDP) Site 516F (Rio Grande Rise), in the framework of carbon cycle proxies that depict the Dan-C2 event within the ∼500 kyr that followed the K-Pg event, from 66.05 to 65.55 Ma, and their temporal relationship with the Deccan Traps (DT) volcanic event. Enriched Hg and Hg/TOC values were observed between ∼65.89 Ma (963.45 mbsf) and 65.98 Ma (963.73 mbsf), ∼60 kyr before (or 40 cm below) the Dan-C2 event. Furthermore, the stratigraphic position with the highest Hg and/or Hg/TOC values is ∼40 kyr after the K-Pg boundary. Our results suggest that the DT volcanism is unrelated with the Dan-C2 event observed at Site 516, and that the highest Hg/TOC appear to be coeval with the eruption of the Deccan Ambenali Formation lavas at about ∼65.90–65.95 Ma.