SR ND ISOTOPIC SIGNATURES OF PALEOCENE EOCENE BOUNDARY FROM ODP SITE 1138A KERGUELEN PLATEAU SOUTHERN OCEAN

Abstract

The boundary between Paleocene and Eocene was characterized by an extreme global warm-up event called Paleocene Eocene Thermal Maximum (PETM) because of the release of huge amounts of carbon into atmosphere and oceans in the form of carbon dioxide and methane due to a combination of varied factors. This resulted in exceptional ocean acidification and devastatingly negative impact on calcifying creatures like foraminifera molluscs and coral (Link I: littp://www.wunderground.com/cliinate/PETM.asp). Biogenic carbonates are fairly resistant to diagenetic alteration and since they are secreted directly from sea water by the organism, they contain no detrital fraction (Dickens, 2005). So the analysis of bulk sediment containing mostly carbonate can be used to determine the contemporary sea water isotopic ratios. It has been observed at few locations (Tibet and Ganga Alluvial Plain) that distribution of 87Sr/86Sr indicate good correlation between climate and Sr-isotopic ratios. Similarly, Nd-isotopic ratios combined with Sr-isotopic ratios give information about the source rocks. Keeping these things in mind, the drill core samples of Paleocene-Eocene age from ODP site II 38A, Kerguelen plateau, Southern Ocean have been analyzed for 87Sr/86Sr and 43Nd/144Nd values across the Paleocene-Eocene boundary. A marked correlation between climate change during PETM and strontium isotopic ratio values has been observed with a distinct regional seawater strontium isotopic ratio profile.