Isotope and trace element geochemistry of Eocene and Oligocene foraminifers from Site 748, Kerguelen Plateau

Stable carbon and oxygen isotope analyses were conducted on well-preserved planktonic and benthic foraminifers from a continuous middle Eocene to Oligocene sequence at ODP Site 748 on the Kerguelen Plateau. Site 748 oxygen isotope and paleontological records suggest that southern Indian Ocean surface and intermediate waters underwent significant cooling from the early to late Eocene. The rapid 1.2‰ oxygen isotope increase recorded by benthic foraminifers just above the Eocene/Oligocene boundary represents the ubiquitous early Oligocene δ¹⁸O event. The shift here is unique, however, as it coincided with the sudden appearance of the ice-rafted debris (IRD), providing the first direct link between Antarctic glacial activity and the earliest Oligocene δ¹⁸O increase. -from Authors