REVISITING ARCTIC PLEISTOCENE-HOLOCENE (∼2 MA TO PRESENT) FROM ODP 912A: A NEW RECORD FROM THE ARCTIC-ATLANTIC GATEWAY

The Arctic region is one of the most vulnerable areas prone to major sea-level changes in response to global warming. So far, our results from ODP 910C and 911A have provided updated chronology for the Pliocene epoch (5.33–2.58 million years ago). The compiled foraminiferal assemblage (benthic and planktic), stable isotopic analyses, sedimentological and geochemical data (e.g. IP25 record) indicate ice-free conditions in the early Pliocene until sea-ice expanded from the central Arctic Ocean for the first time ca. 4 million years ago. The first large-scale coastline-shelf edge glaciations at ca. 2.75 million years ago was triggered by declining atmospheric CO₂ levels coupled with the North Atlantic warm pool. This provided a regional moisture source along with other feedback mechanisms during the Pliocene.

The current research aims at reconstruction of the climate from a near complete well preserved Pleistocene sequence of ODP 912A from the Yermak Plateau, off NW Spitsbergen. The base of this core is ∼1.95 Ma at 121 mbsf while the Brunhes/Matuyama boundary (∼0.78 Ma) lies at 24.6 mbsf. While ODP 910C and 911A have been revisited for updated chronology of the Pliocene, ODP 912A reveals important events in the Pleistocene (largely missing in ODP 910C) which can be reconstructed through stable isotopic analyses of preserved foraminiferal fauna. The new isotope record (e.g Cassidulina reniforme; C. teretis) will update the published records from ODP 910C to compile a consolidated isotopic record in the high Arctic, the first of its kind done in the area. Therefore it will be crucial to produce this record for future reference on Arctic paleoclimatic archives.