Project Details
Projekt
Pleistocene evolution of eastern Pacific Southern Ocean surface water conditions
Applicant
Dr. Oliver Esper
Subject Area
Geology
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 467394277
Paleoceanographic and -climatic research during the last decade has documented that bio-logical and physical processes occurring in the Southern Ocean and changes in volume and extent of the Antarctic ice sheets play a crucial role in defining and shaping Earth´s climate. A first step to decipher Late Pleistocene eastern Pacific Southern Ocean processes has been done analysing short sediment cores (up to 25-meter-long), reaching back only a few hun-dred thousand years in time. However, our picture of long-term Southern Ocean climate de-velopment is incomplete because only little information is available from the Early and Middle Pleistocene. In the coming years, there will be increasing demand on marine records from the Southern Ocean matching the time span of the new “Oldes Ice” ice core intended to reaching back to 1.5 million years, covering the Mid-Pleistocene Transition (1,250 to 700 thousand years ago). To improve our knowledge on Pleistocene paleoceanographic development in the eastern Pacific Southern Ocean the recovery of three sediment records drilled during IODP Expedition 383 (sites U1539, U1540 and U1541) is an advantage to go further back in time to unravel sea surface processes from the open ocean environments of the Subantarctic Zone. The Subantarctic IODP material will be complimented by one low-resolution POLARSTERN piston core from the Antarctic Zone (PS58/273-1), covering the entire Pleistocene epoch in low resolution. To establish time series of sea surface temperature (SST) variation, sea ice extent and productivity changes, diatom associations will be extracted from the sediments. Diatom counts will be converted quantitatively to summer SST estimates and sea ice concen-tration with recently developed transfer functions. Main aim is to establish high resolution dia-tom records from three Subantarctic central eastern Pacific sites and one Antarctic site to reveal Pleistocene environmental changes. Surface summer temperature reconstructions will be correlated to other temperature proxies reflecting different seasons and water depths. In focus will be the peak interglacials (e.g. Marine Isotope Stages 5 and 11) and especially the super interglacial of Marine Isotope Stage 31. In addition, downcore diatom variation might give information on West Antarctic Ice Sheet Stability via melt water pulses. A further oppor-tunity of diatom analysis will be the refinement of the diatom biostratigraphy, were little is known yet from the Pacific Southern Ocean. Diatom biostratigraphic events will be correlated with magnetostratigraphic events and biostratigraphic events of other microfossils retrieved from the same sediment material to establish an improved stratigraphic framework for the target region.
DFG Programme
Infrastructure Priority Programmes
International Connection
New Zealand, United Kingdom
Cooperation Partners
Dr. Christina Riesselman; Dr. Pilar Mariem Saavedra-Pellitero
