Short-term waxing and waning of Antarctic ice sheets during the late Oligocene
ACRONYM
Oligocene Antarct
Title
Short-term waxing and waning of Antarctic ice sheets during the late Oligocene
General information
Available sea-level reconstructions for magnetochron C8n.2n from North Atlantic Site U1406 show a highly dynamic Antarctic ice sheet characterized by obliquity-controlled high-amplitude fluctuations of up to 60% relative to modern ice volume. Furthermore, the available record suggests a decrease in Antarctic ice volume from a size comparable to today to an ice-free Antarctic between 26 and 25.3 Ma. Since these ice-volume reconstructions are the only high-resolution record yet available and show large differences to published studies that suggest a relatively large and stable Antarctic ice sheet across the study interval, it is planned to critically test the available sea-level/ice-volume reconstructions from the North Atlantic. Furthermore, a mechanistic understanding of the processes that led to the ice-sheet dynamics observed for the late Oligocene will be obtain. These objectives will be reached through the generation of paleoclimate proxy records for a specific time interval of the late Oligocene (magnetochron C8n.2n; 25.32–25.98 Ma) to allow to work on highest stratigraphic precision. Proxy records to be generated are driven by two independent approaches to have a sensitive test of the available sea-level/ice-volume reconstructions; (i) based on benthic fora¬mini¬fe¬ral geochemistry (Mg/Ca and stable isotopes) and (ii) Nd isotopes from the detrital fraction of bulk-sediment samples. Providing this information will allow detailed insight into the evolution of the cryosphere for a critical interval of Cenozoic climate evolution (i.e., the Oligocene rise of the icehouse climate). Moreover, the data will allow a sophisticated comparison of the driving mechanisms behind G/IG cycles during two fundamentally different intervals of Earth’s history with respect to their climatic processes: the unipolar-glaciated Oligocene and the bipolar-glaciated Late Pleistocene.
Start
December, 2019
End
November, 2021
Funding (total)
4000
Funding (GEOMAR)
-
Funding body / Programme
-
DFG
/
Coordination
Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Germany
Contact
Partners
University Heidelberg, Germany
