Ice volume as a trigger for the amplification of Pleistocene millennial-scale climate fluctuations? A terrestrial perspective from Central Asia (Qaidam Basin)

• Applicants: Professor Dr. Oliver Friedrich; Dr. Andreas Koutsodendris
• Subject Area: Palaeontology
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 323912628

Millennial-scale climate fluctuations have increasingly become recognized as a persistent feature of the warmer climates of the latest Pliocene and Early Pleistocene. However, when compared to the well-known millennial-scale fluctuations of the Late Pleistocene, the millennial-scale fluctuations under a warmer climate show markedly lower amplitudes and a lack of correlation to glacial-interglacial changes (i.e., lack of higher amplitudes during glacials compared to interglacials). One hypothesis to explain this difference is an ice-volume threshold that amplifies millennial-scale climate fluctuations and was not reached prior to the Mid-Pleistocene Transition (~1.2-0.7 Ma). The existence of the proposed threshold for the amplification of millennial-scale climate fluctuations and the exact role of northern hemisphere ice sheets as driver mechanisms, however, is still a matter of debate, especially for the intensification of northern hemisphere glaciation (iNHG; ~2.8-2.3 Ma). A solid evaluation of the influence of northern hemisphere ice sheets on the amplification of millennial-scale climate change urgently needs a sophisticated analysis of both marine and terrestrial records. While marine records get more and more available, there is still a lack of terrestrial-based climate records for iNHG. Therefore, it is planned to generate high-resolution (approx. 200 years) sedimentological (grain-size, XRF scanning) and palynological analyses of drill core SG-1b from the Qaidam Basin (NE Tibetan Plateau). The Qaidam Basin is located under the direct influence of the Siberian High, which is in turn directly linked to the amount of ice stored in the northern hemisphere. In addition, core SG-1b provides the opportunity to work at very high resolution and on the basis of maximum stratigraphic precision to answer the questions outlined below. It therefore provides an ideal target to unravel the role of northern hemisphere ice sheets as a trigger for amplitude changes in millennial-scale climate fluctuations. The main objectives of the proposed study are (i) to clarify if there are millennial-scale climate fluctuations of different amplitude in the Qaidam record during the last phase of iNHG (i.e., during MIS 104-94; 2.62-2.38 Ma), (ii) if yes, to figure out if they are related to glacial-interglacial changes, (iii) to clarify if an ice-volume threshold as a trigger for large-amplitude millennial-scale climate fluctuations exist during the early Pleistocene, (iv) to compare the resulting terrestrial data with available results from the marine realm, and (v) to decipher to what extent early Pleistocene glacials are comparable to those from the late Pleistocene.

• DFG Programme: Research Grants