"Arctic Ocean Paleoceanography (ArcOP)": Pilot research and lead of IODP Expedition 377(ArcOP-Pilot)

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In the New Proposal, it has been outlined in detail that the Arctic Ocean was/is a key player in the past, present and future global climate/earth system, however, the marine geoscience research in the Arctic lags behind other world oceans, especially from a paleoclimatic perspective. Concerning the reconstruction of the long-term climate history, a breakthrough in Arctic Ocean paleoclimate research was the first scientific drilling in the permanently ice-covered central Arctic Ocean that was carried out during IODP Exp 302 (ACEX) in 2004. The ACEX results were unprecedented and give important insight into the long-term Arctic climate and sea-ice history on its pathway from Greenhouse to Icehouse conditions. However, major questions related to the climate history of the Arctic Ocean during early Cenozoic times remain unanswered, partly due to the major mid-Cenozoic hiatus (or strongly reduced sedimentation rates) and partly to the poor recovery of the ACEX record. Following-up ACEX and its cutting-edge science, a second scientific drilling on Lomonosov Ridge with a focus on the reconstruction of the continuous and complete Cenozoic Arctic Ocean climate history, has been proposed and is now re-scheduled as IODP Exp 377 (“Arctic Ocean Paleoceanography - ArcOP”) for August-September 2022. In this context, the main focus within this DFG project will be (1) to carry out a pilot study on Polarstern sediment cores recovered at or close to the locations of potential IODP 377 drill sites during Exp PS115/2 in 2018, (2) to contribute to the final planning and implementation as well as the lead of IODP Exp 377 (as one of the co-chief scientists), and (3) to document and present first results of the pilot study as well as the IODP expedition during post-cruise meetings and in reports/publications. The pilot study is of major relevance for IODP Exp 377 as already described in the New Proposal:- By combining the Polarstern cores composed of the uppermost undisturbed about 10 m of late Quaternary sediments, and the IODP drill holes in which the uppermost meters are often not well preserved due to drilling disturbances near the water-sediment interface, a unique complete and undisturbed composite sedimentary section representing the early Cenozoic to Recent, will be obtained.- For correlating the Polarstern cores and IODP sites in detail, MSCL-Logging and XRF scanning data (to be determined on selected Polarstern cores following the IODP rules), will be used.- An age model of the Polarstern cores will be developed based on detailed litho-, cyclo-, paleomagneto-, and 230Th-isotope-stratigraphy to be later incorporated into the age model of the IODP Exp 377 sedimentary sequence.- For reconstructing the Quaternary Arctic climate history, a multiproxy approach will be carried out on the Polarstern cores, including the determination of specific biomarkers, mineral assemblages, coarse-fraction composition, grain-size distributions and XRF scanning data.