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

新提案详细概述了北冰洋在过去、现在和未来全球气候/地球系统中的关键作用，然而，北冰洋的海洋地球科学研究落后于世界其他海洋，特别是从古气候角度。关于重建长期气候历史，北冰洋古气候研究的一项突破是在2004年IODP Exp 302(ACEX)期间，在永久冰覆盖的北冰洋中部进行了第一次科学钻探。ACEX的结果是史无前例的，对北极从温室到冰室条件的长期气候和海冰历史有了重要的洞察。然而，与早新生代北冰洋气候历史有关的主要问题仍未得到解答，部分原因是中新生代主要的间歇期(或沉积速率强烈下降)，部分原因是ACEX记录的恢复较差。作为ACEX及其尖端科学的后续行动，已提议在Lomonosov海脊进行第二次科学钻探，重点是重建连续和完整的新生代北冰洋气候史，现在重新安排在2022年8月至9月进行IODP Exp 377(“北冰洋古海洋学-ArcOP”)。在这方面，DFG项目的主要重点将是：(1)对2018年Exp PS115/2期间在潜在IODP 377钻探地点或附近发现的Polarstein沉积物岩心进行试验性研究；(2)促进IODP Exp 377的最终规划和实施，并(作为联合首席科学家之一)领导IODP Exp 377；(3)在巡航后会议和报告/出版物中记录和介绍试验性研究以及IODP探险的初步结果。初步研究对IODP Exp 377具有重大意义，如新提案中已经描述的：-通过将由最上层的约10米未受干扰的晚第四纪沉积物组成的Polarstein岩心与IODP钻孔相结合，其中最上层的米往往由于水-沉积物界面附近的钻井干扰而没有得到很好的保存，将获得代表早新生代至现代的独特的完整且未受干扰的复合沉积剖面。-为了详细对比Polarstein岩心和IODP地点，MSCL测井和XRF扫描数据(将根据IODP规则在选定的Polarstein岩心上确定)，-将根据详细的岩石、旋回、古地磁和第230度同位素地层学建立Polarstein岩心的年龄模型，稍后将其纳入IODP Exp 377沉积序列的年龄模型。-为了重建北极第四纪气候历史，将对Polarstein岩心进行多代理方法，包括确定特定的生物标志物、矿物组合、粗组分组成、粒度分布和XRF扫描数据。

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.