Establishing more accurate chronologies for marine climate records using data from deep-sea cores from northern East China Sea

准确量化地球系统不同方面（深海、海洋表层和大气）变化时间差异的能力，是科学家破译全球冰量、温室气体和太阳日照变率对气候变化的响应的物理基础的关键手段之一。要准确地量化这种变化时间上的差异，需要对深海岩心的气候数据进行精确的年代测定。本项目旨在通过将深海岩心的海洋气候记录与中国葫芦山-三宝洞穴中成熟、高精度的陆地矿床记录（speloethems）进行比较，提高海洋气候记录年龄的准确性。这项研究的结果将使海洋气候记录的年代更加准确，从而为气候模型提供更好的数据，从而提高我们了解过去和未来气候变化的能力。本研究有两个主要目标：1)了解东亚对季风气候变化的强烈敏感性的机制；2)显著提高过去35万年全球底栖三角洲18-O年代学的准确性。第一个目标是与位于日本和韩国之间地区的综合海洋钻探计划（IODP）远征346有关的长期国际合作努力的一部分。合作研究将持续超过本资助计划的两年期限，而第二个目标是本计划的主要重点，并将在拟议的项目期限内完成。在东海北部IODP U1429站点180 m长的3800个样品上测量了浮游有孔虫（gloigerinoides ruber）三角洲18-O和三角洲13-C。这些数据将得到一个约425,000年的时间序列，具有约100年的时间分辨率，能够通过轨道尺度分辨东亚季风系统的百年变化。来自德国基尔大学的合作者将分析同样的3800个底栖有孔虫(Cibicidoides wellerstorfi) δ 18-O和δ 13-C的样本。利用动态规划方法，将盆底三角洲18-O与葫芦岛-三堡岩洞三角洲18-O的放射性定年数据进行比对，将这一高度精确的年龄尺度转化为对底栖海洋记录。这是可能的，因为洞穴和浮游三角洲的18-O记录都是由相同的大尺度季风强迫（温度和降水）驱动的；U1428站点的位置、长度和沉降速率非常适合这项工作

The ability to accurately quantify differences in the timing of change in different aspects of the earth system (deep ocean, surface ocean, and atmosphere) is one of the key means by which scientists are able to decipher the physics underlying climate change in response to variability in global ice volume, greenhouse gasses, and solar insolation. To accurately quantify the differences in this timing of change requires accurate ages for climate data developed from deep-sea cores. This project seeks to improve the accuracy of ages for marine climate records developed from deep-sea cores by comparing these records to well-established, highly-accurate land-based records of mineral deposits (speloethems) in the Hulu-Sanbao cave in China. The results of this research will make ages for marine climate records more accurate, thus providing better data for climate models that enhance our ability to understand climate change, past and future. This proposed work has two main objectives:1) Understanding the mechanisms underlying the strong sensitivity of East Asia to monsoonal climate change2) Significantly increasing the accuracy of the global benthic delta 18-O chronology over the past 350,000 years. The first objective is part of a longer-term international collaborative effort associated with Integrated Ocean Drilling Program (IODP) Expedition 346, located in the region between Japan and Korea. The collaborative research will last beyond the two-year term of this grant proposal, whereas the second objective is the primary focus of this proposal and will be completed in the proposed project duration. Planktonic foraminifer (Globigerinoides ruber) delta 18-O and delta 13-C will be measured on 3800 samples spanning the 180 m length of the IODP Site U1429 in the northern East China Sea. This data will result in a ~425,000 year long time series with ~100 year temporal resolution, capable of resolving centennial through orbital-scale variability in the East Asian monsoon system. Collaborators from the University of Kiel, Germany, will analyze the same 3800 samples for benthic foraminifer (Cibicidoides wuellerstorfi) delta 18-O and delta 13-C. The plantonic delta 18-O will be mapped onto the radiometrically dated Hulu-Sanbao speleothem delta 18-O record using dynamic programming methods, thus transferring this highly accurate age scale into the paired benthic marine record. This is possible because both the cave and planktonic delta 18-O records are driven by the same large-scale monsoonal forcings (temperature and precipitation); the location, length, and sedimentation rates at Site U1428 are uniquely suited to this effort