Paleoclimate evolution of the NW-Pacific over the past 25Ma

过去25Ma西北太平洋古气候演变

• 批准号: 261494927
• 负责人: Professor Dr. Thorsten Bauersachs
• 金额: --
• 依托单位: Arbeitsgruppe Organische Geochemie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/261494927?language=en
• 关键词: Paleoclimate; evolution; NW; Pacific; over

The subtropical Kuroshio Current (KC) is an important western boundary current of the Northwest (NW) Pacific Ocean, which transports warm and saline water masses from the Western Pacific Warm Pool to northern mid-latitudes. At present the KC and the polar Oyashio Current (OC) converge at ~36°N off Japan, but the KC-OC interfrontal zone is known to have shifted to more southerly latitudes during glacial periods, thereby allowing the OC to transport cold surface water masses to more southerly latitudes. Therefore, the interplay of both ocean currents plays an important role in the meridional advection of moisture and heat to northern latitudes and exerts a major control on the climate and terrestrial evolution of the NW Pacific and the East Asian continent. The aim of this study is to establish deep-time high-resolution records of sea surface temperature (SST) and terrestrial vegetation change in order to study the paleoceanography and paleoclimate evolution of the NW Pacific and associated shifts in terrestrial floral communities from the early Miocene to the present. For this, deep-sea sediments recovered at Sites C0011/C0012 during IODP Expeditions 322 and 333 as well as Site U1437, which was drilled during IODP Expedition 350, are currently investigated using bulk-geochemical and lipid biomarker techniques. Extraction of sediments from Sites C0011/C0012 yielded a continuous record of SST change off the coast of Japan over the last 14.3 Ma using the TEXH86, UK´37 and LDI lipid paleothermometers. Although absolute SST values for the different proxies vary in magnitude, all three records show a long-term cooling trend from the late Miocene to the present with temperatures decreasing by some 5-10 °C. At Site U1437, a sedimentary sequence spanning a time interval from the early Miocene to Holocene was drilled with excellent core recovery. Preliminary lipid biomarker data indicates that the application of organic temperature proxies is feasible at Site U1437 with TEXH86 and LDI-based SST records showing similar trends as observed for Sites C0011/C0012. Difference in absolute temperatures may, however, provide valuable information on the meander flow pattern of the KC and thus on the meridional transport of heat to northern mid-latitudes. In the framework of the 2nd phase of the project, we plan to extend our existing records of paleoclimate and paleoceanographic change in the NW Pacific to the early Miocene and study the variability and strength of the OC by including deep-sea sediments recovered from Site 436 during DSDP Expedition 56 in our lipid biomarker analysis. The final synthesis of our data will allow reconstructing the paleoclimate and paleoceanographic evolution of the NW Pacific in an unprecedented spatiotemporal resolution and will provide the first deep-time record of SST change from the NW Pacific that dates back to the early Miocene (~25 Ma BP).

亚热带黑果岛电流（KC）是西北太平洋（NW）太平洋的重要西部边界电流，该电流将温暖和盐水从西太平洋温暖的池运送到北部中部纬度。目前，KC和Polar Oyashio电流（OC）在日本附近约36°N，但已知KC-OC额叶区域已在冰川期间转移到更南的纬度，从而允许OC将冷地面水质量运输到更南方的纬度。因此，两种洋流的相互作用在水分和热量的子午冒险中都起着重要作用，并对西北太平洋和东亚大陆的气候和陆地演变产生了重大控制。这项研究的目的是建立海面温度（SST）和陆地蔬菜变化的深度高分辨率记录，以研究西北太平洋地区的古摩纳山学和古气候演化，以及从中新世早期到现在的陆地花卉群落的相关变化。为此，目前使用Bulk-Geochemical and Lipid BioMarker Techniques研究了IODP Expeditions 322和333期间在IODP Expeditions 322和333的地点回收的深海沉积物。使用TEXH86，UK´37和LDI脂质的浅热热计，在过去的14.3 MA中，从日本海岸提取沉积物C0011/C0012在日本海岸的连续记录中。尽管不同代理的绝对SST值在幅度上有所不同，但所有三个记录均显示了从中新世晚期到演示的长期冷却趋势，温度降低了约5-10°C。在U1437现场，钻出从中新世早期到全新世的时间间隔的沉积序列，并具有出色的核心恢复。初步脂质生物标志物数据表明，在U1437中，有机温度代理的应用是可行的，基于TEXH86和基于LDI的SST记录显示出与位点C0011/C0012相似的趋势。但是，绝对温度的差异可能会提供有关KC蜿蜒流模式的有价值的信息，从而提供了将热量转移到北部纬度的子午线运输。在项目的第二阶段的框架内，我们计划将我们现有的NW Pacific的古气候和古介电变化记录扩展到中新世早期，并通过在我们的Lipid BioMarker分析中包括从DSDP Excessition 56期间从地点436中回收的深海沉积物来研究OC的可变性和强度。我们数据的最终综合将允许在前所未有的时空分辨率中重建NW Pacific的古气候和古代志能力演化，并将提供从NW Pacific的首个SST变化的深度记录，该记录可追溯到早期的中新世早期（〜25 MA BP）。

项目成果

Impact of climate change on the magnetic mineral assemblage in marine sediments from Izu rear arc, NW Pacific Ocean, over the last 1 Myr

• DOI: 10.1016/j.palaeo.2017.05.016
• 发表时间: 2017-08-15
• 期刊: PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
• 影响因子: 3
• 作者: Kars, Myriam;Musgrave, Robert J.;Bauersachs, Thorsten
• 通讯作者: Bauersachs, Thorsten

Magnetic Mineral Diagenesis in a High Temperature and Deep Methanic Zone in Izu Rear Arc Marine Sediments, Northwest Pacific Ocean

• DOI: 10.1029/2018jb015861
• 发表时间: 2018-10
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: M. Kars;R. Musgrave;T. Hoshino;A. Jonas;T. Bauersachs;F. Inagaki;K. Kodama

Late Quaternary water temperature variations of the Northwest Pacific based on the lipid paleothermometers TEX H 86 , U Ḱ 37 and LDI

• DOI: 10.1016/j.dsr.2017.04.018
• 发表时间: 2017-07
• 作者: A. Jonas;L. Schwark;T. Bauersachs