Plio-Pleistocene paleoceanography of the northern and western Pacific

北太平洋和西太平洋的上里奥-更新世古海洋学

• 批准号: RGPIN-2016-06371
• 负责人: Head, Martin
• 金额: $ 2.4万
• 依托单位: Brock University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=684931
• 关键词: Plio; Pleistocene; paleoceanography; northern; western

The NeogeneQuaternary (Pliocene-Pleistocene) transition around 2.8 to 2.45 million years ago represents a fundamental shift in Earth's climate system. The extreme glacial-interglacial oscillations that characterize our more recent climate emerged at this time, although the causes remain uncertain. Deep-ocean sediments offer clues to climate history owing to their continuous and well-dated character, and because the oceans themselves are crucial heat and CO2 sources / sinks as well as being suppliers of moisture for ice sheet growth. Extensive research on North Atlantic sediments has revealed that large ice sheets covered the high northern latitudes around 2.74 and 2.6 million years ago.***While research has focused mostly on the North Atlantic, plausible evidence holds that the northern Pacific Ocean supplied moisture to northern North America allowing the growth of ice sheets 2.74 million years ago. The proposed research targets five deep-sea cores along a transect from the Bering Sea to the South China Sea, and aims to elucidate the Pacific Ocean's role in climate evolution during the NeogeneQuaternary transition. It specifically addresses ice sheet expansion 2.74 and 2.6 million years ago, and explores the associated surface current patterns. It also examines teleconnections between high northern latitude ice sheets and the East Asian winter monsoon system, as reflected in sediments of the marginal Sea of Japan and South China Sea. The intensification of this monsoon is seen in Chinese loess sequences and is driven by cooling in northern Asia. The examination of well-dated ocean sediments may therefore resolve uncertainties in the timing of Chinese loess deposition.***The tools used primarily in the proposed research are the fossilized cysts of dinoflagellates: single-celled microplankton known to be sensitive to environmental change, and as a group tolerant of a wide range in salinities. The cysts (“dinocysts”) are acid-insoluble and resistant to dissolution, and are used as tracers of water masses and indicators of sea-ice extent. Acritarchs, also to be studied, occur in the same preparations as dinocysts but are of unknown biological affinity. They are abundant and relatively diverse in high northern latitudes, and have strong potential for paleoenvironmental analysis over the selected time interval. Dinocysts and acritarchs have been studied extensively in Pliocene and lower Pleistocene deposits of the North Atlantic, but have been largely neglected for the Pacific.***Results will be of particular importance to the paleoclimate and paleoceanography communities, and to climate modelers who test models of future climate against evidence-based paleoclimate reconstructions. The detailed study of dinocysts and acritarchs in tandem with other paleoenvironmental proxies will enhance the utility of this microfossil group for future applications in the Pacific and elsewhere.**

在2.8至245万年前，新苯喹啉季（上新世 - 普遍）过渡是地球气候系统的根本转变。尽管原因仍然不确定，但目前出现了我们最近攀登的极端冰川间 - 冰河振荡，这是我们最近攀登的特征。由于其连续且良好的特征，深海洋沉积物为气候历史提供了线索，并且由于海洋本身是关键的热量和二氧化碳 /水槽，并且是冰盖生长的水分供应商。对北大西洋沉积物的广泛研究表明，大型冰盖覆盖了2.74和260万年前的北纬度。拟议的研究针对从白令海到南中国海的横断面的五个深海核心，并旨在阐明太平洋在新金烯喹啉季过渡期间在气候进化中的作用。它专门解决了2.74和260万年前的冰盖扩展，并探索了相关的表面电流模式。它还研究了高北纬度冰盖与东亚冬季季风系统之间的遥相关，这反映在日本边际海和南中国海的沉积物中。这种季风的强化是在中国的黄土序列中看到的，是由北亚的冷却驱动的。因此，对良好的海洋沉积物的检查可能会在中国黄土沉积的时机中解决不确定性。**** ****拟议的研究中主要使用的工具是鞭毛藻的化石囊肿：已知对环境变化敏感的单细胞微量浮游物，并且作为宽敞的销售范围。囊肿（“ dinocysts”）是酸的抗溶剂，可抵抗溶解，并用作水产的示踪剂和海冰范围的指标。 Acritarchs也是研究的，与恐龙相同的制剂出现，但具有未知的生物学亲和力。它们在高北纬度地区丰富且相对多样，并且在选定的时间间隔内具有很强的古环境分析潜力。在北大西洋的上新世和更新世的沉积物中，对恐龙剂和Acritarchs进行了广泛的研究，但对于太平洋而言。详细的研究与其他古环境代理同时研究了恐龙和杂志，将增强该微化石群在太平洋和其他地方的未来应用。**