Collaborative Research: Understanding the Southern Ocean's Contribution to Cenozoic Deep-Water Circulation

合作研究：了解南大洋对新生代深水环流的贡献

基本信息

批准号：
1737366
负责人：
Niall Slowey
金额：
$ 59.6万
依托单位：
Texas A&M University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-15 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1737366&HistoricalAwards=false
关键词：
Collaborative Research Understanding Southern Ocean

项目摘要

Ocean circulation plays an important role in the transport of heat around the planet and the cycling of carbon and nutrients in the ocean, directly affecting life and climate. This project aims to better understand the histories of two of the largest and most important sets of deep ocean currents. Ocean water masses that originate from both the Southern Ocean and North Atlantic Ocean intersect the continental margin of Argentina and records of how the circulation of these waters changed over time are preserved by the marine sediments that accumulate along this margin. An integrated program of seismic imaging, seafloor sediment sampling, and seawater property measurements will be used to investigate the southern Argentine margin and its sedimentary records of past ocean circulation. Seismic techniques will be used to image the surface of the seafloor and the underlying sediments down to 1 km. This imaging will enable better understanding of the large-scale oceanographic/geological processes that affected the margin over the Cenozoic (the past 65 million years). Sediment cores along with ocean water property data will be collected from a range of water depths to reconstruct the temporal evolution of the compositions and geometries of the water masses during the late Pleistocene. The seismic survey will also provide the requisite information to locate sites for future scientific drilling programs. The project includes student training, public education through museum exhibits, and at-sea activities potentially including a teacher-at-sea. The field component will provide opportunities to train graduate students in professionally relevant data acquisition and interpretation techniques.The Southern Ocean is the engine for today's deep- to intermediate-water circulation, supplying about half of the energy for deep ocean mixing; yet, most understanding of late Pleistocene thermohaline circulation changes derives from the North Atlantic. Understanding of the role of Southern Ocean water masses is limited by a paucity of deep-sea sedimentary records of these water masses. Sediments deposited along the continental slope of the Argentine margin offer a unique opportunity to reconstruct comprehensive histories of Southern Ocean sourced intermediate and deep waters close to their origin, and to better understand their fundamental connections to global ocean circulation and climate during the late Pleistocene. During a 43-day oceanographic cruise to the margin, the research team will collect seismic data (multibeam-mapping, high-resolution subbottom profiling, and multichannel seismic surveying) and sediment cores (multicores and piston cores) from water depths of ~500 to ~5000 meters, a range that spans the depths where all major intermediate and deep waters in the South Atlantic occur today. Ship- and shore-based analyses of a broad suite of physical and geochemical proxies will allow the researchers to reconstruct the temporal evolution of the compositions and geometries of the water masses during the late Pleistocene. The seismic and sediment data combined will enable better understanding of the nature of the sediments that comprise the southern Argentine margin and the oceanographic/geological processes that influenced the margin during both the late Pleistocene and the Cenozoic. The latter will provide a broad regional and temporal context to better understand the interaction between sediments and bottom currents that can be further exploited with scientific ocean drilling; moreover, the multichannel seismic data will be used to situate proposed drilling sites.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

海洋循环在地球周围的热量运输以及海洋中碳和养分的循环中起着重要作用，直接影响生命和气候。该项目旨在更好地了解两种最大，最重要的深洋流的历史。源自南部海洋和北大西洋的海水质量与阿根廷的大陆边缘相交，并记录了这些水的循环随时间变化如何由沿着这个边缘积累的海洋沉积物保存。地震成像，海底沉积物采样和海水性能测量的综合计划将用于研究阿根廷南部的边缘及其过去海洋循环的沉积记录。地震技术将用于成像海底的表面和下面的沉积物至1 km。这种成像将使人们能够更好地了解影响库综合的大型海洋学/地质过程（过去6500万年）。将从一系列水深收集沉积物核心以及海水性能数据，以重建晚期更新世晚期水质量的成分和几何形状的时间演化。地震调查还将提供必要的信息，以找到未来的科学钻探计划的站点。该项目包括学生培训，通过博物馆展览的公共教育以及潜在的AT-SEA活动，包括教师。该领域的组成部分将为培训研究生提供专业相关的数据获取和解释技术的机会。南大洋是当今深水至中等水流通的引擎，为深海混合提供了大约一半的能量；然而，对晚更新世热盐循环变化的大多数理解来自北大西洋。了解南洋水质量的作用受到这些水质量深海沉积记录的限制。沿阿根廷边缘的大陆斜率沉积的沉积物为重建南部海洋的全面历史提供了独特的机会，该历史是靠近其起源的中间和深水，并更好地了解他们在晚期更新世期间与全球海洋循环和气候的基本联系。在为期43天的海洋学巡游中，研究团队将收集地震数据（多束映射，高分辨率的子琴盘分析和多通道地震测量）和沉积物岩心（多层和活塞岩心），从〜500至〜5000米的水深，跨越了当今的范围。基于船舶和海岸的一系列物理和地球化学代理的分析将使研究人员能够重建晚期更新世期间水质量的成分和几何形状的时间演变。地震和沉积物数据的结合将使您可以更好地理解构成阿根廷南部边缘的沉积物的性质以及在晚期更新世和新生代期间影响边缘的海洋学/地质过程。后者将提供广泛的区域和时间环境，以更好地了解沉积物和底电流之间的相互作用，可以通过科学的海洋钻孔进一步利用这些相互作用。此外，多通道地震数据将用于位置拟议的钻井场所。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准来通过评估来支持的。