Collaborative Research: Evolution of the deep South Atlantic since the last interglacial period inferred from a depth transect of Cape Basin sediment cores

有相当多的证据表明，深海在控制更新世冰期和间冰期的演化中发挥了一定的作用。然而，经过几十年的研究，沉积示踪剂在多大程度上能够区分冰河时代海洋和现代海洋之间的深海循环差异，仍然存在争议。这一合作项目将调查过去海洋环流的变化，办法是利用纳米比亚边缘和开普敦盆地一条深度断面上的岩芯，为上一次冰川-间冰期循环中的八个时间片生成若干常见古海洋学示踪剂(包括底栖生物d18O和d13C、放射性碳、Cd/Ca、锌/钙和B/Ca)的多代理记录。这些时间片段将代表从间冰期状态演化到整个冰川周期的步骤。这项研究将围绕大西洋水团演化、环流和碳循环之间的联系、保守和非保守指标之间的差异以及不同于海洋混合效应的主要边界条件变化的可能性等一系列问题展开。更广泛的影响：该项目将提供世界海洋的两个主要深水团在整个冰循环中混合的详细图景，这将对海洋学家和气候学家具有广泛的用途。资助将支持两名博士生，并提供代理数据收集和解释方面的重要经验。该项目还将作为夏季REU研究员的平台，并为几名本科生学习研究和实验室技术提供支持。此外，资金将有助于通过德克萨斯农工大学的地球深部学院开发一门关于地球深层循环的课程。

There is considerable evidence that the deep ocean plays some role in governing the evolution of Pleistocene ice ages and interglacial periods. Yet after several decades of research, there is still debate over the degree to which sedimentary tracers can distinguish differences in deep ocean circulation between ice age oceans and the modern ocean. This collaborative project will investigate past ocean circulation changes by generating multi-proxy records for several common paleoceanographic tracers (including benthic d18O and d13C, radiocarbon, Cd/Ca, Zn/Ca and B/Ca) for eight time slices over the last glacial-interglacial cycle using cores along a depth transect from the Namibian margin and Cape Basin. These time slices would represent the step in evolution from interglacial state through a full glacial cycle. The research will focus around a series of questions concerning water mass evolution in the Atlantic Ocean, the connection between circulation and carbon cycling, differences between conservative and non-conservative proxies, and the possibility for major boundary condition changes distinct from ocean mixing effects. Broader impacts:This project will provide a detailed picture of the mixing between the two principal deep water masses of the world's ocean across a full ice cycle, which will be of widespread use to oceanographers and climate scientists. Funding will support two Ph.D. students and provide significant experience in proxy data collection and interpretation. The project will also serve as a platform for a summer REU fellow and provide support for several undergraduate students to learn research and laboratory techniques. Additionally, funding will help develop a lesson on deep earth circulation through the Deep Earth Academy at Texas A&M University.