Collaborative Research: Linking Marine and Terrestrial Sedimentary Evidence for Plio-pleistocene Variability of Weddell Embayment and Antarctic Peninsula Glaciation

南极冰盖和冰川的融化和崩溃可能导致未来海平面上升，这一点令人担忧。我们可以通过研究冰盖在过去气候中的表现，特别是在类似或比现在更温暖的条件下，来提高我们对南极冰盖和海洋之间水交换的理解。在这个项目中，研究小组将通过结合南极半岛附近冰川变化的海洋和陆地证据，记录地球从温暖的上新世过渡到更新世冰期的整个时间间隔南极洲的反应，并辅以关于环境变化的时间尺度和化石证据的详细工作。一个重要的目标是测试南极洲的冰川是否与北方半球的冰川同时变化，因为地球最近的冰河时代加剧，或者对南半球的区域气候强迫做出反应。来自七个美国机构的11名调查人员以及阿根廷合作者将研究国际海洋发现计划的新沉积物岩心，以及该计划的遗留岩心和詹姆斯罗斯岛的陆地露头。该集团拥抱一个垂直整合的研究计划，允许高中，本科，研究生，博士后和教师在同一项目上合作。这种结构充分利用了近同行指导和强大的协作研究网络的发展的好处，同时允许所有参与者拥有项目不同部分的所有权。该团队的所有成员都坚定地致力于吸引来自代表性不足的群体的研究人员，并将通过现有渠道以及通过共同创建节目来实现这一目标，该节目将不同学生的观点集中在关于海平面上升和气候变化的对话中。拟议的研究旨在了解北方和南半球冰川与气候变化之间的阶段性，作为了解驱动因素和遥相关性的一种手段。过去的南极冰川作用的动力学可以研究使用独特的同位素地球化学和矿物指纹冰川部门绑在一个约束良好的时间模型的地层序列。拟议的工作将通过耦合生物地层学和磁性地层学工作进一步完善地层背景。冰山崩解的规模和冰山的路径将使用流量，地球化学和矿物学特征，以及冰筏碎屑的40 Ar/39 Ar和U-Pb年代学来揭示。这些来源示踪剂将确定南极洲冰盖的哪些部分更容易崩溃，这些事件的时间和速度将通过它们的地层环境来揭示。此外，该团队将与阿根廷合作者合作，通过研究詹姆斯罗斯岛上火山流动的冰川记录，将海洋和陆地记录联系起来。这些新的限制将与最先进的冰盖模型相结合，将冰动力学的变化与其根本原因联系起来。总之，这些严格的地层约束，地球化学特征和冰盖模型模拟将提供一种手段，以比较全球气候变化记录，了解其主要驱动因素，并阐明南极冰盖在一个主要的，从上新世到更新世的全球气候变化。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响审查标准。

The potential for future sea level rise from melting and collapse of Antarctic ice sheets and glaciers is concerning. We can improve our understanding of how water is exchanged between Antarctic ice sheets and the ocean by studying how ice sheets behaved in past climates, especially conditions that were similar to or warmer than those at present. For this project, the research team will document Antarctica’s response across an interval when Earth transitioned from the warm Pliocene into the Pleistocene ice ages by combining marine and land evidence for glacier variations from sites near the Antarctic Peninsula, complimented by detailed work on timescales and fossil evidence for environmental change. An important goal is to test whether Antarctica’s glaciers changed at the same time as glaciers in the Northern Hemisphere as Earth's most recent Ice Age intensified, or alternatively responded to regional climate forcing in the Southern Hemisphere. Eleven investigators from seven US institutions, as well as Argentine collaborators, will study new sediment cores from the International Ocean Discovery Program, as well as legacy cores from that program and on-land outcrops on James Ross Island. The group embraces a vertically integrated research program that allows high school, undergraduate, graduate, post-docs and faculty to work together on the same projects. This structure leverages the benefits of near-peer mentoring and the development of a robust collaborative research network while allowing all participants to take ownership of different parts of the project. All members of the team are firmly committed to attracting researchers from under-represented groups and will do this through existing channels as well as via co-creating programming that centers the perspectives of diverse students in conversations about sea-level rise and climate change.The proposed research seeks to understand phasing between Northern and Southern Hemisphere glacier and climate changes, as a means to understand drivers and teleconnections. The dynamics of past Antarctic glaciation can be studied using the unique isotope geochemical and mineralogic fingerprints from glacial sectors tied to a well-constrained time model for the stratigraphic successions. The proposed work would further refine the stratigraphic context through coupled biostratigraphic and magnetostratigraphic work. The magnitude of iceberg calving and paths of icebergs will be revealed using the flux, geochemical and mineralogic signatures, and 40Ar/39Ar and U-Pb geochronology of ice-rafted detritus. These provenance tracers will establish which sectors of Antarctica’s ice sheets are more vulnerable to collapse, and the timing and pacing of these events will be revealed by their stratigraphic context. Additionally, the team will work with Argentine collaborators to connect the marine and terrestrial records by studying glacier records intercalated with volcanic flows on James Ross Island. These new constraints will be integrated with a state of the art ice-sheet model to link changes in ice dynamics with their underlying causes. Together, these tight stratigraphic constraints, geochemical signatures, and ice-sheet model simulations will provide a means to compare to the global records of climate change, understand their primary drivers, and elucidate the role of the Antarctic ice sheet in a major, global climatic shift from the Pliocene into the Pleistocene.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.