Collaborative Research: P2C2--South African Hydroclimate Reconstructions Using Speleothem Multiproxy Analyses

该项目旨在重建和研究南非末次冰期-间冰期（~9万-6万年前）气候变率的驱动因素。具体而言，该项目将利用南非南海岸岩洞记录的高分辨率微量元素分析（主要是镁、锶和钡）和氧稳定同位素来解决以下问题：1)末次冰期-间冰期过渡期间全球边界条件的变化如何影响南非南部海岸的水文气候？2)在降雨形成和降雨季节期间，水文气候的变化与大气环流和天气条件的变化有何关系？3)这些高分辨率的代用记录与南半球和北半球千年尺度的气候变化有何关系？此外，该项目将确定与多巴火山喷发有关的洞穴中的硫峰，并将这些记录与来自两个半球的冰芯记录联系起来。潜在的更广泛的影响包括在南非产生一个新的多代理水文气候记录。这一记录将进一步加深对该地区过去气候变化的认识，并为植物多样性和现代人类行为的演变提供背景。该项目产生的古气候代理记录将为模型的发展提供信息，该模型可以重建人们在该地区遇到的资源景观，从而为对狩猎采集者适应环境的关键理解提供信息。其他更广泛的影响包括加强多机构和国际合作，以开发多代理洞穴记录，培训本科生，支持博士后研究员和早期职业科学家。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project aims to reconstruct and investigate drivers of climate variability during the last glacial-interglacial transition in South Africa (~90,000-60,000 years ago). Specifically, this project will use high resolution trace element analyses (mainly magnesium, strontium and barium) and Oxygen stable isotopes from speleothem records located in the South African south coast to address the following questions: 1) How did changes in global boundary conditions at the last glacial-interglacial transition affect hydroclimate on the southern coast of South Africa? 2) How are changes in hydroclimate related to variations of atmospheric circulation and synoptic conditions during rainfall formation and rainfall seasonality? 3) How are these high-resolution proxy records related to millennial scale climate variations in the southern and northern hemisphere? Additionally, this project will identify sulfur peaks in the speleothems that are associated with the younger Toba eruption to link these records to ice core records from both hemispheres. The potential Broader Impacts include generating a new multi-proxy hydroclimate record in South Africa. This record will further the understanding of past climate variability in this region and provide a context for the evolution of plant diversity and modern human behaviors. The paleoclimate proxy records produced by this project will inform the development of a model that reconstructs the resource landscape that people have encountered in this region and thus inform the critical understanding of hunter-gatherer adaptations to their environments. Other Broader Impacts include strengthening multi-institution and international collaborations to develop a multi-proxy speleothem record, the training of undergraduate students, support for a post-doctoral researcher and an early career scientist.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.