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

该项目旨在重建和调查南非最后一次冰川-间冰期转变(约90,000-60,000年前)期间气候变化的驱动因素。具体地说，该项目将使用南非南海岸洞穴记录中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，以解决以下问题：1)最后一次冰期-间冰期转换时全球边界条件的变化如何影响南非南海岸的水气候？2)在降雨形成和降雨季节性期间，水气候的变化与大气环流和天气条件的变化有何关系？3)这些高分辨率替代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，该项目将确定洞穴中与年轻的托巴喷发有关的硫磺峰，以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异性的理解，并为植物多样性的演变和现代人类行为提供背景。该项目产生的古气候替代记录将为建立一个模型提供信息，该模型将重建人们在该地区遇到的资源景观，从而使人们对狩猎-采集适应其环境的重要理解有所了解。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，本科生的培训，对博士后研究人员和早期职业科学家的支持。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.