Collaborative Research: Quantitative Paleoclimatology of the East African Monsoon

合作研究：东非季风的定量古气候学

• 批准号: 2103009
• 负责人: William Lukens
• 金额: $ 11.93万
• 依托单位: James Madison University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2103009&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantitative; Paleoclimatology; East

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The East African Monsoon (EAM) provides intense, seasonal rains that are critically linked to food security and infrastructure for a large portion of global population. The timing and amount of these rains are projected to change substantially under anthropogenic climate change. Studying past intervals of global warmth can inform the scientific community and general public on the direction and magnitude of change in EAM characteristics as the planet warms and cools. This project aims to leverage a large archive of fossil soil (paleosol) samples collected from the Baringo Basin of Kenya, Africa, to reconstruct aspects of past hydroclimate and temperature during the Pliocene-Pleistocene epochs (~4.1-2.6 million years ago). This work will produce the first quantitative estimates of precipitation and temperature across intervals of warming and cooling, including the last time that atmospheric CO2 reached current levels. The response of vegetation to these climate changes will be also be documented, thereby informing the scientific community on the sensitivity of different plant groups to changes in climate parameters. This work will support a large cohort of undergraduate student researchers and a PhD student, and scientific results will be incorporated into upper level, data-driven geoscience courses.Paleosols were previously described in the field in the vicinity of a coring locality associated with the Hominin Sites and Paleolakes Drilling Project. New analyses will include reconstructing paleoclimate (rainfall, temperature) using robust, multivariate models based on paleosol bulk geochemistry as well as the clumped isotope composition of pedogenic carbonates; vegetation will be reconstructed using stable isotopes from pedogenic carbonates and organic matter. This work will provide the first quantitative paleoclimate estimates from the Baringo Basin, which contains the most continuous Neogene stratigraphic record in equatorial eastern Africa and preserves a rich paleontological and paleoanthropological archive. The results of this work will be placed within an existing, high-resolution geochronologic framework to test hypotheses that relate the effect of CO2 rise to EAM strength, local climate seasonality, and landscape-scale vegetation structure. The project will include outcrop-to-core comparisons to evaluate proxy robustness, thereby strengthening paleoclimate and paleoenvironmental interpretations. The multi-proxy approach will allow for rigorous testing of proxy robustness and repeatability.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.

该奖项的全部或部分资金根据《2021 年美国救援计划法案》（公法 117-2）提供。东非季风 (EAM) 带来强烈的季节性降雨，这与大部分地区的粮食安全和基础设施密切相关全球人口。在人为气候变化的影响下，这些降雨的时间和数量预计将发生重大变化。研究过去全球变暖的时间间隔可以让科学界和公众了解随着地球变暖和变冷，EAM 特征变化的方向和幅度。该项目旨在利用从非洲肯尼亚巴林戈盆地采集的大量化石土壤（古土壤）样本，重建上新世-更新世（约 4.1-260 万年前）过去的水文气候和温度。这项工作将对变暖和变冷期间的降水和温度进行首次定量估计，包括大气二氧化碳达到当前水平的最后一次。植被对这些气候变化的反应也将被记录下来，从而向科学界通报不同植物群对气候参数变化的敏感性。这项工作将为一大批本科生研究人员和一名博士生提供支持，科学成果将被纳入高层、数据驱动的地球科学课程中。 之前在与古人类相关的核心地点附近的领域中描述了古土壤遗址和古湖钻探项目。新的分析将包括使用基于古土壤整体地球化学以及成土碳酸盐的聚集同位素组成的稳健多元模型来重建古气候（降雨量、温度）；将利用成土碳酸盐和有机质的稳定同位素重建植被。这项工作将提供巴林戈盆地的首次定量古气候估计，该盆地包含赤道东非最连续的新近纪地层记录，并保存了丰富的古生物学和古人类学档案。这项工作的结果将置于现有的高分辨率地质年代学框架内，以测试将二氧化碳上升的影响与 EAM 强度、当地气候季节性和景观规模植被结构联系起来的假设。该项目将包括露头与岩心的比较，以评估代理的稳健性，从而加强古气候和古环境的解释。多代理方法将允许对代理稳健性和可重复性进行严格测试。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。