Collaborative Research: P2C2--Continental Response to Abrupt Climate Change Post 70 ka: An Integrated Isotopic and Trace Element Study of Sierra Nevada Speleothems

合作研究：P2C2——70 ka后大陆对突然气候变化的响应：内华达山脉洞穴的同位素和微量元素综合研究

• 批准号: 0823656
• 负责人: Isabel Montañez
• 金额: $ 29.16万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0823656&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Continental; Response

Funding is provided to develop precisely dated, high-resolution speleothem-based records of climate change in the Sierra Nevada. The researchers are testing two hypotheses: (1) Sierra speleothems were precipitated in isotopic and geochemical equilibrium with drip waters, and thus archive short-lived changes in regional precipitation, temperature, and vegetation density; and (2) shifts in the position of the polar jet stream and associated winter storm tracks over mid-latitude western North America, forced by large-scale reorganization of the climate system, are archived in Sierra speleothem isotopic and geochemical compositions. To test these hypotheses, the researchers will: 1) complete in situ measurements of surface, soil and cave conditions; 2) analyze the isotopic and trace element contents in modern drip and source waters and recent calcite precipitates to define the natural intra- and inter-cave variability in drip-waters and speleothem calcites and to evaluate the presence of isotopic and trace element equilibrium precipitation of speleothem calcite; and 3) develop precisely dated (U-series with better than 2% precision) geochemical and isotopic time series (minimally multi-decadal-resolution) for stalagmites from three caves. The broader impacts involve improved understanding of the sensitivity of winter storm tracks and mean annual precipitation levels in the mid-latitudes of western North America to changes in northern high-latitude conditions with warming atmospheric temperatures. The project also helps support two graduate students involved with the research.

提供资金，以制定精确的日期，高分辨率的洞穴化石记录的气候变化在内华达州。研究人员正在验证两个假设：（1）塞拉洞穴沉积物是在同位素和地球化学平衡下与滴水沃茨沉淀而成的，因此记录了区域降水、温度和植被密度的短暂变化;和（2）由于气候系统的大规模重组，极地急流和与之相关的北美西部中纬度冬季风暴路径的位置发生了变化，都保存在塞拉利昂洞穴堆积层的同位素和地球化学成分中。为了验证这些假设，研究人员将：1）完成地表、土壤和洞穴条件的原位测量; 2）分析现代滴水和源沃茨以及近期方解石沉淀物中的同位素和微量元素含量，以确定滴水沃茨和洞穴方解石中的自然洞穴内和洞穴间变化，并评估洞穴方解石的同位素和微量元素平衡沉淀的存在;（3）建立三个洞穴石笋的精确定年（精度优于2%的U系列）地球化学和同位素时间序列（最低几十年分辨率）。更广泛的影响包括更好地了解北美西部中纬度地区冬季风暴路径和年平均降水量对北方高纬度地区气温变暖的敏感性。该项目还帮助支持参与研究的两名研究生。