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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

基本信息

批准号：
0823541
负责人：
Warren Sharp
金额：
$ 6.16万
依托单位：
Berkeley Geochronology Center
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 2012-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0823541&HistoricalAwards=false
关键词：
Collaborative Research P2C2 Continental Response

项目摘要

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.

提供资金用于开发精确日期的、基于洞穴的内华达山脉气候变化的高分辨率记录。研究人员正在检验两个假设：(1)塞拉利昂洞穴沉积物与滴水在同位素和地球化学平衡中沉淀，从而记录了区域降水、温度和植被密度的短暂变化；(2)由于气候系统的大规模重组，北美西部中纬度地区极地急流和相关冬季风暴路径的位置变化被记录在塞拉利昂洞穴沉积物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)完成对地表、土壤和洞穴条件的原位测量；2)分析现代滴水和源水以及新近形成的方解石沉淀中的同位素和微量元素含量，以确定滴水和喷发方解石中自然的洞穴内和洞间变异性，并评估洞穴方解石是否存在同位素和微量元素平衡降水；3)对三个洞穴的石笋进行精确的定年(U系列，精度优于2%)。更广泛的影响包括更好地了解冬季风暴路径和北美西部中纬度地区的年平均降水量对北部高纬度条件随大气温度变暖的变化的敏感性。该项目还帮助资助了两名参与研究的研究生。