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: 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

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.

提供了资金来发展内华达山脉气候变化的精确，高分辨率的基于Speleothem的记录。研究人员正在检验两个假设：（1）在同位素和地球化学平衡中与滴水水中沉淀塞拉speleothems，从而在区域降水，温度和植被密度的档案短暂变化中变化； （2）在北部北部纬度北美地区的极地喷气流和相关的冬季风暴轨道的位置，由于气候系统的大规模重组，在塞拉斯皮雷特姆同位素和地球化学组成中被存档。为了检验这些假设，研究人员将：1）完成表面，土壤和洞穴条件的原位测量； 2）分析现代滴水和源水中的同位素和微量元素含量以及最近的方解石沉淀，以定义滴水器和棘齿刻度的天然内和锯齿中的变异性，并评估同位素和痕量元件平衡的存在Speleothem方解石； 3）从三个洞穴的石塔米氏菌（Stalagmites）进行地球化学和同位素时间序列（极度多核分辨率）的精确日期（具有优于2％精度的U系列）。更广泛的影响涉及对冬季风暴轨迹的敏感性和平均年降水量的了解，在北美西部纬度中的年平均降水量对北部高纬度条件的变化随变暖的大气温度变化。该项目还有助于支持参与研究的两名研究生。