Collaborative Research: EAGER--Evaluating Fluid Inclusion Geochemistry of U-Th Dated Speleothems as a Tool for Resolving Paleoclimate Controversies in the American Southwest

合作研究：EAGER——评估 U-Th 定年洞穴的流体包裹体地球化学，作为解决美国西南部古气候争议的工具

• 批准号: 1420079
• 负责人: Isabel Montañez
• 金额: $ 11.42万
• 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: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1420079&HistoricalAwards=false
• 关键词: Collaborative; Research; EAGER; Evaluating; Fluid

Global hydrologic reorganization throughout the Northern Hemisphere occurred synchronously with repeated large, sub-millennial-scale climate changes in the northern North Atlantic region during the last deglaciation. However, how this reorganization affected the continental hydroclimate in the drought-prone American Southwest remains poorly resolved. Continental-based paleoclimate reconstructions for this region are contradictory in large part due to two sources of discrepancy: (1) uncertainty in age constraints, and (2) fundamental ambiguity in speleothem-based proxy records.This project-- a collaborative effort between scientists from the University of California at Davis and Harvard University-- seeks to resolve the apparent contradictions in the inferred glacial-interglacial climate reconstructions for the American Southwest using cave deposits from the Sierra Nevada in California. The researchers will employ novel techniques to generate both a robust chronologic framework (using U-Th dating via laser ablation MC-ICPMS) and a record of precipitation (using temperature-dependent noble gas concentrations in fluid inclusions as a temperature proxy independent of other climate processes and stable isotopic composition of inclusion fluids as a more direct proxy of precipitation composition and source region) over the past ~20,000 years at the study site. Successful proof-of-concept of these innovative approaches would open the door for applications to a wide variety of questions in paleoclimate.The outcomes of this work should lead to better understanding of how climate change impacts the hydroclimate of the American Southwest, an area that is vulnerable to water resource limitation. Additional broader impacts include development of a new facility for routine high-precision U-series dating (of which there are only a handful in the US), development of the noble gas proxy in carbonates, and training of graduate students at two institutions.

全球水文重组整个北半球是同步发生的，在上次退化期间，北大西洋北部北部地区的重复大型，千禧一代的气候变化发生。但是，这种重组如何影响易于干旱的美国西南部的大陆氢化气候的解决方案仍然很差。该地区对该地区的基于大陆的古气候重建在很大程度上是矛盾的，这是由于两种差异的来源：（1）年龄限制的不确定性，以及（2）基于斯佩雷索姆的代理记录的基本歧义，这是该项目 - 这项项目 - 这项项目 - 在加利福尼亚大学的戴维斯和哈佛大学科学家之间的协作努力，以解决戴维斯和哈佛大学之间的努力。美国西南部使用来自加利福尼亚山脉的洞穴矿床的气候重建。研究人员将采用新技术来生成稳健的年代学框架（使用激光消融MC-ICPMS的u-th日期）和降水记录（使用温度依赖性的贵气体浓度在温度定位中使用温度依赖性的质量浓度，作为一种与其他气候过程相关的降压量，而稳定的同位素构成，则是持续量的稳定量，这是一个更高的同位素组成部分。研究地点。这些创新方法的成功概念概念将为对古气候中的各种问题的应用打开大门。这项工作的结果应更好地理解气候变化如何影响美国西南部的氢化物，这是一个容易受水资源限制的领域。其他更广泛的影响包括开发一个新的设施，用于常规的高精度U系列约会（美国只有少数），碳酸盐质量代理的发展以及两个机构的研究生培训。