Reconstruction of Quaternary Climates Using Stable Isotopic Analyses of Packrat Middens

利用Packrat Middens稳定同位素分析重建第四纪气候

• 批准号: 9631420
• 负责人: Valery Terwilliger
• 金额: --
• 依托单位: University of Kansas Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-15 至 2000-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9631420&HistoricalAwards=false
• 关键词: Reconstruction; Quaternary; Climates; Using; Stable

SBR-9631420 Valery J. Terwilliger U. Kansas This award funds a project to study the climate variations at a regional scale by measuring the stable oxygen, hydrogen and carbon isotopic ratios of plant remains in packrat middens found in two mountain ranges in the western U.S. To constrain the variables that affect the isotopic compositions in plant materials, the PI also propose to grow plants in a greenhouse under controlled conditions. From a climatic study point of view, the 40,000 year-old long plant remains in packrat middens are very valuable samples for stable isotope work. The possibility of comparing leaves and stems provides further advantage to examine the isotopic variations due to a change in source water versus a change in the atmospheric conditions (e.g. humidity). Such isotopic analyses of plant remains are widely used to interpret climate. This project pushes interpretations to address more directed questions about climate at a finer scale than has previously been attempted. To interpret the isotopic records, it is important that the contemporary leaves and stems be studied and compared between the two species and two locations. The controlled experiments proposed are useful for understanding the physiological pathways of oxygen, hydrogen and carbon isotopes. Climatic processes that operate within regional scales are poorly understood. This limited knowledge is the primary reason that predictive models of climatically induced environmental change are least rigorous for small areas. Reconstruction of environmental developments in the climatically changeable Quaternary period is considered to be the most promising source of information for improving the sophistication of these models. This requires not only efforts to answer more directed questions about past environments but also efforts to improve the resolution of climatic inferences that can be made from proxies. This project should contribute to these wider needs for knowledge about environmental development s within small areas.

Valery J. Terwilliger U.堪萨斯该奖项资助了一个项目，通过测量在美国西部两个山脉中发现的食鼠冢中植物遗骸的稳定氧，氢和碳同位素比率来研究区域范围内的气候变化。为了限制影响植物材料中同位素组成的变量，PI还建议在受控条件下在温室中种植植物。从气候研究的角度来看，这具4万年前的长植物遗骸是非常有价值的稳定同位素工作样本。比较叶和茎的可能性提供了进一步的优势，以检查由于源水的变化与大气条件（例如湿度）的变化而引起的同位素变化。这种对植物遗骸的同位素分析被广泛用于解释气候。这个项目推动解释，以解决更直接的问题，在一个更精细的规模比以前的尝试气候。为了解释同位素记录，重要的是研究和比较两个物种和两个地点之间的当代叶和茎。所提出的控制实验对于理解氧、氢和碳同位素的生理途径是有用的。人们对区域尺度内的气候过程知之甚少。这种有限的知识是气候引起的环境变化的预测模型对小地区最不严格的主要原因。在气候多变的第四纪环境发展的重建被认为是最有前途的信息来源，以提高这些模型的复杂性。这不仅需要努力回答关于过去环境的更直接的问题，而且还需要努力提高可以从代理中做出的气候推断的分辨率。这个项目应该有助于这些更广泛的需求，了解小地区内的环境发展。