Stable Isotope Geochemistry

稳定同位素地球化学

• 批准号: 0439925
• 负责人: Robert Clayton
• 金额: $ 33.12万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0439925&HistoricalAwards=false
• 关键词: Stable; Isotope; Geochemistry

ClaytonEAR-0439925Non-mass-dependent (NMD) isotope effects in sulfur and oxygen will be used to study two topics in the geochemistry and evolution of Earth's atmosphere. It has been proposed by others that the observed NMD effects in sulfur in Archean rocks are due to ultraviolet photochemistry in the stratosphere before the existence of an effective ozone shield. The underlying photochemistry will be studied in systematic laboratory experiments involving photolysis of sulfur dioxide. Determination of the timing and mechanism for the development of an oxygen-rich atmosphere is an important factor in biological evolution. The second study deals with the modern atmosphere, and consists of a search for NMD signals in tropospheric oxygen-bearing molecules, acquired from stratospheric ozone, and transported across the tropopause. Samples to be analyzed include ice cores from low-latitude, high-altitude glaciers, which may provide a millennial record of atmospheric dynamics. Both of these studies are of practical importance in understanding the chemical workings of our atmosphere. This work will constitute the doctoral theses of two graduate students.

硫和氧的非质量依赖（NMD）同位素效应将用于研究地球化学和地球大气演化中的两个主题。其他人已经提出，观测到的太古宙岩石中硫的NMD效应是由于在有效的臭氧屏蔽存在之前平流层中的紫外线光化学作用。潜在的光化学将在系统的实验室实验中研究，涉及二氧化硫的光解。确定富氧大气形成的时间和机制是生物进化的一个重要因素。第二项研究涉及现代大气，包括在对流层含氧分子中寻找NMD信号，这些分子是从平流层臭氧中获得的，并通过对流层顶运输。待分析的样本包括来自低纬度、高海拔冰川的冰芯，这些冰芯可能提供千年来大气动力学的记录。这两项研究对了解大气的化学作用都具有实际意义。这项工作将构成两名研究生的博士论文。