Stable Isotope Geochemistry

轻元素氧、碳和氮同位素丰度的自然变化将被用来研究各种地球化学和宇宙化学问题。通过额外的实验室实验和理论计算，将扩展同位素分馏的基本热力学基础。这些结果将用于确定火成岩和变质岩的热历史。将特别重视来自地幔的岩石，以评估地壳岩石向内陆再循环的程度。将通过陨石中的氧同位素丰度来研究地球的起源及其原材料的性质。三同位素方法是建立早期太阳系不同组成部分之间遗传关系的一个非常强大的工具。陨石研究将侧重于原始碳质球粒陨石，特别是小行星体内的水化和脱水过程。一些碳质球粒陨石含有丰富的有机化合物，包括氨基酸和羧酸，它们可能是在星云中或在小行星母体中形成的。这些化合物的形成地点将通过测量它们的氧同位素组成来确定。

9815338ClaytonNatural variations in the abundances of isotopes of the light elements oxygen, carbon and nitrogen will be used to study a variety of geochemical and cosmochemical problems. The fundamental thermodynamic basis of isotopic fractionation will be expanded by additional laboratory experiments and theoretical calculations. These results will be applied to the determination of thermal histories of igneous and metamorphic rocks. Particular emphasis will be given to rocks from the Earth's mantle in order to assess the degree of recycling of crustal rocks into the interior. The origin of the Earth and the nature of its raw materials will be studied through oxygen isotope abundances in meteorites. The three-isotope method is a very powerful tool for establishing genetic relationships among the various constituents of the early Solar System. Meteorite studies will focus on the primitive carbonaceous chondrites, in particular, on the processes of hydration and dehydration in asteroidal bodies. Some carbonaceous chondrites contain abundant organic compounds, including amino acids and carboxylic acids, which may have been formed either in the nebula or within asteroidal parent bodies. The site of formation of these compounds will be determined by measurements of their oxygen isotopic compositions.