矿物稳定同位素地球化学研究

GEOCHEMICAL STUDIES OF STABLE ISOTOPES IN MINERALS

通过测定矿物中元素H ,C ,O和S的同位素比值 ,认识矿物体系中的同位素效应 ,不仅能够确定矿物之间和矿物与流体之间的同位素平衡关系 ,而且能够了解影响矿物平衡和动力学同位素性质的因素。文中评述了稳定同位素分馏系数校准的理论计算、实验测定和经验估计方法 ,讨论温度、压力、化学成分和晶体结构等对矿物同位素性质的影响。由于同位素效应取决于矿物的物理和化学性质 ,因此应用稳定同位素来作为示踪剂不仅能够追索各种矿物学反应的路径 ,而且能够提供证据来阐明矿物晶体结构的某些细节。

The isotope compositions of hydrogen,carbon,oxygen and sulfur in minerals have been successfully applied to recognize isotopic effects in mineralogical systems.The results not only indicate equilibrium relationship between minerals and between mineral and fluid,but also provide insight into the factors affecting the properties of thermodynamics and kinetics of isotopic exchange between them.This paper reviews the methodology of calibrating stable isotope fractionation factors by means of theoretical calculations,experimental determinations and empirical estimates,and discusses the influences of temperature,pressure,chemical composition,crystal structure and salt concentration in solution on isotopic fractionation.Because the isotopic effects depend on the physical and chemical proporties of minerals,stable isotope analysis can be applied to trace the reaction paths of mineralogical reactions and provide evidence for elucidating details of crystal structure.