环境同位素记录中共生碳酸盐氧同位素分馏差值的影响  

Effect of Oxygen Stable-Isotope Fractionation between Co-existing Carbonates on Environmental Isotopic Record

作　　者：曾承[1] 余俊清[1] 

机构地区：[1]中国科学院青海盐湖研究所西安二部,陕西西安710043

出　　处：《盐湖研究》2004年第2期14-18,共5页Journal of Salt Lake Research

基　　金：中科院青海盐湖所创新领域前沿项目(CX200302);国家自然科学基金面上项目(49971074);中科院资环创新重大项目(KZCX1-Y-05)

摘　　要：湖泊化学沉积碳酸盐δ18O是研究区域气候演变的重要环境指标之一。青海湖等闭流湖泊的研究结果证实,在对δ18O环境记录进行共生碳酸盐氧同位素分馏效应校正时,应依据具体情况,采用0-1‰的分馏差值。由高温实验结果推断出的常温分馏差值(4‰-7‰)不能被应用到自然条件下湖泊共生碳酸盐氧同位素分馏效应的校正。δ^(18)O of lacustrine inorganic carbonates is one of the important environmental proxies for the study of regional climatic evolution.Results from Lake Qinghai and other closed-basin lakes indicate that isotope fractionation between co-existing carbonates formed naturally in lake environments is minimum.The fractionation differences of 4‰～7‰ in δ^(18)O　between dolomite and calcite,obtained based on elevated-temperature experiments and extrapolations to temperatures at 20℃～25℃,are not applicable to the carbonates formed in natural environments.The fractionation differences of 0～1‰ are recommended for calibrating a possible disparity between co-existing carbonates in lacustrine isotopic records.

关 键 词：共生碳酸盐 氧同位素分馏 沉积学 环境同位素 

分 类 号：P597[天文地球—地球化学] P512.2[天文地球—地质学]