摘要
运用地球化学的方法,通过研究沉积岩或沉积物中各常量、微量元素及各种同位素特征,来示踪古沉积环境,以了解当时的沉积特征。通过Sr/Ba法、硼元素法、碳氧同位素法等地球化学指标判定海相沉积还是陆相沉积及了解古盐度信息;不同气候条件下特定元素(如P、Sr等)含量及元素比值(如Sr/Cu、Mg/Ca)可指示特定的古气候条件;沉积水体的氧化还原状态可通过氧化还原敏感元素(如Mo、U、V、Ni、Ce、Eu等)的分析得到较好的恢复;古水深以及海平面的相对变化则利用了元素迁移能力的差异,通过查明不同深度带沉积的元素组合(Fe族、Mn族)、比值(Sr/Ba、Sr/Ca)及同位素(87Sr/86Sr比值)的不同加以判定。沉积环境的地球化学特征同样可以用来判定沉积物源、物源岩性和构造背景及热水沉积。
With the use of geochemical methods,by studying the characteristics of major and trace elements and element isotopic characteristics,the ancient sedimentary environments can be rebuilt,so as to define their sedimentary facies.Marine facies or continental facies and their paleosalinities can be determined and detected in terms of Sr/Ba ratios,borium contents-O isotopes and so on;the contents of specific elements（such as P,Sr） and element ratios（such as Sr/Cu,Mg/Ca） under particular climate conditions are the indicators of that climate;redox sensitive elements（such as Mo,U,V,Ni,Ce and Eu） are the best recorders of redox conditions;because of differences in element migration ability,the determination of water depths and the fluctuations of sea level can be made from element associations（such as Fe group,Mn group）,element ratios（such as Sr/Ba,Sr/Ca） and isotopes（87Sr/86Sr）.Thus,we can also identify their provenances,source rocks＇ lithologies and tectonic settings,as well as hydrothermal deposition or not.
出处
《地球与环境》
CAS
CSCD
北大核心
2011年第3期405-414,共10页
Earth and Environment
基金
国家重点基础研究发展计划项目(2007CB411408)
矿床地球化学国家重点实验室专项经费KCZX2010资助
关键词
沉积古环境
地球化学
元素
示踪
sedimentary paleoenvironment
geochemistry
element
indicator
