淮南潘二矿太原组灰岩稀土元素特征及沉积环境的分析  

Geochemical characteristics of REE in limestone of the Taiyuan Formation,Paner coalmine and their constraint on depositional environment

作　　者：吴斌[1] 吴盾[1] 万宗启[1] 刘桂建[1] 孙若愚[1] 

机构地区：[1]中国科学院壳幔物质与环境重点实验室,中国科学技术大学地球与空间科学学院,安徽合肥230026

出　　处：《中国科学技术大学学报》2013年第5期355-362,共8页JUSTC

基　　金：国家自然科学基金(40873070);安徽省科技攻关项目(11010401015);淮南矿业集团科技项目资助

摘　　要：选择淮南潘二煤矿石炭系太原组13层灰岩作为研究对象,在岩石学基础上对其稀土元素地球化学特征进行了分析,并探讨了灰岩中稀土元素的来源,进而对其沉积环境进行解释.结果表明:各层灰岩中Zr,Th,Sc含量较低且Y/Ho比值较高,表明各层灰岩均未受到陆源碎屑物的混染;其中轻稀土(LREE)弱亏损、La正异常、Y正异常、高Y/Ho值呈现出与正常海相碳酸盐岩相似的稀土元素特征,这反映了灰岩沉积环境具有典型海相沉积的特征;δCe反映出各层灰岩沉积时氧化还原条件不同;δEu正异常反映了整个灰岩段沉积时处于近海岸环境,并伴随有陆相有机物质分解风化,进而进入灰岩沉积水体中,从而使Eu呈现显著的正异常.Based on a detailed petrologic study, the characteristics of REEs in limestone samples from the Late Carboniferous Epoch Taiyuan Formation in the Huainan Paner coalmine were analyzed. The origin of REEs and the depositional environment of limestone were investigated. Lower concentrations of Zr, Th, Sc, and relatively higher ratios of Y/Ho show that the limestone sediments deposited in a marine environment, with no impact on terrigenous detrital. The characteristics of LREE-depletion, slightly positive La anomaly, positive Y anomaly and hih ratio of Y/Ho show that the the marine carbonate, which indicates that the limestone deposited in a marine environment. However, the Ceanomaly in the limestone samples reflects a transition process of a reducing-oxidizing environment during the deposition. The positive Eu anomaly reflects that the limestone from Taiyuan Formation was formed in a near coastal environment with the input of weathered terrestrial organic matter.

关 键 词：太原组 稀土元素特征 沉积环境 潘二煤矿 

分 类 号：P594[天文地球—地球化学]