投稿时间：2015-01-06
修订日期：2015-12-25
网络发布日期：2016-02-24
中文摘要:硼在自然界中分布较集中,平均丰度低,而且11B和10 B之间质量差大,分馏效应显著,故B同位素的组成可以作为判定硼来源及沉积环境的有效 指示剂和指相标志。文章对老挝龙湖钾盐矿区ZK309钻孔盐岩上覆泥岩层的B同位素地球化学 及矿物学进行分析总结得出,其δ11B范围为744‰～1162‰,均值896‰,明 显介于海水的δ11B值(395‰)与陆相地下水的δ11B值(-3‰±5‰)之间 ；钻孔的矿物组成保存了一定的母岩特性,石英明显来自于陆源输入物；而石盐、硬石膏、 石膏与残余卤水有关,推测在下盐段后期出现陆源淡水输入事件,使得后期盐岩层被淋滤, 而泥岩层的δ11B值就是受淋滤后的残余卤水影响的结果,这也解释了蒸发岩沉积层 序异常(钾石盐覆盖于光卤石之上)的沉积特征。
Abstract:Because boron exhibits relatively concentrated distribution in nature, has low a verage abundance, and the quality is different between 11B and 10 B, the fractionation effect is significant. Therefore, the boron isotopic comp osition may be used to determine the effective boron source indicator and facies. The Longhu po tash mining area is one of the main potash mines in Khorat plateau of Laos, and drill hole ZK309 is the representative in the Longhu mining area. The boron isot ope geochemical and mineralogical analyses of the salt rock overlying mudstone l ayers in this drill hole indicate that the δ11B values range from 744‰ to 1162‰, 896‰ on average,obviously between δ11B value of seawate r (395‰) and the terrestrial groundwater value (-3‰±5‰), mineral compo siti on in the drill hole preserved some characteristics of parent rocks, and quartz is sourced obviously from terrigenous materials. In addition, halite,anhydrite and gypsum are related to residual brine. It is inferred that the rock salt depo sition was impacted by terrigenous water at the late stage,and the mudstones we re reformed by brine after deposition. The brine might have been generated from dissolution of the underlying salt rocks by meteoric water. This could ex plain the abnormal sequence of salt rock deposition (sylvite overlies carnallite ).
文章编号：
中图分类号：P619.211
文献标志码：
基金项目:本文得到国家自然科学基金项目(编号:40903014)和中国科学院青海盐湖研究所青年引导基金联合资助
引用文本：
唐启亮,张西营,李雯霞,韩元红.2016.老挝龙湖矿区泥岩层B同位素地球化学初步研究——以ZK309为例[J].矿床地质,35(1):196~202TANG QiLiang,ZHANG XiYing,LI WenXia,HAN YuanHong.2016.Boron isotope geochemical study of mudstone in Longhu mining area of Laos: A c ase study of ZK309[J].Mineral Deposits35(1):196~202
图/表
