老挝龙湖矿区ZK309农波组中盐段泥岩层硼的地球化学特征研究

Boron Geochemical Characteristics of Nongbo Group Salt Mudstone Strata in ZK309 Hole,Longhu Diggings, Laos

中文关键词:  老挝龙湖钾盐矿区  硼及硼同位素  混合水  吸附作用

英文关键词::Longhu potash mining area  Boron and boron isotopie  Mixed water  Adsorption封面图片:大柴旦盐湖 大柴旦盐湖位于柴达木盆地北部的次级山间盆地中,其常年卤水湖加上干盐湖的总面积约为235km²,以蕴藏固体硼矿为特色,钾,锂等资源尚待开发。大柴旦盐湖以其独特的地质地貌和水文气候特征为我们提供了研究盐湖硼,锂,钾等矿产资源形成的物质来源,成矿过程,水文条件,矿体分布规律的天然实验室。研究成果将为丰富盐湖硼矿成因理论,助推盐湖成盐演化,成矿规律的研究走向世界前沿做出贡献(图片拍摄于2016年10月31日)。 (中国科学院青海盐湖研究所 余俊清)

中文摘要:

      由于硼(B)在自然界中分布较集中,平均丰度低,而且¹¹B和¹⁰B之间质量差大,分馏效应显著,故元素硼及其同位素组成可以作为指相标志来判定硼来源和沉积环境。龙湖钾盐矿区是呵叻高原钾盐矿在老挝境内最主要的矿区之一,ZK309钻孔在龙湖矿区具有代表性。对该钻孔盐岩上覆碎屑层的硼元素及其同位素的分析,B含量56×10-6～103×10-6(wt.%),平均值为73×10-6；δ¹¹B的范围为+7.44‰到+11.62‰,平均+8.96‰,介于海水的δ¹¹B值(+39.5‰)及陆相地下水的δ¹¹B值(-3±5‰)之间,B的含量指示中盐段岩盐层沉积后期曾明显有水流体的活动,这种水流体表现出偏向于淡水、咸水混合水特征,而B同位素研究说明粘土矿物的吸附作用是δ¹¹B降低的主要因素。

英文摘要:

      :Boron is relatively concentrated distribution in nature,the average B is low,¹¹B and ¹⁰B have different quality.The fractionation effect is significant,so the boron and its isotopes composition may be used to determine the effective boron source indicator and facies marks.ZK309 drilling is the most representative in Longhu mining area, through the borehole rock overlying clast layer of boron and its isotopes analysis,B content(56×10-6～103×10-6,wt.%),the average was 73×10-6,the¹¹B range from +7.44‰ to +11.62‰, obvious different between seawater ¹¹B value (+39.5‰) δ¹¹B and the terrestrial groundwater value between-3±5‰. Through the content of boron analysis, the sedimentary process of salt rock salt has obvious water fluid activity, this water biased in the characteristics of fresh water and salt water, the boron isotopic constitute study adsorption of clay minerals is the main factor that make δ¹¹B reduced.