硼同位素在矿床学中的应用研究

硼在自然界有两种稳定同位素11B和10B,常采用δ(11B)/10-3来表示不同地质体的同位素组成。由于硼同位素在不同地质体中的分馏作用大,在较大温度范围内岩浆-热液流体中的高活动性和化学性质稳定等方面的优势,使硼同位素在地球科学研究中的作用越来越广泛。控制硼同位素分馏的主要因素是硼源。一般情况下,非海相的硼酸盐矿物和与之相关的电气石的δ(11B)值为负值,而在某些盐湖卤水和与海相环境有关的硼酸盐矿物的δ(11B)值则为正值。目前,硼同位素示踪主要应用于块状硫化物矿床、与花岗岩有关的热液矿床以及盐湖矿床的研究。随着硼同位素分馏机制及其在不同环境地质样品中分布特征的深入研究,硼同位素在解决矿床的成矿物质来源、矿床成因和成矿作用等方面将发挥更大的作用。

STUDY ON BORON ISOTOPE AND APPLICATION TO STUDY ON MINERAL DEPOSIT

In nature, boron has two stable isotopes (~(10)B and ~(11)B), usually δ~(11)B/10~(-3) values as the isotopic composition of geological bodys. As severe large fractionation between the two isotopes of ~(10)B and ~(11)B in nature, high mobility of boron during both magmatic and fluid-related processes within a large temperature range takes place and lacks complexity associated with oxidation/reduction reactions, boron isotope has been developed in recent years as a powerful geochemical tool. The main factor of controlling boron isotope fractionation is the source of boron. Commonly, δ~(11)B of the non-marine borate minerals and tourmaline is of negative value and δ~(11)B of some salt lake and the marine minerals is positive. Because of the notable characteristics, there are great progresses in application to study on ore deposits, especially in the massive sulfide deposits ,in the granite-ralated hydrothermal deposts and in salt lake deposits.Geochemistry of boron isotope has been applied widely. There are great success to solve the material source of mineralization, genesis of minenal depositsand so on.