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碱性交代岩系指各种基体在一定的地质环境下经受碱交代作用的产物。一般与侵入杂岩没有明显的成因联系(少数与碱性侵入杂岩有关),具有独特的岩石学和矿物-地球化学特征。形成交代岩的基体可以是酸性或碱性侵入岩,也有喷出岩,但主要是沉积-变质岩。 近十多年来,在苏联各地区以及非洲等地陆续发现各种类型的碱性交代岩体。研究表明,碱性交代岩中蕴藏着丰富的稀有金属和非金属矿产资源。已查明有Be、Nb、Ta、zr、TR以及冰晶石、萤石、霞石、蛭石等矿种。因此,碱性交代岩已成为稀有元素矿床的一个重要类型而受到人们的重视。根据有关资料,本文将其主要地质地球化学特征作一综合介绍。
Alkaline metasomatism refers to a variety of substrates in a certain geological environment to withstand the role of alkali products. Generally, there is no obvious genetic relationship with intrusive complexes (a few are related to alkaline intrusive complexes) with unique petrology and mineralogical-geochemical characteristics. The matrix that forms metasomatism can be acidic or alkaline intrusive rocks, but also extrusive rocks, but mainly sedimentary-metamorphic rocks. In the past decade or so, various types of alkaline metamorphic rocks have been successively discovered in various regions of the Soviet Union and in Africa. The research shows that alkaline metamorphic rocks are rich in rare and non-metallic mineral resources. Has identified Be, Nb, Ta, zr, TR and cryolite, fluorite, nepheline, vermiculite and other minerals. Therefore, alkaline metamorphic rocks have become an important type of rare element deposits and received great attention. According to the relevant data, this article will make a comprehensive introduction of its main geological geochemical characteristics.