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我国东部地台阶段的地球化学特点是外生地球化学过程占有极重要的地位。外生成矿元素的地球化学富集与地台区构造的关系是:在地台构造发展历史上呈现出垂直分带性;在地台区内部构造位置的空间上,呈现出水平分带性。在内生地球化学作用中,以基性岩浆的元素组合占绝对优势,而且Fe、Ti、V等元素特别集中。按V.M.戈尔德斯密特的元素地球化学分类,地台区以亲石元素(B、C、O、Na、Mg、Al、Si、P、Cl、K、Ca、Mn、Sr、Ba等)的外生地球化学富集作用占优势,此外,还有亲气元素(H等)和亲铁元素(Fe,P为主)的外生地球化学富集。而亲铜元素,除铜有点富集外,其余均分散,而且分配量亦较少。 由地槽区、地台区、地洼区的地球化学特征及其发展和演变过程,可见地球物质的地球化学分异是引起地壳大地构造运动和发展的基本原因之一。
The geochemical characteristics of the platform in the eastern part of our country are that the exogenous geochemical processes play an important role. The relationship between the geochemical enrichment of exogenous ore-forming elements and the tectonic setting of the platform area is as follows: vertical zonation appears in the tectonic development history of the platform; and horizontal zonation appears in the spatial structure of the tectonic site. In the endogenous geochemical processes, the elemental composition of the basic magma occupies an absolutely dominant position, and elements such as Fe, Ti and V are particularly concentrated. According to the element geochemical classification of VM Goldsmidt, the platform area is dominated by lithophile elements (B, C, O, Na, Mg, Al, Si, P, Cl, K, Ca, Mn, Sr, Ba, etc. ) Exogenous geochemical enrichment effect is dominant, in addition, there are progenitor elements (H) and pro-iron elements (Fe, P-based) exogenous geochemical enrichment. The pro-copper, in addition to a little copper enrichment, the rest are dispersed, but also less distribution. Geochemical characteristics of the terrane area, platform area and depression area and their development and evolution shows that the geochemical differentiation of geomaterials is one of the basic reasons for tectonic movement and development of the crustal earth.