地幔交代作用

地幔交代作用是地球内部的一种化学变化。从200公里深处由高速喷发带上来的地幔岩块的研究表明,在熔融之前某些含挥发组分的交代矿物已经存在。地幔交代作用的提出,是用以解释硷性岩浆的化学组成和同位素体系变化的原因。硷性岩浆作用广泛的时空分布表明,地幔交代作用是广泛的,并且是长期的一种地质作用。它不仅是引起地幔化学上和氧化还原条件变化的主要因素之一,而且是产生硷性岩浆的理想源区和引起克拉通地区陆壳抬升的动因之一。

MANTLE METASOMATISM

Mantle metasomatism is a process of continuing chemical change with in the earth.Mantle fragments carried up from as deep as 200 km by high-velocity volcanic eruptions show volatile-bearing metasomatic minerals were present in mantle before it underwent melting. The wide spatial and temporal distribution of alkaline magmatism shows that mantle metasomatism is a widespread,long-lived and continuous geological process. It is not only one of the main factors which causes chemical heterogeneity end chtnge of condition of oxidation-reduction in the mantle,but also a factor causes the origination of alkaline magmas regarding both their drivation and emplacement in the crust,and it is by the latter process the uplifting of cratons.