太古宙花岗岩中的暗色包体

在华北陆台北缘太古宙花岗质岩石的成因研究中,对其中的暗色包体进行了较详细的矿物学和岩相学研究,从中获得了许多反映花岗质岩浆来源及其成岩演化过程的信息,从而为花岗岩的岩浆起源提供了证据。这些暗色岩包体按成因及来源可分为:深源火成岩包体,围岩包体及深熔同生包体。研究表明,深源火成岩包体是花岗岩的母岩浆(基性岩浆)的早期结晶分离相,有些包体可能代表岩浆源区—上地幔岩的岩块。而深熔同生包体和围岩包体则是在深熔岩浆的形成过程中母岩中难熔组分的聚集物和岩浆上侵过程中捕获围岩的产物。

DARKCOLOR ENCLAVES IN ARCHEAN GRANITES

Different types of darkcolor enclaves have been distinguished in the north margin of North China Plantform. They are distributed in different types of granites of Archean. These darkcolor enclaves can be divided into three types; deep-seated source igneous enclaves) country rock enclaves and anatexis coproduced eclaves. The study of petrography and mineralogy show the deep-seated source: gneous enclaves have much kinds of igneous structure of basic and ultrabasic rocks and rich in A12O3. HgO. Na2O in mineral composition than that of host rock. These indicate the enclaves may be the early crystallized and segregated pases of the parent magma (may be basic) of granites, some of them may be rock block coming from the source 8 rocks-mantle rocks.The anatexis coproduced enclaves were formed by accumulation of material diffiult to melt of mother rocks or by reproduced of country rock enclave duringanatexism. All of these are evidences for the original study of the Archean granites.