冀东太古代侵入体浅析

Archean intrusions of Jidong

太古代侵入体按其生成环境分为浅成侵入体和深成侵入体,其中,浅成侵入体处于高温低压环境,其特征是它侵入地壳上部冷的地壳中,因此其中的斜长石常具半自形结构和冷凝边,岩石结构常为中细粒结构。太古代深成侵入体处于高温高压的环境,其本身含有大量的挥发组分,并处于封闭的条件下,岩石中的矿物结晶时间较长,所以矿物结构常是粗粒的。表壳岩常为中细粒变晶结构且常保存原岩的变余层理等。混合岩是介于表壳岩与太古代深成侵入体之间的过度岩石类型。太古代侵入体或多或少有一些变质铁矿的包体。

According to their build environment, Archean intrusions divided into shallow intrusive body and plutonic intrusive body, the former in high-temperature low-pressure environment, whose characteristic is that invaded in the cold crust the upper crust, in which plagioclase has semi-shaped structure and condensation side, the rock structure is usually mid-ifne grained structure. Archean plutonic intrusive body in high temperature and high pressure environment, which contain a lot of volatile components, and in closed condition. Mineral crystallzation time is long in rocks, so the mineral structure is often coarse. Supracrustal rocks often in mid-fine crystalloblastic texture and often save the original rock palimpsest bedding and so on. Migmatite is trasitional type between Archean supracrustal rocks and plutonic intrusions rocks. Archean intrusive body has more or less some metamorphic iron ore inclusions.