浅析马达加斯加铬铁矿主要地质特征

Brief Analysis of Main Geological Characteristics of Chromite in Madagascar

马达加斯加属于非洲克拉通组成部分,以寒武纪构造—岩浆—变质杂岩为主,地层主要由太古界和晚元古界岩石组成,并在泛非洲构造运动期间受到改造,广泛发育有片麻岩绿岩体。该区经历了多期韧性剪切带变形,伴随有花岗岩—闪长岩、基性—超基性岩侵入,这也是铬、金、镍、铂族元素矿产的主要产出母岩。马达加斯加主要铬矿产地位于马达加斯加2号绿岩带-Andriamena绿岩带,铬铁矿为超基性流体岩浆经结晶分异作用堆积形成的阿尔卑斯型豆荚状铬矿床,铬矿体为豆荚状、脉状、似层状和透镜状,铬铁矿大小与超基性岩的规模正相关。

Madagascar,belonging to the African craton part,mainly consists of the Cambrian tectonic magmatic metamorphic rocks,the strata are mainly composed of Archean and late Proterozoic rocks. They were reformed during the Pan African tectonic movement,and gneiss green bodies were widely developed. It has undergone a multistage ductile shear zone,accompanied by intrusions of granite diorite and basic ultrabasic rocks,which are also the main output parent rocks of the chromium,gold,nickel and platinum group minerals. The main ore origin of Malaysia is located at No. 2 Madagascar greenstone belt-Andriamena greenstone belt. Chromite is an Alps shaped chromic deposit formed by the accumulation of ultrabasic magma through crystallization differentiation. The chromic orebodies are usually in shape of pod,vein,stratoid and lenticular and the size of chromite is positively related to the scale of ultrabasic rocks.