新疆哈密东盐池附近变质基底特征及控矿探讨

Metamorphic basement in East Yanchi of Hami,Xinjiang with discussion on the ore controlling

新疆哈密东盐池附近变质基底属于塔里木板块北缘北山古生代裂谷带西段一部分,而板块北缘的北山地区古生代进入了陆块裂解、陆内裂谷发展演化时期。笔者对东盐池附近的变质岩进行了研究,将该区域变质作用分为区域变质、动力变质及接触变质等3个类型;将区内变质相分为低角闪岩相、高绿片岩相、低绿片岩相及葡萄石—绿纤石相等4个变质相带相系。研究了地质事件与变质变形的演化趋势,即变质作用从区域中高温变质、区域低温动力变质到区域埋深变质,变质作用的温度和压力随时代更新逐次降低。探讨了变质作用与矿产的关系,即变质作用控制变质矿产的分布。各种变质作用所形成的热液与其他热液一起促使成矿物质的活化迁移至有利部位成矿,形成了黑色岩系中的磷矿、石墨矿和钒矿等。

The metamorphic basement located in East Yanchi of Hami,Xinjiang belonged to western Beishan Palaeozoic rift belt of Tarim plate＇s northern margin,which was in development period of land block cracking and intracontinental rifting during the Paleozoic.Based on systematic study of metamorphic rocks and metamorphism in East Yanchi,the authors divided the metamorphism into regional metamorphism,dynamic metamorphism and contact metamorphism,and divided the metamorphic facies into low amphibolite facies,high greenschist facies,low greenschist facies and prehnite-pumpellyite facies.The metamorphism order,along the age being younger,is from mediu-high temperature in regional to low temperature dynamic metamorphism,then to deep buried metapmorphism,and p-T successive dropped.The authors also discussed on the connection between metamorphism and mineralization that the metamorphism controlled the distributing of metamorphic minerals.The hydrotherm from metamorphism and others caused the metallogenic materials migrating to favorable positions,which formed graphite,phosphorite and vanadium deposits.