辽宁新甸金矿床成因

元古宇辽河群盖县组是一套黏土、半黏土质陆源碎屑沉积夹中-酸性火山岩或火山碎屑岩沉积建造，在地质历史发展过程中发生了变形变质作用，导致岩石中的硅质成分分异而形成硅化石英脉，同时，岩石中的成矿物质也发生了初步的迁移和富集.燕山期的花岗岩浆活动交代重熔了变质岩系，变质岩系中大量的成矿物质被活化、迁移至岩浆期后热液中，在成矿热液演化为偏酸性-还原性条件下，金等成矿元素发生了沉淀作用.稳定同位素、稀土元素特征表明金矿床的成矿物质来源于盖县组变质岩系，成矿热液为岩浆期后热液.伴随岩浆活动产生的一系列剪切构造既为成矿热液运移提供了通道，也为矿质沉淀提供了有利空间.新甸金矿床属于岩浆期后热液型矿床.

THE GENESIS OF THE XINDIAN GOLD DEPOSIT IN LIAONING PROVINCE

The Gaixian formation of Liaohe group is composed of terrigenous clastic clayey sedimentary rocks interlayered by acid intermediate volcanic rocks and/or volcanic clastic sedimentary rocks.The siliceous veins are formed by metamorphic defferentiation in the long geologic era.In the process,Au and other mineralizing materials in the metamorphic rocks were firstly activated and then migrated and enriched in the siliceous veins.In Yanshanian epoch,the metamorphic rocks were metasomated and resoluted,and formed porphyroid biotite granite.The Au and other mineralizing materials were mostly migrated into post magmatic hydrothermal fluid,and not precipitated until the fluid varied to weak acid and reductive solution.The characteristics of Pb and S isotopes and chondrite normalized REE pattern prove that the mineralizing materials are from Gaixian formation.The composition of inclusions in quartz and H and O isotopes demonstrate that the mineralizing hydrothermal fluid came from mainly the post magmatic hydrothermal solution.The shearing structures formed by magmatic activities are the migratory channels of the hydrothermal solution and space for the forming of veins or ore bodies.Xindian gold deposit is a post magmatic hydrothermal type of gold deposit.