李坝微细粒浸染型金矿矿床成因探讨

A DISCUSSION ON THE GENESIS OF LIBA MICRO-FINE GRANULAR DESSEMINATED GOLD ORE DEPOSIT

李坝微细粒浸染型金矿是一个比较典型的三源成矿热液型矿床,即矿质(矿源)水源、热源有机结合的产物,其成矿物质来源主要来自矿区泥盆系中统舒家坝组(李坝群)地层。水源主要来自大气降水、地层水。热源主要来自中川岩体。在地层水充足和含易活化成矿金属含量较高的岩层共存区,当构造运动、岩浆活动,在热作用下,使地层水受热、溶解活化成矿金属物质,不断渗透运移,渗透运移到一定的有利空间富集成矿。其成矿热液的形成经历了雨水—常温地层水—高温热水—高温含矿热卤水等阶段。即热液是富含矿质的高温水溶液,是由矿质、水和热三要素构成。

Liba micro-fine granular disseminated gold ore deposit is a typical hydrothermal ore deposit with the frormation of three sources. It is a product of organic integration of ore constituents (ore source),water source,and heat source. Its materials of lre's formation are mainly derived from the strata themselves of shujliaba Formation or liba Group of the Middle Devonian distributed in and around the ore zone.Most of the water of the fluid is meteric and stratigraphic origin.The heat is principaly fromtheZhong chuan granite ntrusive.In the co-epistent zone of sufficient stratigraphical water and the strata which contains comparatively rich easily activated ore-forrning metals,the stvuctural movement and magmatic activity make the stratigraphical water hot in the presence of heat action and then desolve the activated ore-forming metals . Then the fluid keeps on penetrating and migrating until the ore is formed by the concentration at favourable locations .The formation of the ore -bearing hydrothermal fluid has under gone some phases:rainfall,normally -temperatured stratigraphical water ,hypothermal fluid ,and hypothermal ore -bearing brine.The hydrothermal fluid,therefore,is highly-femperatured water solution rich in ore constituents.It is constituted of three key elements :ore constituents,water,and heat .