藏南多层位金锑含矿建造特征及其控矿因素制约

初步研究表明,成矿带内主要矿床(点)的赋矿地层具有明显的规律性特征,发育时代和藏南印支和燕山两期伸展运动的构造背景相对应。含矿沉积建造可基本分为碎屑岩型和硅质岩型两类,分别代表裂陷(谷)盆地内的浊流或喷流沉积相。深部来源的矿质可能是产生区域性成矿作用的主要矿源,而地层来源的Au、Sb则起辅助作用。变质核杂岩的空间结构以及拆离构造的发育型式和含矿建造关系密切,它们往往构成有利的容矿和导矿构造。此外,喜山期岩浆活动和含矿建造的发育也存在时空耦合关系。

CHARACTERISTICS OF MULTI- HORIZON ORE- BEARING FORMATIONS IN SOUTHERN TIBET AU- SB METALLOGENIC BELT AND ITS CONTROLLING FACTORS

The Southern Tibet Au - Sb metallogenic belt is an important region for the metallogenic study in the continental collision zone, and it is also a significant area for the distribution of the Au - Sb deposits in our country.Our preliminary study reveals that the ore - bearing strata were mainly found in the upper Triassic, lower Jurassic,upper Jurassic - lower Cretaceous, and their occurrences can properly correspond to the background of the Indosinian and Yanshanian extensional movements. Based on the kinds of the hosted rocks, the ore - bearing formation can be divided into the clastic rock type and the siliceous rock type, which represent the turbidite facies and the exhalative facies, respectively. The analysis of the ore - controlling factors indicates that the metallogenic metals probably were mainly derived from the deep source while partly from the strata. Both the spatial structure of the metamorphic core complexes and the characteristics of the detachment faults are closely associated with the metallogenic process,and they serve as the passageways for ore fluid and host structures. Additionally, the age of the metallogenic process was closely related to the magmatism in Himalayan epoch, which suggests that the magmatism is also a key factor that affects the metallogenic process, this is simply because that it can serve to provide the heat energy needed for driving the ore -bearing fluids from the deep and settling them down in the shallow crust.