北山区域地质发展史和金矿区域成矿模式

THE GEOLOGICAL DEVELOPMENT AND REGIONAL METALLoGENIC MODEL FOR GOLD OF BEISHAN AREA

本文通过对北山地区地层、岩浆岩宏观和微观特征的详细研究,论证了北山南带是一个发育于前寒武纪古陆上的陆缘裂陷槽,其3次拉张闭合运动控制了古生代的岩浆活动而使其呈现有序的演化。区内的金及与其伴生的亲铜元素矿产与裂陷糟最后闭合所派生的岩浆热液活动有紧密的成因和空间联系,为其演化的端元产物。在研究本区两大金矿类型(含金石英脉和蚀变岩)的物质成分,共生矿物的标型特征和围岩蚀变的基础上,阐明了北山的主要金矿成矿规律,建立了金矿区域成矿模式。

Analyzing the macroscopic and microscopic features of the sedimentary sequences and magmatic rocks developed in Beishan Area. this paper evidences that the southern zone of Beishan was a continental margin aulacogen developed on the basement of Precambrian old continent. The three times of tension-compression of the aulacogen during Paleozoic controlled the magmatism and made it of sequential evolution. Mineralizations of gold and associated chalcophile elements in Beishan Area are closely related to the magmatizm derived from the third (last) compression of the aulacogen in Late Permian and should be regarded as the end of the magma-hydrothermal evolution. On the basis of the careful study on the ore composition, typomorphic characteristics of associated minerals and wall-rock alterations of the two main types of gold mineralization (gold-bearing quartz vein and altered rock type), the basic metallogenic regularities are discussed, and the regional metallogenic model for gold in the area has been established.