摘要
桂东金矿化集中区花岗岩类,可划分为过渡性地壳同熔型和陆壳改造重熔型两个系列。两者具有不同的成矿专属性:同熔型花岗岩与金银成矿有着密切的时空成因关系;重熔型花岗岩对锡钨及铜铅锌成矿具有专属性。同熔型花岗岩随时代演化,分异程度增高酸度增大,在空间上由隆起带中部向边缘迁移变化。构造-岩浆演化严格控制了金银成矿演化,形成一个自加里东至燕山期由金-黄铁矿-石英建造向余银多金属硫化物建造演化的金银成矿系列,并且银的矿化向隆起带边缘逐渐增强。同熔型花岗岩主要受加里东期和印支期北西向断裂带控制,而印支期构造-岩浆活动以形成剪切带蚀变岩型金矿化为其重要特色,是桂东工业金矿床定位的主要成矿期。本区北西向沟造-岩浆带的控矿作用,对指导大瑶山隆起区的进一步找矿有重要意义。
Granitoids in the Au-rich mineralization districts of eastern Guangxi may be divided into the transitionsl syntexis crust type series and the transformation remelting continental crust type series. Both they are characterized by distinet metallogenetic specialization: Syntexis type granites bear a close space-time relationship to gold and silver mineralization relation to tin, tungsten, copper, lead and zinc. The syntexis type granites are on the increase in high differentiation and acididy with their evolution of time and are spatially changed from the central part of the uplifted zone outward. The gold- and silvermineralization evolution is strictly controlled by tectonomagmatic evolution, forming a gold and silver metallogenetic series evolved from the Au-pyrite-quartz formation to the Au-Ag-polymetallic sulfide formation during Caledonian-Yenshanian period. As a result, Ag-mineralization strengthenes gradationally toward the edge of the uplifted zone. Syntexis type granites are largely controlled by Caledonian and Indo-Sinian NW-striking faulted zones. Indo-Sinian tectonomagmation is characterized mainly by shear zone altered-rock type gold mineralization and presents the major mineralization epoch for emplacing gold deposits in eastern Guangxi. The role in controlling mineralization by tectonomagmation in this area is of great importance to guiding the further exploration in the Dayaoshan uplifted area.
关键词
花岗岩
金矿床
银矿床
成矿作用
granitoid
gold deposit
silver deposit
mineralization
Guangzi
