广西云开地区金银成矿条件分析  

THE ANALYSIS OF Au-Ag ORE-FORMING CONDITIONS IN YUNKAI AREA,GUANGXI

作　　者：姚建敏[1] 陈尚迪[2] 曹殿春[2] 

机构地区：[1]成都地质矿产研究所,成都610082 [2]成都地质学院应化系,成都610059

出　　处：《南方国土资源》1993年第2期25-38,共14页

基　　金："七五"国家科技攻关项目

摘　　要：广西云开地区系指容县—博白一线以东广西境内地区,包括云开隆起西南部与博白拗陷两个构造单元,面积近11800km^2。它属我国粤西—桂东金银锡铌钽成矿带。区内有金银矿床(点)近70处,受博白—岑溪深断裂带控制,寒武—奥陶系是金银矿主要赋存层位,构造蚀变岩型金银矿床是主要矿床类型。本文在论述该区成矿地质背景基础上,详细地对析了物源、成矿热液、岩浆活动、构造活动与地球化学等成矿条件,认为:区内的寒武—奥陶系是金银的原始矿源岩,在局部地段经过长期地质作用的改造可形成金银再造矿源岩(构造蚀变岩),又是金银矿体定位有利地段;成矿热液是以地下水为主并渗入了大气降水与岩浆水的混合型热液;燕山晚期中酸性岩浆活动是成矿的重要条件:断裂构造交汇处是矿化集中区:指出区内金银矿化主要与寒武—奥陶系、动力变质带和燕山晚期中酸性岩存在时空和成因联系,揭示了成矿具多源、多期和多成因特点,并概括为原始矿源岩→再造矿源岩→矿体的步进递增成矿模式。文后对深化找矿提出三点建议。Yunkai area with an area of 11,800 km2 is referred as to the area east of Rongxian county—— Bobai county within Guangxi, including southwestern Yunkai uplift and Bobai depression. The area belongs to the mineralization belt of Au, Ag, Sn, Nb and Tb along Western Guangdong Province and Eastern Guangxi Province. There are nearly seventy Au/Ag mineral deposits or occurrences in the area which are most hosted in Cambrian and Ordovician Systems and are controlled by Bobai—— Cenxi deep fault zone. And these Au/Ag mineral deposits belong to structural altered type in genesis. On the basis of geological background of mineralization in the area,the paper has in detail analysized the ore -forming conditions such as source material, ore - forming solution , magmatism , tectonism and geochemistry,and has considered that the Cambrian and Ordovician Systems in the area are the source beds for Au/Ag mineral deposits and may be locally transformed into regenerated source beds (structural altered rocks) by endly geological processes, and are also the favourable sections for the orientation of Au orebodies; the ore -forming solution is dominated by groundwater, mingled with meteoric water and magmatic water;the intermediate - acid magmatism in late Yanshanian movement is the important condition for mineralization; the intersections of fractures are the concentration area of mineralization. The paper points out that the Au/Ag mineralization is associated in space- time and genesis with the Cambrian and Ordovician systems, dynamometamorphic belt and late Yanshanian intermediate-acid rocks. The paper also reveals that the mineralization is characterized by multiple sources, stages and geneses, and demonstrates the mineralization model from initial resource beds to regenerated source beds (structural altered beds) and finally to orebodies. At the end, the paper puts forward three suggestions for deepening prospecting.

关 键 词：金银 成矿条件 再造矿源岩 寒武——奥陶系 构造 岩浆岩 广西 

分 类 号：P[天文地球]