福建建瓯奖坑银矿床地质特征及成因分析

Geological Characteristics and Cause Analysis of Jiangkeng Siliver Deposit in Jian'ou City,Fujian Province

建瓯奖坑银矿位于华夏地块北武夷隆起区东部,政和—大埔断裂带西缘,银矿体主要贮存于作为推覆构造外来岩块的印支期花岗岩中,明显受区内逆冲断层及其派生的推覆体内的北西西向断裂、裂隙带控制。矿体呈脉状、透镜状产出,多为隐伏矿体。围岩蚀变主要有硅化、绢云母化、绿泥石化等。通过对矿区成矿地质背景、矿床地质特征、流体包裹体物理性质、氢-氧同位素和S同位素特征研究,初步认为矿床成矿物质主要来自深源,成矿流体主要为岩浆水和大气降水的混合水,矿床成因类型为中低温热液型银矿床。

Jiangkeng silver deposit in Jiang'ou city is located in the east of North Wuyi uplift of Cathaysia block and on the west edge of Zhenghe-Dapu fault zone.The silver ore bodies are mainly stored in indosinian granite,which is an extraneous block of nappe structure,and are obviously controlled by nw trending fault and fracture zone of thrust fault and derived nappe body in the area.The ore bodies are pulse shape,lens shape output,and mostly hidden ore body.The alteration of surrounding rock mainly includes silicate,silicite,chloridionization,etc.Based on the study of metallogenic geological background,geological characteristics of the deposit,physical properties of fluid inclusions,hydrogen oxygen isotope and S isotope characteristics,the preliminary conclusion is that the ore-forming materials of the deposit are mainly from deep source,the ore-forming fluid is mainly mixed water of magmatic water and meteoric water,and the genetic type of the deposit is middle-low temperature hydrothermal silver deposit.