青海卡而却卡铜多金属矿床蚀变矿化类型及矽卡岩矿物学特征  

Mineralization and Alteration Types and Skarn Mineralogy of Kaerqueka Copper Polymetallic Deposit in Qinghai Province

作　　者：李大新[1] 丰成友[1] 赵一鸣[1] 李泽峰 刘建楠[1] 肖晔[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]青海省第三地质矿产勘查院,西宁810029

出　　处：《吉林大学学报（地球科学版）》2011年第6期1818-1830,共13页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局地质调查项目(1212011085528);国土资源部百名优秀青年科技人才计划项目(200809);中央级公益性科研院所基本科研业务费专项资金项目(K0901);中国博士后科学基金项目(20090460132);'十一.五'国家科技支撑计划课题(2006BAB01A06)

摘　　要：卡而却卡铜多金属矿床是柴达木盆地南缘西段祁漫塔格地区颇具特色的一个破碎蚀变带热液脉状-矽卡岩型矿床。矿区内可见2类围岩蚀变:矽卡岩化和黄铁绢英岩化。前者由印支期似斑状黑云母二长花岗岩侵位引起,在岩体侵入接触面及外接触带围岩的不同岩性界面、构造破碎薄弱带形成含铜多金属矽卡岩透镜体,由透辉石、钙铁辉石、钙铁(铝)榴石、符山石、硅灰石、方柱石和阳起石等一套十分典型的钙矽卡岩矿物组成;后者在矿区西北部的似斑状黑云母二长花岗岩体中形成多条呈NWW向平行展布的黄铜矿化热液蚀变带,构成断裂破碎带控制的细(网)脉浸染状热液脉型矿化。研究认为:卡而却卡铜多金属矿床的形成与印支期侵位、具有浅成和高侵位特点的似斑状黑云母二长花岗岩关系密切,产出的矽卡岩型铜多金属矿与破碎蚀变带控制的细(网)脉浸染状热液脉型铜矿的成岩成矿年龄基本一致,其构造-岩浆活动背景相同,但属不同阶段、不同深度和不同部位发生成矿作用的产物,形成以接触带(或外接触带)矽卡岩型铜多金属矿为主体的、成矿母岩体内的构造断裂发育部位伴有热液脉状铜矿化的复合型矿床。Located in Qimantage area of southwest Qaidam basin,Kaerqueka copper polymetallic deposit is a characteristic hydrothermal vein-skarn ore deposit controlled by the fractured and altered zone.Two kinds of wall-rock alterations can be recognized in the ore deposit,i.e.,skarn and phyllic alteration.The former was formed by intrusion of Indosinian porphyaceous biotite adamellite.Copper polymetallic skarn lenticular bodies are commonly seen in the contact zone of the intrusion,different lithologic interfaces and faulted structural zones of the surrounding rocks.There are some typical calcium skarn minerals,such as diopside,hedenbergite,andradite,hessonite,idocrase,wollastonite,epidote,scapolite and actinolite.The latter forms many parallel NWW-striking chacopyritized hydrothermal alteration zones in porphyaceous biotite adamellite in the northwest part of the ore district,belonging to hydrothermal vein type mineralization controlled by faulted fractured zones.It is concluded that Kaerqueka copper polymetallic deposit is related to Indosinian hypabyssal and high emplacement porphyaceous biotite adamellite.The ages of rocks and ores in the copper polymetallic skarn deposit and the veinlet-disseminated hydrothermal veinlike copper deposit are the same,and the backgrounds of tectono-magmatic activities are identical;nevertheless,they are products of different ore-forming processes that occurred at different stages,different depths and different parts.This ore deposit is a compound one,with the skarn copper polymetallic mineralization as the main body,accompanied by the hydrothermal vein type copper mineralization in well-developed faults of the parent rock.

关 键 词：矿化蚀变类型 蚀变分带 矽卡岩矿物学 卡而却卡 青海祁漫塔格 东昆仑 矿床 

分 类 号：P618.41[天文地球—矿床学]