CAJ | 학술논문

内蒙古白乃庙铜矿床位于中亚造山带温都尔庙加里东增生带铜多金属成矿带，矿床包括南、北两个矿带，南矿带矿体产于白乃庙组绿片岩中，北矿带矿体主要产于加里东期花岗闪长斑岩体内。成矿作用大致分为早、中、晚3个阶段，分别以石英－黄铁矿，石英－黄铜矿、辉钼矿，石英、方解石－方铅矿、闪锌矿组合为标志。同位素测试结果显示：石英流体包裹体中的δ18 OH2O值在－3.2‰～5.5‰之间，δD 变化范围为－94.2‰～－69‰，随着成矿作用的进行，δD 基本不变，δ18 OH2O逐渐降低；热液方解石的δ13 CPDB为－5.4‰～－2.4‰，δ18 OSMOW为－3.1‰～10.9‰，随着成矿作用的进行，δ13 CPDB基本不变，δ18 OSMOW逐渐降低；硫化物的δ34 S 值变化范围为－0.6‰～－6‰，显示出幔源硫的特征。碳、氢、氧、硫同位素显示南、北矿带不同成矿阶段流体主要来自岩浆系统，且南、北矿带间没有明显差异，但南矿带流体显示有更多大气降水和壳源物质的加入。结合矿床地质特征分析，认为在加里东期古洋壳经俯冲作用发生部分熔融形成花岗闪长岩岩浆，并沿着裂隙上升到浅部，带来成矿物质，对原始矿源层的成矿物质进行活化富集，在白乃庙岛弧带形成白乃庙斑岩铜矿床。
내몽고백내묘동광상위우중아조산대온도이묘가리동증생대동다금속성광대，광상포괄남、북량개광대，남광대광체산우백내묘조록편암중，북광대광체주요산우가리동기화강섬장반암체내。성광작용대치분위조、중、만3개계단，분별이석영－황철광，석영－황동광、휘목광，석영、방해석－방연광、섬자광조합위표지。동위소측시결과현시：석영류체포과체중적δ18 OH2O치재－3.2‰～5.5‰지간，δD 변화범위위－94.2‰～－69‰，수착성광작용적진행，δD 기본불변，δ18 OH2O축점강저；열액방해석적δ13 CPDB위－5.4‰～－2.4‰，δ18 OSMOW위－3.1‰～10.9‰，수착성광작용적진행，δ13 CPDB기본불변，δ18 OSMOW축점강저；류화물적δ34 S 치변화범위위－0.6‰～－6‰，현시출만원류적특정。탄、경、양、류동위소현시남、북광대불동성광계단류체주요래자암장계통，차남、북광대간몰유명현차이，단남광대류체현시유경다대기강수화각원물질적가입。결합광상지질특정분석，인위재가리동기고양각경부충작용발생부분용융형성화강섬장암암장，병연착렬극상승도천부，대래성광물질，대원시광원층적성광물질진행활화부집，재백내묘도호대형성백내묘반암동광상。
The Bainaimiao copper deposit in Inner Mongolia is located in the Ondor Sum Caledonian copper polymetallic zone of the Central Asian Orogenic Belt.Copper mineralization in Bainaimiao is comprised of the northern and southern zones.The host rock of the southern zone is greenschist of the Bainaimiao Formation, while orebodies in the northern zone mainly occur in the Caledonian granodiorite porphyry.The metallogenic processes can be divided into early,middle,and late stage,which is characterized by mineral assemblages of quartz-pyrite,quartz-chalcopyrite ±molybdenite,and quartz ±calcite ±galena-sphalerite,respectively.Theδ18 OH 2O and δD values of fluid inclusions in quartz range from -3.2 ‰ to 5.5 ‰ and from -94.2 ‰ to-69 ‰,respectively.The δD values are relatively constant,whereas the δ18 OH 2O values decrease gradually from early to late stage.In addition,the δ13 CPDB and δ18 OSMOW values of hydrothermal carbonate minerals range from -5.4 ‰ to -2.4 ‰ and from -3.1 ‰ to 10.9 ‰,respectively.The δ13 CPDB values keep steady,and the δ18 OSMOW values reduce gradually during the mineralization processes.The δ34 S values of the sulfides range from -0.6 ‰ to -6 ‰ and are typical of mantle source.The C-H-O-S isotopic compositions of the southern and northern zones show that ore-forming fluids of different stage are mainly derived from magma system,and there are no obvious differences between these two zones.However,the fluids in the southern zone exhibit clos-er affinity to meteoric water and crustal substances.Combined with geological features of the deposit,it is con-cluded that the Bainaimiao deposit was produced by granodioritic magma that formed by anatexis under subduc-tion environment,and the magma arose along fissures up to the shallow crust.These processes gave rise to the activation and enrichment of ore metals from source beds of the Bainaimiao strata,and the formation of the Bai-naimiao porphyry copper deposit.