中国有色金属学报
中國有色金屬學報
중국유색금속학보
THE CHINESE JOURNAL OF NONFERROUS METALS
2013年
12期
3518-3528
,共11页
凡口式MVT铅锌矿床%地球化学特征%成矿流体%成矿物质来源%成矿作用过程
凡口式MVT鉛鋅礦床%地毬化學特徵%成礦流體%成礦物質來源%成礦作用過程
범구식MVT연자광상%지구화학특정%성광류체%성광물질래원%성광작용과정
Fankou-type MVT lead-zinc deposit%geochemistry%ore-forming fluid%ore-metal source%metallogenesis
粤北曲仁碳酸盐岩盆地北缘聚集的铅锌硫化物矿床地质矿化特征相比于其他MVT矿床,具有成矿特殊性。为了确定该类矿床成矿流体和物质的来源以及成矿作用过程,对研究区矿床地层、断裂构造地球化学特征、稀土元素、硫铅同位素和流体包裹体特征进行系统研究。结果表明:地层、构造以及稀土元素研究结果显示该类铅锌硫化物矿床经历了黄铁矿矿化与铅锌矿化两个成矿作用过程,前者与赋矿层灰岩的物源联系更紧密,后者的成矿金属物质并非直接来自赋矿层灰岩,而是由通过北东、北西向断裂向上运移的盆地深部流体提供,且局部受到中基性岩浆侵入活动轻微改造;矿石及相关地质体同位素地球化学特征显示铅主要来自盆地基底碎屑岩层,部分来自盆地深部壳源重熔型花岗质岩浆,少部分来自盆地碳酸盐岩层,而硫主要为地层硫,小部分为壳源岩浆硫;闪锌矿流体包裹体气液相成分、盐度和温度结果显示铅锌热液成矿期古地热高异常,盆地基底碎屑岩含水系统及燕山期岩浆热液参与铅锌成矿。综合矿床地球化学特征可知,粤北曲仁盆地北缘凡口式MVT铅锌矿床属于两期热液叠加-改造热液型铅锌矿床。
粵北麯仁碳痠鹽巖盆地北緣聚集的鉛鋅硫化物礦床地質礦化特徵相比于其他MVT礦床,具有成礦特殊性。為瞭確定該類礦床成礦流體和物質的來源以及成礦作用過程,對研究區礦床地層、斷裂構造地毬化學特徵、稀土元素、硫鉛同位素和流體包裹體特徵進行繫統研究。結果錶明:地層、構造以及稀土元素研究結果顯示該類鉛鋅硫化物礦床經歷瞭黃鐵礦礦化與鉛鋅礦化兩箇成礦作用過程,前者與賦礦層灰巖的物源聯繫更緊密,後者的成礦金屬物質併非直接來自賦礦層灰巖,而是由通過北東、北西嚮斷裂嚮上運移的盆地深部流體提供,且跼部受到中基性巖漿侵入活動輕微改造;礦石及相關地質體同位素地毬化學特徵顯示鉛主要來自盆地基底碎屑巖層,部分來自盆地深部殼源重鎔型花崗質巖漿,少部分來自盆地碳痠鹽巖層,而硫主要為地層硫,小部分為殼源巖漿硫;閃鋅礦流體包裹體氣液相成分、鹽度和溫度結果顯示鉛鋅熱液成礦期古地熱高異常,盆地基底碎屑巖含水繫統及燕山期巖漿熱液參與鉛鋅成礦。綜閤礦床地毬化學特徵可知,粵北麯仁盆地北緣凡口式MVT鉛鋅礦床屬于兩期熱液疊加-改造熱液型鉛鋅礦床。
월북곡인탄산염암분지북연취집적연자류화물광상지질광화특정상비우기타MVT광상,구유성광특수성。위료학정해류광상성광류체화물질적래원이급성광작용과정,대연구구광상지층、단렬구조지구화학특정、희토원소、류연동위소화류체포과체특정진행계통연구。결과표명:지층、구조이급희토원소연구결과현시해류연자류화물광상경력료황철광광화여연자광화량개성광작용과정,전자여부광층회암적물원련계경긴밀,후자적성광금속물질병비직접래자부광층회암,이시유통과북동、북서향단렬향상운이적분지심부류체제공,차국부수도중기성암장침입활동경미개조;광석급상관지질체동위소지구화학특정현시연주요래자분지기저쇄설암층,부분래자분지심부각원중용형화강질암장,소부분래자분지탄산염암층,이류주요위지층류,소부분위각원암장류;섬자광류체포과체기액상성분、염도화온도결과현시연자열액성광기고지열고이상,분지기저쇄설암함수계통급연산기암장열액삼여연자성광。종합광상지구화학특정가지,월북곡인분지북연범구식MVT연자광상속우량기열액첩가-개조열액형연자광상。
Compared with other MVT deposits, the lead-zinc sulfide deposits gathering in the north margin of Quren carbonate basin, Guangdong Province, China, have mineralization particularity. The deposit strata and fault structure geochemistry, rare earth elements (REE), sulphur isotope, lead isotope and fluid inclusion geochemistry were discussed for understanding the source of the ore-forming metal, fluids and the mineralization processes in Fankou-type lead-zinc deposit. The strata, fault structure and REE results show that this type deposit experiences pyrite and lead-zinc mineralization processes, the former gets closer provenance contact with limestone, while ore metal of the latter does not come directly from ore-hosting carbonate rocks, but gets from basin deep fluid transferred up by NE, NW faults, and is slightly modified by intermediate-basic magmatism. Lead and sulphur isotope geochemistry of ores and related geological samples shows that lead comes mainly from basement clastic formation, partly from crust remelting type granitic magma, little from carbonate rocks;sulphur is mainly from carbonate rocks, only a litter from crustal magma.Sphalerite fluid inclusions components, salinity and temperature results reveal that lead-zinc hydrothermal mineralization exists ancient geothermal anomaly, and basement clastic aquifer and Yanshanian granite are involved in lead-zinc mineralization. Fankou-type MVT lead-zinc deposit in this research area can be classified as two-hydrothermal superimposition-transformation lead-zinc deposit after geochemical characteristics of ore deposits being analyzed synthetically.