中国地质
中國地質
중국지질
CHINESE GEOLOGY
2015年
1期
235-247
,共13页
闪锌矿Rb-Sr定年%等时线年龄%成矿时代%凹子岗锌矿床
閃鋅礦Rb-Sr定年%等時線年齡%成礦時代%凹子崗鋅礦床
섬자광Rb-Sr정년%등시선년령%성광시대%요자강자광상
sphalerite Rb-Sr dating%isochron age%metallogenic epoch%Aozigang zinc deposit
提凹子岗锌矿床位于黄陵背斜东部,是近年来在湘西鄂西地区发现的代表性矿床。锌矿体呈似层状-透镜状产出,赋存于灯影组二段,含矿岩性为一套角砾状泥粉晶云岩,严格受地层层位及岩性控制。文章运用闪锌矿Rb-Sr同位素测年方法,测得凹子岗锌矿床成矿年龄为431~434 Ma,相当于早志留世,代表了矿床的主成矿阶段年龄。闪锌矿具有较高的Sr同位素初始比值(0.71119~0.71136),反映成矿物质或成矿流体由基底岩石和震旦系碳酸盐岩地层共同提供。凹子岗锌矿床早期成矿作用与早志留世的裂谷盆地伸展运动关系密切,晚期成矿作用与加里东运动关系密切,是伸展环境盆地流体运移的产物。加里期运动与黄陵周缘铅锌矿的成矿作用关系密切。凹子岗锌矿床成因类型为热液喀斯特成因,可分为深埋藏成岩成矿阶段和热液喀斯特化成矿阶段。
提凹子崗鋅礦床位于黃陵揹斜東部,是近年來在湘西鄂西地區髮現的代錶性礦床。鋅礦體呈似層狀-透鏡狀產齣,賦存于燈影組二段,含礦巖性為一套角礫狀泥粉晶雲巖,嚴格受地層層位及巖性控製。文章運用閃鋅礦Rb-Sr同位素測年方法,測得凹子崗鋅礦床成礦年齡為431~434 Ma,相噹于早誌留世,代錶瞭礦床的主成礦階段年齡。閃鋅礦具有較高的Sr同位素初始比值(0.71119~0.71136),反映成礦物質或成礦流體由基底巖石和震旦繫碳痠鹽巖地層共同提供。凹子崗鋅礦床早期成礦作用與早誌留世的裂穀盆地伸展運動關繫密切,晚期成礦作用與加裏東運動關繫密切,是伸展環境盆地流體運移的產物。加裏期運動與黃陵週緣鉛鋅礦的成礦作用關繫密切。凹子崗鋅礦床成因類型為熱液喀斯特成因,可分為深埋藏成巖成礦階段和熱液喀斯特化成礦階段。
제요자강자광상위우황릉배사동부,시근년래재상서악서지구발현적대표성광상。자광체정사층상-투경상산출,부존우등영조이단,함광암성위일투각력상니분정운암,엄격수지층층위급암성공제。문장운용섬자광Rb-Sr동위소측년방법,측득요자강자광상성광년령위431~434 Ma,상당우조지류세,대표료광상적주성광계단년령。섬자광구유교고적Sr동위소초시비치(0.71119~0.71136),반영성광물질혹성광류체유기저암석화진단계탄산염암지층공동제공。요자강자광상조기성광작용여조지류세적렬곡분지신전운동관계밀절,만기성광작용여가리동운동관계밀절,시신전배경분지류체운이적산물。가리기운동여황릉주연연자광적성광작용관계밀절。요자강자광상성인류형위열액객사특성인,가분위심매장성암성광계단화열액객사특화성광계단。
The Aozigang zinc deposit lies in eastern Huangling anticline. It is a representative lead zinc deposit recently discovered in western Hubei and Hunan area. The zinc orebodies are strictly controlled by the stratigraphic horizon and lithology, and are mainly hosted in the second member of the Sinian Dengying Formation. The ore-bearing rocks occur in stratoid and lenticular forms, being a suite of brecciform micritic crystal powder dolomites. The Rb-Sr dating of sphalerite separates yielded isochron ages of 431-434 Ma for the deposit, suggesting that the deposit was formed in the early Silurian, which represents the main ore-forming epoch of the deposit. Based on a study of the source of the ore-forming material and the geological significance, the authors hold that higher initial ratios of Sr isotope (0.71119-0.71136) suggest that the metallogenic substances or ore-forming fluids came from relatively high basement rocks and relatively low Sinian carbonate layers. The early mineralization of the Aozigang zinc deposit was
<br> closely related to the Early Silurian stretching rift basin, whereas the late mineralization was closely associated with the Caledonian movement and was the product of fluid migration in a stretching basin. The mineralization of the lead-zinc deposits around the Huangling faulted dome was closely related to Caledonian movement. The Aozigang zinc deposit is genetically of hydrothermal karst type, and its formation can be divided into deep burial diagenetic ore-forming stage and hydrothermal karst metallogenic stage.