八庙-青山金红石矿床锆石年代学和地球化学研究  

Zircon geochronological and geochemical studies on Bamiao-Qingshan rutile deposit

作　　者：孟洁 李厚民[3] 李立兴[3] 宋哲 MENG Jie;LI HouMin;LI LiXing;SONG Zhe(Development and Research Center of China Geological Survey,Beijing 100037,China;China University of Geosciences,Beijing 100083,China;MNR Key Laboratory of Metallogeny and Mineral Resources Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;Faulty of Earth Resources,China University of Geosciences,Wuhan 430074,Hubei,China)

机构地区：[1]中国地质调查局发展研究中心,北京100037 [2]中国地质大学,北京100083 [3]自然资源部成矿作用与资源评价重点实验室中国地质科学院矿产资源研究所,北京100037

出　　处：《矿床地质》2018年第5期961-984,共24页Mineral Deposits

基　　金：国家自然科学基金项目（编号：41402067、41672078）;中国地质调查局中国矿产地质与成矿规律综合集成和服务（矿产地质志）项目（编号：DD20160346）的联合资助

摘　　要：八庙-青山金红石矿床位于豫、陕两省交界处的西峡县与商南县之间,大地构造位置处于南秦岭地块的北缘。矿体呈层状、透镜状赋存于一套低角闪岩相变质的基性火山岩内,矿化层与大理岩互层产出。目前对于其含矿岩系的时代归属问题尚有中新元古代与中晚古生代之争。锆石年代学分析结果显示八庙矿区含矿岩系的底板围岩含石榴子石二云石英片岩主要包含3个阶段的年龄,即2664～1373 Ma、1003～874 Ma和468～411 Ma,青山矿区的含金红石斜长角闪片岩主要包含4个阶段的年龄,即1860～1441 Ma、1103～969 Ma、832～780 Ma和433～418 Ma。2个样品的最小锆石年龄数据一致,且与前人在含矿岩系大理岩中发现的古生物化石指示的时代相近。因此,八庙-青山金红石矿床的赋矿地层时代应归属于早泥盆世。全岩地球化学分析结果表明含矿岩石具洋岛玄武岩特征,源区可能为石榴橄榄岩,指示高钛的岩浆物质来自深部地幔。The Bamiao-Qingshan rutile deposit is located between Xixia and Shangnan County which is at the border of Henan and Shaanxi Province, and distributed along the northern margin of the southern Qinling Block. The rutile orebody occurs layered, lenticular, hosted in a series of low-amphibolite facies metamorphosed mafic volca- nic rocks and the rutile-bearing layers are interlayered with the marbles. Recently, the forming age of the rutile- bearing rocks remains disputed in Middle-Late Proterozoic or Middle-Late Paleozoic. Zircon dating results show that the garnet-bearing two-mica-quartz schist, which is distributed at the floor of the rutile-bearing rock series in the Bamiao area, covers the ages of 2664-1373 Ma, 1003-874 Ma and 468-411 Ma, while the rutile-bearing pla- gioclase-hornblende schist in the Qingshan area contains the ages of 1860-1441 Ma, 969-1103 Ma, 780-832 Ma and 433-418 Ma. The youngest zircon ages of both samples show similar and consistent with the stratigraphic age of Palaeontological fossil indicators which was discovered in the interlayered marble of the ore-bearing rock series. Therefore, the ore-hosted stratigraphic age of the Bamiao-Qingshan rutile deposit should be attributed to Early Devonian. Whole-rock geochemical analysis reveal that the rutile-bearing rocks show the characteristics of oceanic island basalt, indicating the high-Ti magmatic material came from deep mantle.

关 键 词：地球化学 金红石矿床 锆石U-PB测年 八庙-青山矿床 

分 类 号：P597.3[天文地球—地球化学] P595[天文地球—地质学]