摘要
西南三江地区是我国重要的成矿区带之一,具有复合叠加成矿特征。阿德博独居石矿床位于云南省金平县境内,印度地块、哀牢山-金沙江断裂带南侧,属于哀牢山隆起的东南延伸部分。该矿床赋存于花岗质风化壳中,岩性主要有片麻状花岗岩、二长花岗岩、花岗片麻岩;矿体中主要含有独居石,少量磷钇矿、锆石、金红石、钛铁矿、榍石。岩体中片麻状花岗岩的锆石U-Pb谐和年龄为31.40±0.16Ma(MSWD=7.8),二长花岗岩的锆石U-Pb谐和年龄为34.52±0.22 Ma(MSWD=1.3),表明阿德博岩体形成于新生代古近纪,与三江地区构造体制转换阶段富碱斑岩体的成矿时期一致。片麻状花岗岩中45个锆石Hf同位素数据结果较均一,(176Hf/177Hf)i比值范围为0.282583~0.282712,平均为0.282633,εHf(t=31.40 Ma)范围为-6.00^-1.44,平均值为-4.21。二长花岗岩中13个锆石Hf同位素数据结果变化范围较大,(176Hf/177Hf)i=0.282484~0.282814(平均值为0.282681),εHf(t=31.40 Ma)=-9.43~2.22(平均值为-2.45);其中有8粒锆石的εHf(t)为负值,5颗锆石的εHf(t)为正值,暗示岩体的源区主要为地壳物质的部分熔融,可能有地幔物质的混合。
The Sanjiang area in southwest China is one of the most important ore-forming belts,characterized by composite and superimposed metallogenesis.A typical case in this area is the the Adebo monazite deposit of Jinping County,Yunnan Province,which lies in the southern margin of AilaoshanJinshajiang strike-slip fault,part of the southeast extension of the Ailaoshan uplift in the India massif.The deposit is hosted by a granitic weathered crust,composed of gneissic granite,monzogranite and granitic gneiss.The orebody mainly contains monazite,with a small amount of xenotime,zircon,rutile,ilmenite and titanite.The zircon U-Pb concordia ages of gneissic granite and monzogranite are 31.40±0.16 Ma( MSWD = 7.8) and 34.52±0.22 Ma( MSWD = 1.3),respectively,implying that Adebo pluton formed in Paleogene,almost the same period with the metallogenetic stage of alkali-rich porphyry in transition of geodynamic regime in the Sanjiang area.The Hf isotopic data of 45 zircons of gneissic granite have a small range,with(176Hf/177Hf)iratios from 0.282583 to 0.282712( 0.282633 on average),and εHf( t= 31.40 Ma) between-6.00 and-1.44(-4.21 on average).The Hf isotopic data of 13 zircons of monzogranite,however,have a large variation range,with(176Hf/177Hf)iratios from 0. 282484 to 0. 282814( 0. 282681 on average),and εHf( t = 34.52 Ma) between-9.43 and 2.22(-2.45 on average),in which eight data lower than 0 and the other five data higher than 0.These characteristics suggest that the magma source was mainly from the partial melting of crust,and probably mixed with some mantle material.
作者
王炳华
曹晓民
杨淑胜
邢程
孙涛
李婉婷
张爱萍
WANG Binghua;CAO Xiaomin;YANG Shusheng;XING Cheng;SUN Tao;LI Wanting;ZHANG Aiping(Institute of Yunnan Geological Survey(Yunnan Academy of Geoscience),Kunming,Yunnan 650216;School of Resource Environment and Earth Sciences,Yunnan University,Kunming,Yunnan 650091)
出处
《地质与勘探》
CAS
CSCD
北大核心
2020年第3期523-539,共17页
Geology and Exploration
基金
中国地质调查局成都地质调查中心矿产地质调查项目(编号:DD20179604-06、DD20160016-10)资助。
关键词
花岗质风化壳
独居石矿床
阿德博
金平县
云南
西南三江
granitic weathered crust
monazite deposit
Adebo
Jinping County
Yunnan Province
Sanjiang area
