西藏邦铺钼(铜)矿床辉绿玢岩脉体LA-ICP-MS锆石U-Pb定年及其地质意义  

LA-ICP-MS Zircon U-Pb Dating of Allgovite in the Bangpu Molybdenum(Copper) Deposit in Tibet and Its Geological Significance

作　　者：冷秋锋[1] 王立强[2] 应立娟[2] 郑文宝[1] 罗茂澄[3] 陈伟[1] 林彬[1] 王艺云[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610059 [2]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037 [3]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地球学报》2012年第4期559-568,共10页Acta Geoscientica Sinica

基　　金：国家973项目(编号:2011CB403103);青藏专项(编号:1212011085529)联合资助

摘　　要：西藏邦铺斑岩型钼(铜)矿床位于冈底斯成矿带东段,地理位置上与甲玛铜多金属矿床、驱龙斑岩铜矿床毗邻。矿区岩浆活动频繁,发育不同类型、不同期次的侵入岩体,辉绿玢岩出露于矿区北部,地质研究程度相对较低。为了精确限制其成岩时代,文章通过对辉绿玢岩脉体LA-ICP-MS锆石U-Pb年龄精确测试,获得了19颗锆石206Pb/238U加权平均年龄为15.21±0.29Ma(MSWD=9.6,N=19),为冈底斯带中新世岩浆侵位年龄,与区域上邻近的甲玛斑岩矿床辉绿玢岩形成时代基本一致。区域成矿规律研究表明,邦铺斑岩型钼(铜)矿床与甲玛、驱龙等超大型斑岩型矿床的成岩成矿时代具有统一性和集中性,显示该矿床与甲玛、驱龙矿床的形成应具有统一的地球化学动力学背景和相关的深部作用过程。The Bangpu porphyry Mo （Cu） deposit is located in the eastern part of the Gangdise metallogenic belt in Tibet, near the Jiama copper polymetallic deposit and the Qulong porphyry Cu deposit. The magma invasion is of high frequency in this area, and varied kinds of intrusions were developed in different periods. Researches on the allgovite in the northern part of the Bangpu ore district are very insufficient. The age of allgovite was obtained in this deposit. According to LA-ICP-MS analysis of the zircon U-Pb age precision of the allgovite, 19 zircons from allgovite yielded the weighted average ^206pb/^238U age of 15.21±0.29 Ma （MSWD=9.6, N=19）, suggesting Miocene magma emplacement in Gangdise belt, and the age is consistent with that of allgovite in the Jiama porphyry deposit. Regional ore-forming regularity study shows that the Bangpu porphyry Mo （Cu） polymetallic deposit is in accord with the regional porphyry deposits such as Jiama and Qulong in the ore-forming and rock-forming age, suggesting that this deposit has the same geochemical dynamic background deep process as Jiama, Qulong and some other ore deposits.

关 键 词：LA-ICP-MS 锆石U-PB定年 辉绿玢岩 邦铺 冈底斯 西藏 

分 类 号：P588.13[天文地球—岩石学] P597[天文地球—地质学]