湘中矿集区杨家山石英脉白钨矿床的白云母^(40)Ar-^(39)Ar和LA-ICP-MS锡石U-Pb年龄及其地质意义  

Muscovite ^(40)Ar-^(39)Ar and LA-ICP-MS cassiterite U-Pb dating of Yangjiashan quartz scheelite deposit,Xiangzhong ore district and its geological significance

作　　者：张志远 谢桂青[2] 李伟[3] ZHANG ZhiYuan;XIE GuiQing;HI Wei(Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shiyiazhuang 050031,China;Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China;MNR Key Laboratory of Metallogeny and M ineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]河北地质大学,河北省战略性关键矿产资源重点实验室,石家庄050031 [2]中国地质大学科学研究院,北京100083 [3]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037

出　　处：《岩石学报》2021年第3期794-804,共11页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(42002094、41925011);科技部“973”计划(2014CB440902)联合资助。

摘　　要：杨家山中型石英脉型白钨矿床位于华南湘中低温锑金钨矿集区。白钨矿石英脉产于晚泥盆世黑云母二长花岗岩和新元古界板岩中,是全球为数不多的与花岗岩有关的石英脉白钨矿床,其成矿机制还不清楚。本文开展了与白钨矿共生的锡石的LA-ICP-MS微区原位U-Pb同位素测年,获得206Pb/238U加权平均年龄值为410.4±5.7Ma(MSWD=1.5,n=24)。同时,获得了与白钨矿共生的白云母的^(40)Ar-^(39)Ar同位素坪年龄为395.4±3.2Ma,等时线年龄398.2±4.4Ma,这些定年结果暗示杨家山钨矿床形成于晚泥盆世,与黑云母二长花岗岩的成岩时代在误差范围内一致。结合前人的年代成果,暗示湘中矿集区发育一期晚泥盆世的钨金成矿事件。通过以上研究,不仅能深化湘中矿集区钨金矿床的成矿规律认识,而且可以为找矿勘查取得突破提供重要的理论支撑。Yangjiashan scheelite deposit is a quartz vein type one hosted in Late Devonian biotite monzogranite that intruded in the surrounding Neoproterozoic slate in the Xiangzhong low-temperature Sb-Au-W ore district,South China.It is one of the few graniterelated quartz vein scheelite deposits in the world,and its ore-forming mechanism is still unclear.This paper reported the U-Pb isotope dating of cassiterite by the method of in-situ LA-ICP-MS from Yangjigshan tungsten deposit.Cassiterite coexisting with scheelite yields a weighted mean206 Pb/238 U age of 410.4±5.7 Ma(MSWD=1.5,n=24).Muscovite associated with scheelite yielded a ^(40)Ar-^(39)Ar plateau age of 395.4±3.2 Ma,with an isochron age of 398.2±4.4 Ma.We infer that Yangjiashan tungsten deposit was formed in the Late Devonian,which is consistent with the zircon U-Pb ages of the biotite monzogranite within analytical uncertainties.Combined with previous ages in the literature,it is suggested that a Late Devonian W-Au metallogenic event developed in the Xiangzhong ore district.The above research results not only deepen the understanding of metallogenic theory of tungsten gold deposits in Xiangzhong ore district,but also provide important theoretical support for the breakthrough of prospecting and exploration.

关 键 词：白云母40Ar-39Ar同位素年龄 锡石LA-ICP-MS U-Pb年龄 杨家山钨矿床 湘中矿集区 华南 

分 类 号：P618.67[天文地球—矿床学]