滇西北普朗铜矿首采区北段辉钼矿Re-Os同位素定年及其地质意义  

Re-Os geochronology and implications of molybdenite from the north section of the first mining area of the Pulang copper deposit,NW Yunnan

作　　者：孔垂爱 舒华伟 沙有财 陈明勇 董桥峰 唐思宇 冷开杰 李莹 KONG Chuiai;SHU Huawei;SHA Youcai;CHEN Mingyong;DONG Qiaofeng;TANG Siyu;LENG Kaijie;LI Ying(Yunnan Diqing Nonferrous Metals Co.,Ltd.,Shangri-La 674400,China;Kunming Institute of Exploration and Design,China Nonferrous Industry Company Ltd.,Kunming 650051,China)

机构地区：[1]云南迪庆有色金属有限责任公司,云南香格里拉650093 [2]中国有色金属工业昆明勘察设计研究院有限公司,云南昆明650051

出　　处：《沉积与特提斯地质》2025年第1期200-211,共12页Sedimentary Geology and Tethyan Geology

基　　金：云南迪庆有色金属有限责任公司重点科技创新项目(DQYS202206)。

摘　　要：普朗铜矿是三江特提斯造山带格咱矿集区内最大的印支期斑岩型Cu-Mo多金属矿床。该矿床首采区北段是矿山的重要资源储备区,其成矿特征与首采区相比具有较大差异。首采区北段与首采区是否为同一岩浆活动的产物尚不清楚,这就限制了其与首采区矿化关系的深入探讨以及对成矿规律的总体认识。本次研究对首采区20线以北的矿石辉钼矿进行了ReOs同位素年代学研究,以期为北部区域成矿规律及资源前景的进一步探索和评价提供基础地质资料,从而指导下步补充勘探工作。结果表明,辉钼矿Re-Os同位素加权平均模式年龄为(202.35±0.84)Ma,等时线年龄为(200.7±9.2)Ma,略晚于首采区矿体的形成时代。普朗南部Ⅰ号复式岩体中成矿事件经历了较长的时间(约20 Myr),或许与成矿流体多次幕式活动有关,表明普朗首采区北段具有较大的资源潜力。普朗铜矿矿石样品中辉钼矿Re含量为1.50×10^(-4)~4.45×10^(-4),平均为2.64×10^(-4),暗示成矿物质主要来源于地幔。成矿背景为甘孜–理塘洋向西平坦俯冲于义敦岛弧带南段格咱地区导致大洋板块部分熔融,并诱发大量的埃达克质岩浆的上涌而成矿。The Pulang Cu deposit,located in the Gezan ore-concentrated area of the Sanjiang Tethyan belt,is the largest porphyry Cu-Mo polymetallic deposit formed during the Indosinian orogeny.The north section of the first mining area is a key resource area of the deposit,but its metallogenic characteristics are quite different from those of the first mining area.It remains unclear whether the first mining area and its northern section are products of the same genetic magmatic activity,limiting the in-depth exploration of its relationship with the mineralization of the first mining area and the general understanding of the metallogenic law.In this study,we present new Re-Os geochronology of molybdenite from this section,aiming to provide basic geological data for further exploration and evaluation of metallogenic regularity and resource prospects in the northern region,and to guide further exploration efforts.The molybdenite Re-Os data yield a weighted mean model age of(202.35±0.84)Ma and an isochron age of(200.7±9.2)Ma,slightly younger than the orebody in the first mining area.The mineralization in the No.Ⅰcomposite intrusion in the south zone of Pulang spanned a long period(ca.20 Myr),possibly related to multiple pulses of ore fluids,suggesting a high potential for undiscovered resources in the north section of the first mining area.The Re content of molybdenite ranges from 1.50×10^(-4) to 4.45×10^(-4),with an average of 2.64×10^(-4),indicating a mantle-derived ore-forming materials.The tectonic setting for mineralization was the flat subduction of the Ganzi-Litang ocean beneath the Yidun arc in the southern Gezan area,which triggered partial melting of the oceanic crust and generated voluminous adakitic magmas and associated ore fluids.

关 键 词：RE-OS同位素 成矿年龄 普朗 斑岩矿床 格咱矿集区 

分 类 号：P624[天文地球—地质矿产勘探]