腾冲地块那俄铍矿床成矿时代和流体包裹体特征  

Mineralization timing and fluid inclusion characteristics of Na'e beryllium deposit in the Tengchong block

作　　者：明添学 何小虎 唐忠 陈雷 杨清标 薛戈 王云晓 苏肖宇 MING Tianxue;HE Xiaohu;TANG Zhong;CHEN Lei;YANG Qingbiao;XUE Ge;WANG Yunxiao;SU Xiaoyu(Institute of Yunnan Geology Survey(Institute of Yunnan Geological Sciences),Kunming,Yunnan 650051,China;Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization Ministry of Natural and Resources,Kunming,Yunnan 650051,China;Yunnan Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,Ministry of Natural Resources,Kunming,Yunnan 650051,China;School of Earth Sciences,Yunnan University,Kunming,Yunnan 650500,China;Yunnan International Joint Laboratory of Critical Mineral Resource,Kunming,Yunnan 650500,China;Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650093,China;Yunnan Geological Survey Fundation Management Center,Kunming,Yunnan 650224,China)

机构地区：[1]云南省地质调查院(云南省地质科学研究院),云南昆明650051 [2]自然资源部三江成矿作用及资源勘查利用重点实验室,云南昆明650051 [3]云南省三江成矿作用及资源勘查利用重点实验室,云南昆明650051 [4]云南大学地球科学学院,云南昆明650500 [5]云南省关键矿产成矿过程和机制国际联合实验室,云南昆明650500 [6]昆明理工大学国土资源工程学院,云南昆明650093 [7]云南省地质勘查基金管理中心,云南昆明650224

出　　处：《地质学报》2025年第4期1238-1255,共18页Acta Geologica Sinica

基　　金：云南省地质勘查基金项目(编号D202101、D202305、Y202305);云南省兴滇英才计划项目(编号C6213001155)联合资助的成果。

摘　　要：铍(Be)广泛应用于国防尖端科技和战略新兴领域,是一种国家亟需的战略性资源。寻找铍的潜力资源区是快速解决我国铍资源困境的“捷径”。腾冲地块是东特提斯构造域的重要组成部分,经历了复杂的地质构造过程,其中早白垩世—新生代以来岩浆活动频繁,发育大量与岩浆作用相关的锡(钨)稀有金属矿床(点)。地质调查评价表明该区域可能形成潜在的铍、铷、铌、钽等稀有金属矿床,那俄铍矿床是其中发育的典型花岗伟晶岩型矿床,含矿花岗伟晶岩侵入到早白垩世二长花岗岩围岩中。本文通对花岗伟晶岩和二长花岗岩围岩开展锆石U-Pb年代学,并对花岗伟晶岩中绿柱石和石英开展流体包裹体研究,从而探讨那俄铍矿床成矿年代及成矿物理化学条件。LA-ICP-MS锆石U-Pb年代学研究显示,那俄地区含绿柱石花岗伟晶岩年龄为46.9~44.3 Ma,二长花岗岩围岩年龄为122.9 Ma,表明那俄铍矿床形成于始新世,二长花岗岩围岩形成于早白垩世,两者不存在成因关联。结合腾冲地块岩浆活动和构造演化历史,我们认为那俄铍矿床可能是印度-欧亚板块碰撞后构造背景下地壳物质熔融的产物,为典型的造山期后LCT伟晶岩型铍矿床。绿柱石和石英中流体包裹体特征显示,那俄铍矿床中主要发育气液两相NaCl-H_(2)O包裹体以及少量纯液相水包裹体、CO_(2)包裹体,成矿流体具有中低温(172.0~299.4℃)、低盐度(0.70%~3.87%NaCleq)、低密度(0.723~0.913 g/cm^(3))的特征。成矿流体压力和深度估算,表明那俄铍矿床形成于浅层低压环境。腾冲地块锂铍地球化学异常中心与腾冲地块主要锡矿化、伟晶岩带分布一致,暗示腾冲地块稀有金属成矿作用与锡矿化、伟晶岩带关系密切。结合区域已发现铌钽、铷、锂等矿化点,表明腾冲地块存在较大的稀有金属成矿潜力。该研究结果对理解那俄铍矿床的成因和地质背景提供Beryllium(Be) is widely used in advanced science,technology,and emerging strategic fields,making it a vital strategic resource for our country.Exploring potential beryllium resource areas offers a promising solution to China's beryllium resource shortage.The Tengchong block,characterized by complex geological processes,is an important part of the East Tethys tectonic domain.Extensive magmatic activities spanning the Early Cretaceous to the Cenozoic have resulted inthe formation of numerous tin(tungsten)-rare metal deposits in this block.Geological survey and evaluation suggest the potential for beryllium,rubidium,niobium,and tantalum rare-metal deposits in this area.The Na'e beryllium deposit,a typical granitic pegmatite-type deposit,is discovered in the Tengchong block.The rare-metal mineralized granitic pegmatite intruded into wall rocks comprisedof Early Cretaceous monzogranite.This study investigates the zircon U-Pb chronology of the granitic pegmatite,monzogranite(wall rocks),and fluid inclusions in beryl and quartz from the granitic pegmatite to discuss the ore-forming timing and physico-chemical conditions of the Na'e beryllium deposit.LA-ICP-MS zircon U-Pb dating yielded ages of 44.3~46.9 Ma for the beryl-bearing granitic pegmatite,whereas the monzogranite yielded an age of 122.9 Ma.This indicates that the Na'e beryllium deposit formed during the Eocene,whereas the monzogranite(wall rock) formed in the Early Cretaceous.Consequently,we suggest that there is no genetic relationship between the granitic pegmatite and the monzogranite.Combined with the magmatic activities and tectonic evolution of the Tengchong block,we suggest that the Na'e beryllium deposit may be the result of crustal melting in a post-collisional setting caused by the convergence of the Indian and Eurasian plates.It represents a typical LCT pegmatite beryllium deposit formed during a post-orogenic stage.Beryl and quartz from the Na'e beryllium deposit contain vapor-liquid two-phase(NaCl-H_2O) inclusions,with a few pure liquid-phase water

关 键 词：腾冲地块 始新世 花岗伟晶岩 铍矿床 稀有金属 成矿时代 流体包裹体 

分 类 号：P618.7[天文地球—矿床学]