云南东川播卡金矿床成因探讨  

Discussion on the Genesis of Boka Gold Deposit in Dongchuan,Yunnan Province

作　　者：黄超文[1,2] 张术根[1,2] 刘纯波[1,2] 莫京龙 李凯林[1,2] HUANG Chaowen ZHANG Shugen LIU Chunbo MO Jinglong LI Kailin(Key Laboratory of Metallogenic Prediction of Nonferrous Metals,Ministry of Education,Central South University, Changsha 410083, Hunan, China School of Geoscience and lnfo-Physics, Central South University, Changsha 410083, Hunan, China)

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,湖南长沙410083 [2]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《黄金科学技术》2016年第6期49-56,共8页Gold Science and Technology

摘　　要：东川播卡金矿床产于古—中元古界浅变质火山碎屑沉积岩和碎屑碳酸盐岩建造中。含金黄铁矿的δ34(V-CDT)值变化范围为3.71‰~7.93‰,说明岩浆源区和地层源区硫在成矿热液系统中高度混合均匀化。流体包裹体均一温度范围为130~260℃,具双峰特征,显示中温热液两阶段演化特征。包裹体盐度集中于13.5%~17.6%,说明成矿热液为中高盐度流体。包裹体气相成分以H_2O为主,含少量CO_2、CH_4和H_2;液相成分阴离子(团)主要为F^-、Cl^-和SO_4^(2-),阳离子成分主要为Na^+、K^+、Ca^(2+)和Mg^(2+)。区内金矿床在热液成矿期后,明显存在动力变质成矿期。热液成矿时代为印支—燕山早期,为岩石圈膨胀动力背景下与印支—燕山早期钠质闪长岩类岩浆活动有关的混合热液成矿作用形成矿床后,经喜马拉雅期脆—韧性剪切作用发生动力变质改造而最终形成的多因复成矿床。Boka gold deposit is hosted in a set of low-grade metamorphic pyroclastic sedimentary rocks and detrital carbonatite in the Paleoproterozoic-Mesoproterozoic.The δ34（V-CDT） of gold-bearing pyrite has a change rangefrom 3.71%-7.93%o ,which suggests that the sulfur comes from magma and stratums have been blend very wellin the hydrothermal metallogenic system.The histogram of fluid inclusion homogenization temperature that rangesbetween 130-260 ℃ is evidently bimodal, which shows an character of evolutionary stages from medium to lowtemperature hydrothermal deposit.The salinity of those fluid inclusions tends to concentrated in a smaller range of13.5% - 17.6% ,this shows that the hydrothermal ore-forming solution is medium-high salinity fluids.The gasphase compositions of fluid inclusions is primary 1-120 with a few of CO2, CH4 and H2.The complex anion groupand negative ions in liquid phase compositions is mainly F, CI and SO42, and the mainly positive ion containsNa＋,K＋,Ca2＋ and Mg2＋.It seems that there is a dynamometamorphic metallogenic stage after the hydrothermalmineralization period whose metallogenetic epoch is mainly Indo-China period to early Yanshan epoch.The golddeposit is the product of mixed hydrothermal mineralization which is concerned with sodic diorite magmatismduring Indo-China period to early Yanshan epoch in the lithosphere expansion dynamic background.After that, thedeposit has experienced the dynamic metamorphism of brittle-ductile shear in Himalayan period and finallydeveloped a polygenetic compound ore deposit.

关 键 词：矿床成因 流体包裹体 播卡金矿床 东川地区 云南省 

分 类 号：P618.51[天文地球—矿床学]