摘要
白乃庙金矿位于中亚造山带南缘白乃庙岛弧区域,是华北地台北缘中段金成矿远景区的重要组成部分。本文通过白乃庙金矿床流体包裹体和C-H-O-S稳定同位素的系统工作,揭示其成矿物质来源、成矿流体性质以及矿床成因。流体包裹体测试均一温度(126.5~283.4℃)和盐度(0.88%~7.59%NaCl equiv)显示成矿流体具有中低温、低盐度的特征。C-H-O同位素特征(δD_(SMOW)为-129‰~-119.5‰,δ^(18)O H_(2)O为-11.06‰~-7.96‰;δ^(13)C_(PDB)为-5.80‰~-3.20‰,δ^(18)O_(SMOW)为-1.06‰~19.91‰)指示成矿热液主要来源于深部岩浆水和大气降水,且以大气降水为主体。δ^(13)C_(PDB)变化范围很小,而δ^(18)O_(SMOW)变化范围较大,这一特征表明成矿流体与围岩有明显的交换反应。S同位素数据(-1.82‰~-4.24‰)指示成矿物质主要来源于深部岩浆体系。综合矿床地质特征、成矿流体特征以及稳定同位素特征,认为白乃庙金矿为浅成低温热液型金矿床。
The Bainaimiao gold deposit is located in the Bainaimiao island arc in the southern margin of the Central Asian Orogenic Belt,and is an important part of the gold metallogenic prospective area in the middle section of the northern margin of the North China region.This work measured fluid inclusions and C-H-O-S stable isotopes of the Bainaimiao gold deposit in an attempt to reveal the ore-forming material source,the properties of ore-forming fluids and the deposit genesis.The homogeneous temperature(126.5~283.4℃)and salinity(0.88%~7.59%NaCl equiv)of fluid inclusions indicate that the ore-forming fluids are featured by medium-low temperature and low salinity.The isotopic characteristics of C-H-O(-129‰~-119.5‰forδD_(SMOW),-11.06‰~-7.96‰forδ^(18)O H _(2)O;-5.80‰~-3.20‰forδ^(13)C_(PDB),-1.06‰~19.91‰forδ^(18)O_(SMOW))reveal the ore-forming hydrothermal fluids were derived from deep magma water and atmospheric precipitation,with the latter as dominated.The small variation range of δ^(13)C_(PDB) and large variation range ofδ^(18)O_(SMOW)suggest that the ore-forming fluids have undergone exchange reaction with the surrounding rock.The S isotope data(-1.82‰~-4.24‰)indicate that the metallogenic materials were mainly originated from the deep magmatic system.Based on the geological characteristics of the deposit,and the characteristics of ore-forming fluids and stable isotopes,the Bainaimiao gold deposit is considered to be an epithermal gold deposit.
作者
袁硕浦
王建平
许展
王继春
吕钊
杨壮
YUAN Shuopu;WANG Jianping;XU Zhan;WANG Jichun;L Zhao;YANG Zhuang(School of Earth Science and Resources,China University of Geosciences(Beijing),Beijing 100083;Inner Mongolia Autonomous Region Geological Survey Institute,Hohhot,Inner Mongolia 010020)
出处
《地质与勘探》
CAS
CSCD
北大核心
2022年第2期286-298,共13页
Geology and Exploration
基金
内蒙古自治区地质勘查基金"内蒙古自治区中部满都拉-白乃庙一带铜金多金属矿成矿规律与找矿预测"(编号:2018-01-YS01)资助。
