内蒙古哈达门沟金矿床地质特征及成矿作用探讨  

Study on Geological Characteristics and Metallogenesis of the Hadamengou Gold Deposit in Inner Mongolia

作　　者：侯万荣[1] 聂凤军[2] 张纯歌 徐斌[3] 李伟[4] 赵广明[1] 孟建军[1] 

机构地区：[1]武警黄金第二支队,呼和浩特010010 [2]中国地质科学院矿产资源研究所,北京100037 [3]武警黄金第一总队,哈尔滨150086 [4]中国黄金集团包头鑫达公司,内蒙古包头014060

出　　处：《地质学报》2014年第8期1549-1560,共12页Acta Geologica Sinica

基　　金：国家重点自然科学基金项目(编号41030421);危机矿山接替资源找矿项目(编号20089948);地质矿产调查项目(编号12120113072200)资助的成果

摘　　要：哈达门沟金矿床地处华北克拉通北缘阴山隆起带南缘乌拉山复背斜南翼，金矿体主要产于新太古界乌拉山群变质岩中，主要矿石类型包括含金石英脉、含金石英-钾长石脉、含金钾化蚀变岩等。成矿流体主要为中低温（160～300℃）、中低盐度（5％～15％ NaCleq），气相成分以 H2 O 和 CO2为主，液相组分阴离子以 Cl-和SO2-4为主，阳离子以Na＋、K＋和Ca2＋为主。矿石δ34 S变化于-21．7‰～5．4‰，极差为27．1‰，说明成矿物质来源的复杂性，平均值为-10．6‰，表现出亏损重硫的特点，硫继承了太古代地层中硫的同位素特点，并混有深部含矿流体的硫。矿石铅同位素组成、单阶段模式年龄、Th/U 比值、μ值变化范围较大，表现出多源特点，在铅构造模式图上，投点比较分散，表明哈达门沟矿石铅来源的复杂性。氢-氧同位素表明，成矿流体来源于岩浆水和部分变质热液，后期有天水的混入。矿石辉钼矿 Re-Os 同位素加权平均年龄为386．4±2．7Ma，等时线年龄为386．6±6．1 Ma ，金钼矿床主要成矿时代为早泥盆世，后期有多期热液活动叠加。矿床形成于弧-陆碰撞后的伸展构造背景。Hadamengou large gold deposit inInner Mongolia is one of the important deposit,located in southern margin of Wulashan anticlinorium of Yinshan uplift （west part of the Inner Mongolian earth axis ）on the north margin of North China Craton.The gold orebodies mainly lies in the metamorphic rock of Wulashan Group,Archaeozoic erathem.,main ore type include gold-bearing quartz vein type,gold-bearing quartz-potassic feldspar vein type, gold-bearing altered rock type. ore-forming fluid is characterized by intermediate-low temperature（160-300℃）,mid-low salinity（5%-15% NaCleq）.The gas component of fluid inclusions is dominated by H2 O and CO2 ,The main anions in the liquid composition are Cl- and SO2-4 ,and the cations are Na＋,K＋ and Ca2＋.The sulfur isotope composition of the oreδ 34 S vary from-21.7‰ to 5.4‰,the change range is 27.1‰,average value is -10.6‰,depleted 34S,indicated the sources of ore-forming material are complexity,sulfur isotope composition inherited archean strata,mixed with sulfur in deep-sourced ore-bearing Fluid.Lead isotopic compositions of the ore,single-stage model age,Th/U ratios,μ value vary in a large range, indicated multiple sources characteristics. In plumbotectonic model diagram by Zartman and Doe,the lead isotopic compositions of ore mineral plotted scattered,this demonstrates that the ore lead came from the mixed lead.Hydrogen and oxygen isotopes show that the ore-forming fluid was derived from magmatic and small metamorphic water,Late mixed with meteoric water.molybdenite Re-Os weighted mean age is386.4±2.7Ma and isochron age is 386.6±6.1Ma of the orestone,which show the main metallogenic epoch is early devonian,later multi-phase hydrothermal activity probably superimposed on the early stages.The deposit formed in intracontinental extensional tectonic setting after arc-continental collision.

关 键 词：华北克拉通北缘 金矿床 地质特征 成矿作用 内蒙古哈达门沟 

分 类 号：P618.51[天文地球—矿床学]