内蒙古黄岗锡铁矿床夕卡岩矿物学特征及其成矿指示意义  

Mineralogical characteristics of skarns in the Huanggang Sn-Fe deposit of Inner Mongolia and their metallogenic indicating significance

作　　者：周振华[1] 刘宏伟 常帼雄 吕林素[4] 李涛 杨永军 张瑞军 纪显合 

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037 [2]内蒙古矿产实验研究所,内蒙古呼和浩特010031 [3]内蒙古地质勘查有限责任公司,内蒙古呼和浩特010020 [4]中国地质博物馆,北京100034 [5]内蒙古黄岗矿业有限责任公司,内蒙古克什克腾旗016100

出　　处：《岩石矿物学杂志》2011年第1期97-112,共16页Acta Petrologica et Mineralogica

基　　金：中国地质调查局地质调查项目(1212010010923);内蒙古重要矿产资源潜力评价及区域成矿规律研究项目(2006-02-YS01);中央级公益性科研院所基本科研业务费项目(K0921);中国地质大学(北京)2008年度优秀博士论文扶持奖励基金项目

摘　　要：为进一步查明黄岗锡铁矿矿床成因、夕卡岩矿物成分与金属矿化类型之间的联系,利用电子探针对研究区主要夕卡岩矿物的化学成分进行了详细的分析。测试结果表明,成矿早期石榴石的端员组分以钙铁榴石为主,主成矿期石榴石的端员组分以钙铝榴石为主;辉石端员组分变化较大,主要为透辉石和钙铁辉石。石榴石和辉石的矿物组分分别为Adr28.69～96.44Grs2.00～67.38(Prp+Sps)0.67～5.69和Di11.8～94.12Hd4.08～81.28Jo1.79～20.02,其较大的成分变化特征反映出夕卡岩不是在一个完全封闭的平衡条件下形成的。角闪石大多为镁铁钙角闪石,个别属于铁角闪石,成分变化较大的原因可能是由于氧化还原条件改变导致不同程度的AlⅥSi←→(Na,K)的置换作用,属于一种固相线下的转变。角闪石中四次配位的Si、Al及六次配位的Al、Ti和A位置的阳离子数变化范围很大,可能是由于接触交代作用过程中岩浆的成分差异或结晶时的物理化学条件改变所引起的。富锰的辉石夕卡岩是岩浆流体顺层间破碎带渗滤交代形成的,富锰辉石可作为本区寻找Sn、Cu、Zn等多金属的找矿标志,外接触带夕卡岩和其附近的大理岩中是多金属成矿的有利部位。The Huanggang Sn-Fe deposit is a large-size skarn deposit hosted by Lower Permian marble of Huanggangliang Formation. Its skarn mineral assemblage mainly consists of diopside, andradite-grossular and vesuvianite, and its retrograde minerals include actinolite-tremolite, epidote, chlorite, serieite, grossular etc. Electron microprobe analyses show that the end member of garnet in the early stage is dominated by andradite, while that in the major ore-forming stage is dominated by grossular, and that the end member of pyroxene has changedgreatly, composed mainly of diopside and hedenbergite. Components of garnet and pyroxene are Adr28.69～9644Grs2.00～67.38（Prp＋Sps）0.67～5.69 and Di11.8～94.12Hd4.08～81.28Jo1.79～20.02, respectively, their wide compositional variation range suggests that skarns were not formed under the totally enclosed equilibrium condition. The amphiboles mostly belong to magnesium-ferric-calcium amphibole, with only some individuals being ferric-hornblende. The relatively remarkable change of composition is probably attributed to the change of redox conditions resulting in different degrees of AlM Si→←（Na, K） displacement, which belongs to the transforming tendency under solidus. Tetrahedral Si, Al, octahedral Al, Ti and cations in A site of amphibole change greatly, which may be caused by the composition difference of the magma in the contact metasomatic process or the change of physicochemical condition during crystallization. Electron microprobe analysis shows that the early skarns in Huanggang belong to the typical oxidation type, while the late skams transfer to the reduction type. From the viewpoint of mineral assemblages, the skarn assemblage Composition characteristics of skarns in the Huanggang calcareous-magnesian skarn formation, while the altered in this area is similar to the calcareous skarn formation. Sn-Fe deposit are similar to those of Cu-Fe deposits of mineral assemblage is close to W-Sn deposits of the cal- careous skarn formation, indicating a new skarn fo

关 键 词：夕卡岩 矿物学 成岩成矿 黄岗锡铁矿 内蒙古 

分 类 号：P57[天文地球—矿物学] P618.4[天文地球—地质学]