新疆西昆仑奥尔托喀讷什锰矿地质、地球化学及成因  

Geology,geochemistry and ore genesis of the Aoertuokanashi manganese deposit,western Kunlun,Xinjiang,Northwest China

作　　者：高永宝[1] 滕家欣 李文渊[1] 陈登辉[1] 隋清霖[1] 荆德龙[1] 贺永康[1] 白建科[1] GAO YongBao;TENG JiaXin;LI WenYuan;CHEN DengHui;SUI QingLin;JING DeLong;HE YongKang;BAI JianKe(MLR Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits,Xi＇an Center of China Geological Survey,Xi＇an 710054,China)

机构地区：[1]国土资源部岩浆作用成矿与找矿重点实验室,中国地质调查局西安地质调查中心,西安710054

出　　处：《岩石学报》2018年第8期2341-2358,共18页Acta Petrologica Sinica

基　　金：陕西省青年科技新星项目(2015KJXX71); 陕西省自然科学基础研究计划面上项目(2018JM4030); 国家自然科学青年基金项目(41603050); 中国地质调查局地质调查项目(1212011121088、12120115019501、DD20160004、DD20160346);中国地质调查局青年地质英才计划(2013)联合资助 笔者在野外工作期间.得到新疆佰源丰矿业有限公司、中国冶金地质总局西北地质勘查院、中国冶金地质总局中南地质勘查院、新疆地矿局第二地质大队野外～线工作人员的大力协助;中国

摘　　要：近年来,西昆仑玛尔坎苏地区富锰矿找矿取得重大突破,新发现奥尔托喀纳什等大型锰矿床。该矿床层位稳定,厚度较大,Mn平均品位达35%以上,为中国最富的碳酸锰矿床,属于典型的海相沉积型锰矿床。锰矿体主要赋存于晚石炭世喀拉阿特河组地层中,该组岩性为一套浅海碳酸盐岩台地相沉积建造组合,可划分为台内浅滩、潮坪、开阔台地、局限台地等4个相类型。成矿分为三个期次,第一期为沉积成岩成矿期,矿石矿物由菱锰矿、锰方解石、硼锰矿组成;第二期为热液改造期,形成锰镁绿泥石、红锰矿、硫锰矿、锰方解石(脉)、重结晶菱锰矿、蔷薇辉石及滑石、石膏等;第三期为表生氧化期,发育少量软锰矿、水锰矿、硬锰矿等。锰矿石具有较低的Fe/Mn比值、V/(V+Ni)比值和强烈的Ce正异常,表明Mn是在氧化环境下,以氧化物或氢氧化物的形式沉积富集。含锰岩系顶、底板岩石中含较多成熟度较差的中酸性火山岩岩屑,以及具有较低Al/(Al+Fe+Mn)、Y/Ho、Co/Ni比值的锰矿石,说明其成矿物质来源于海底热水活动。奥尔托喀纳什锰矿具有"内源外生"的特点,锰矿石及菱锰矿具有负的δ^(13)C值(-23.3‰～-13.2‰),表明锰矿经历了先成锰氧化物或氢氧化物、再被还原转化成菱锰矿的过程。此外,有机质所导致的更为强烈的还原作用是本矿床富锰矿形成的重要机制。后期构造叠加致使矿体发生变形,矿体形态受褶皱控制。矿石受到强烈改造,形成锰镁绿泥石、红锰矿、蔷薇辉石等,晚期经历氧化淋滤作用形成软锰矿、水锰矿等。Recently,a new large manganese deposit,the Aoertuokanashi mine,was discovered in the Maerkansu area,western Kunlun,which is the richest manganese carbonate deposit so far found in China. The manganese ore belt in Maerkansu area is stable with a large thickness and a rich grade of more than 35% Mn contents. This deposit belongs to a typical marine sedimentary manganese deposit. The manganese ores occur in the Upper Carboniferous Kalaatehe Formation. This formation was formed in shallow sea carbonate platform environments,composed of four types of sedimentary facies,including platform shoal,tidal plat,open platform and restricted platform. Mineralization can be divided into three stages：（1） the first one is the sedimentary diagenetic stage,whose oreforming minerals are composed of rhodochrosite, manganese calcite and sussexite;（ 2） the second one is the hydrothermal transformation stage,whose ore-forming minerals are composed of manganchlorite,friedelite,manganese calcite vein,recrystallized rhodochrosite,rhodonite,talc and gypsum,etc.; and（ 3） the last one is the supergenetic oxidation stage,with few pyrolusite,manganite and psilomelane as its ore-forming minerals. The lower ratio values of Fe/Mn,V/（ V ＋ Ni）,and intense positive Ce anomalies show that the manganese were deposited as manganese oxides or hydroxides in oxidizing environments. Middle-acid volcanic fragments with poorer maturity were found in the roof and floor manganese-bearing rocks,with lower ratio values of Al/（ Al ＋ Fe ＋Mn）,Y/Ho and Co/Ni of manganese ores,indicating that the ore-forming materials come from the underneath hot water activities. The values of δ^（13）C in the manganese ores and rhodochrosites vary from-23. 3‰ to-13. 2‰,showing that there is a forming process from early manganese oxide or hydroxide to rhodochrosite by reduction. The strong reduction caused by organic matters is the key to the forming of rich manganese ores in the Aoertuokanashi manganese deposit. The ore bodies were deformed with la

关 键 词：地质特征 地球化学 C-O同位素 矿床成因 奥尔托喀讷什锰矿 西昆仑 

分 类 号：P595[天文地球—地球化学] P618.32[天文地球—地质学]