| 内蒙古拜仁达坝-维拉斯托银多金属矿床的矿相学特征 |
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| 引用本文：刘妍,江思宏,张志刚,刘翼飞,聂凤军.2011.Mineragraphy of Bairendaba and Weilasituo silver-polymetallic deposits in Inner Mongolia[J].Mineral Deposits,30(5):837~854 |
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| 基金项目:本文得到国家重点自然科学基金项目(编号：41030421)、中央级公益性科研院所基本科研业务费专项资金（编号：K0704）、全国危机矿山项目（编号：20089948）和地质大调查项目（编号：1212010911029）联合资助 |
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| 中文摘要:拜仁达坝和维拉斯托是近年来在内蒙古东部地区发现的2个大型银多金属矿床。文章通过岩相学、BSE图像与电镜能谱等手段对其矿相学特征进行了系统研究。笔者结合矿床地质特征，厘清了2个矿区金属矿物的种类、产出状态及生成顺序，共确定3期4个阶段的矿化作用。第1期成矿作用主要形成胶状黄铁矿，代表低温热（水）的沉积环境。第2期成矿作用是一次中高温热液成矿作用，以高温矿物毒砂与锡石为标志，形成As-S金属硫化物矿化：黄铁矿+闪锌矿+方铅矿+磁黄铁矿+黄铜矿+毒砂+锡石，随后经历了强烈的构造破碎和强烈的糜棱岩化，形成了一系列具有脆性变形-角砾状和塑性变形-糜棱状结构构造特征的矿石类型。第3期成矿作用包括2个成矿阶段：第1阶段为中高温热液成矿阶段，形成一系列富S的金属矿化和Bi+Ag的金属硫化物：毒砂→黄铁矿→自然Bi+硫银铋矿→方铅矿+磁黄铁矿+闪锌矿+黄铜矿等；第2阶段为中-低温热液活动，形成一系列贫S富Sb+Ag的金属硫化物：磁黄铁矿+方铅矿+闪锌矿→纤硫锑铅矿+银黝铜矿→六方锑银矿+锑银矿→自然银。其中铅锌矿化与第2、3期成矿作用有关，而银矿化主要与第3期成矿作用的第4阶段有关。 |
| 中文关键词:地质学 矿相学 银多金属矿床 拜仁达坝 维拉斯托 内蒙古 |
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| Mineragraphy of Bairendaba and Weilasituo silver-polymetallic deposits in Inner Mongolia |
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| Abstract:Bairendaba and Weilasituo are two silver-polymetallic deposits discovered in recent years in eastern Inner Mongolia. Mineragraphic studies by using the SEMEDX revealed the modes of occurrence of the silver-bearing minerals such as allargentium, dyscrasite, argentobismutite, freibergite and native silver. Metallic minerals in these two deposits are summarized systematically, including their modes of occurrence and formation sequences. The commonly existent jelly-like pyrite is regarded as the product of the earliest ore-forming stage, suggesting a hot water sedimentary environment at low temperature. During the later meso-hypothermal ore-forming process, the assemblage of pyrite + sphalerite + galena + pyrrhotite + chalcopyrite + arsenopyrite + cassiterite was formed. Subsequently, these minerals were crushed and mylonitized intensely, and the ores were characte-rized by plastic deformation-brecciated and mylonitic structure. After this structural deformation, another meso-hypothermal ore-forming process took place, forming the S-rich metallic mineralization and Bi+Ag sulfides of pyrite → native bismuth + argentobismutite → galena + pyrrhotite + sphalerite + chalcopyrite. During the subsequent meso-epithermal ore-forming process, a series of S-poor, Sb- and Ag-rich sulfides were formed, such as pyrrhotite + galena + sphalerite → robinsonite + freibergite → allargentium + dyscrasite → native silver. In general, three periods (composed of 4 stages) of mineralization occurred in the ore deposits, whereas Pb and Zn mineralizations were related to the second and third periods, and the silver mineralization was probably related to the late stage of the third period. |
| keywords:geology, mineragraphy, silver polymetallic deposit, Bairendaba, Weilasituo, Inner Mongolia |
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