老挝爬奔金矿床地质特征及成因探讨
发布时间：2018-07-23 21:17
【摘要】：老挝爬奔金矿床产出于昌都—思茅—南邦陆块二叠系沉积岩地层中,是一个以灰岩为容矿围岩的中低温热液金矿床。矿体主要赋存于二叠纪灰岩中,严格受地层和构造破碎带及片理化带控制,呈层状、似层状和囊状产出。本文在对爬奔地区金矿床地质特征和主要控矿因素研究基础之上,分析该矿流体包裹体、碳氧同位素以及微量元素分布特征与矿化关系,取得主要成果和认识为：1、确认了本区主要的含矿建造为二叠纪灰岩(内源碎屑沉积岩),为成矿提供了物质基础,成矿流体在灰岩地层内的断裂和裂隙中发生循环对流使金的活化,迁移,沉淀,富集成矿。2、研究区内北东向断裂带为其成矿与控矿的主要因素,并经过后期多次的叠加改造形成爬奔金矿。断裂带不仅是本区的导矿构造,也为成矿提供其就位的空间。3、区域化探结果显示As、Hg、Sb、Ti等元素组合异常,矿物组合上出现雄黄、雌黄、毒砂、辰砂、绢云母等一系列典型的低温热液矿物组合,说明热液温度较低。还可见少量闪锌矿、方铅矿、黄铜矿、黄铁矿等,以此确定为矿热液为中—低温岩浆期后流体,这也与包裹体测温结果一致(120°～340°)。4、根据爬奔金矿地质地球化学分析结果可以认为,矿床成矿流体总体具中低温、多期段的特点。金矿成矿存在2期：第一期温度较高,大于300℃；第二期160～240℃流体包裹体较高温阶段盐度变化范围为(1.22～2.55)wt%,平均值为1.77wt%,较低温阶段盐度变化范围为(4.17～16.7)wt%,平均值为7.64wt%,总体盐度较低,说明其成矿流体主要为岩浆期后热液,同时伴随着大气水热液的存在,可能为混合热液。矿石方解石碳氧同位素13Cv-PDB(‰)值分布在-4.5--5.2之间,18Ov-SMOW(‰)值分布于20.0-20.8之间,矿区样品同位素组成特征相对集中,表明其成因单一,为同成因。综上所述,爬奔金矿成因可认为是受断裂控制,成矿物质来源于围岩,断裂活动为成矿主要动力机制。因此,爬奔金矿是受断裂控制的岩浆热液体系加古大气降水混合作用而形成的中低温热液交代—充填矿床。
[Abstract]:The Changdu-Simao-Nanbang gold deposit, which occurs in the Permian sedimentary strata of Changdu-Simao-Nanbang block, is a medium-low temperature hydrothermal gold deposit with limestone as its host rock. The orebodies mainly occur in Permian limestone and are strictly controlled by stratigraphic and structural fracture zones and sheet physical and chemical zones. They are stratiform, stratiform and cystic. On the basis of the study of geological characteristics and main ore-controlling factors of the gold deposit, the relationship between mineralization and fluid inclusions, carbon and oxygen isotopes, and the distribution of trace elements in the deposit is analyzed in this paper. The main achievements and understanding are: 1. It is confirmed that the main ore-bearing formations in this area are Permian limestone (endogenous clastic sedimentary rocks), which provides a material basis for mineralization. The circulation convection of ore-forming fluid in the faults and fissures of limestone strata causes gold to be activated, migrated, precipitated and enriched. The north-east fault zone in the study area is the main factor of metallogenic and ore-controlling. And after a number of late superposition transformation of the formation of the climbing gold deposit. The fault zone is not only the ore-conducting structure in this area, but also provides the space for metallogeny. The results of regional geochemical exploration show that the element assemblages, such as the assemblage of Asae Hgfen, Sbnti, and so on, are abnormal, and the mineral assemblages appear realgar, arsenopyrite, cinnabar, etc. A series of typical low temperature hydrothermal mineral assemblages, such as sericite, indicate that the hydrothermal temperature is relatively low. A small amount of sphalerite, galena, chalcopyrite, pyrite and so on can also be found. It is also consistent with the results of inclusion temperature measurement (120 掳~ 340 掳) .4.According to the geological and geochemical analysis of the Cepong gold deposit, it can be concluded that the ore-forming fluid of the deposit is generally of the characteristics of middle and low temperature and multi-stage. There are two stages of gold mineralization: the first stage is higher than 300 鈩，
本文编号：2140680
[Abstract]:The Changdu-Simao-Nanbang gold deposit, which occurs in the Permian sedimentary strata of Changdu-Simao-Nanbang block, is a medium-low temperature hydrothermal gold deposit with limestone as its host rock. The orebodies mainly occur in Permian limestone and are strictly controlled by stratigraphic and structural fracture zones and sheet physical and chemical zones. They are stratiform, stratiform and cystic. On the basis of the study of geological characteristics and main ore-controlling factors of the gold deposit, the relationship between mineralization and fluid inclusions, carbon and oxygen isotopes, and the distribution of trace elements in the deposit is analyzed in this paper. The main achievements and understanding are: 1. It is confirmed that the main ore-bearing formations in this area are Permian limestone (endogenous clastic sedimentary rocks), which provides a material basis for mineralization. The circulation convection of ore-forming fluid in the faults and fissures of limestone strata causes gold to be activated, migrated, precipitated and enriched. The north-east fault zone in the study area is the main factor of metallogenic and ore-controlling. And after a number of late superposition transformation of the formation of the climbing gold deposit. The fault zone is not only the ore-conducting structure in this area, but also provides the space for metallogeny. The results of regional geochemical exploration show that the element assemblages, such as the assemblage of Asae Hgfen, Sbnti, and so on, are abnormal, and the mineral assemblages appear realgar, arsenopyrite, cinnabar, etc. A series of typical low temperature hydrothermal mineral assemblages, such as sericite, indicate that the hydrothermal temperature is relatively low. A small amount of sphalerite, galena, chalcopyrite, pyrite and so on can also be found. It is also consistent with the results of inclusion temperature measurement (120 掳~ 340 掳) .4.According to the geological and geochemical analysis of the Cepong gold deposit, it can be concluded that the ore-forming fluid of the deposit is generally of the characteristics of middle and low temperature and multi-stage. There are two stages of gold mineralization: the first stage is higher than 300 鈩，
本文编号：2140680
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