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| 满洲里地区银铅锌矿床成矿流体特征及矿床成因 | |
| 引用本文： | 武广,糜梅,高峰军,李宗彦,乔翠杰.满洲里地区银铅锌矿床成矿流体特征及矿床成因[J].地学前缘,2010,17(2):239. |
| 作者姓名： | 武广 糜梅 高峰军 李宗彦 乔翠杰 |
| 作者单位： | 1. 中国科学院,广州地球化学研究所,成矿动力学重点实验室,广东,广州,510640;中国地质科学院,矿产资源研究所,北京,100037;河南省灵宝市金源矿业有限责任公司,河南,灵宝,472500 2. 中国科学院,广州地球化学研究所,成矿动力学重点实验室,广东,广州,510640 3. 河南省灵宝市地质矿产局,河南,灵宝,472500 4. 河南省灵宝市金源矿业有限责任公司,河南,灵宝,472500 |
| 基金项目： | 国家自然科学基金，国家科技支撑计划 |
| 摘 要： | 满洲里地区是得尔布干成矿带最重要的银铅锌矿床产出地区。文中以额仁陶勒盖银矿床和查干布拉根银铅锌矿床为例,系统研究了该区银铅锌矿床成矿流体特征,探讨了矿床成因类型。研究表明,额仁陶勒盖银矿床以气液两相水溶液包裹体为主,流体包裹体均一温度为242～334℃,平均265℃,盐度(质量分数)为1.73%～4.48%NaCl_(eqv),平均2.70%NaCl_(eqv),流体密度为0.72～0.84 g/cm~3,平均0.80 g/cm~3,流体压力为13～26 MPa,平均18 MPa,对应的成矿深度为0.5～1.0 km,平均0.7 km,成矿流体总体上属于H_2O-NaCl体系。查干布拉根银铅锌矿床发育气液两相水溶液包裹体、含CO_2包裹体和纯CO_2包裹体,流体包裹体均一温度为179～367℃,平均261℃,盐度(质量分数)为2.23%～6.87%NaCl_(eqv),平均4.35%NaCl_(eqv),流体密度为0.65～0.91 g/cm~3,平均0.82 g/cm~3,成矿压力为15～46 MPa,平均25 MPa,对应的成矿深度为0.6～1.7km,平均0.9 km,成矿流体总体上属于H_2O-CO_2-CH_4-NaCl体系。两个矿床的成矿流体均属于中低温、低盐度、中等密度流体。额仁陶勒盖银矿床成矿流体主要来自大气降水,大气水的混入是银沉淀的主要机制,其矿床成因属于浅成低温热液型;查干布拉根银铅锌矿床成矿流体属于岩浆水与大气降水的混合水,流体不混溶作用或沸腾作用是查干布拉根矿床银铅锌沉积的主要机制,其矿床成因属于中低温热液脉型。满洲里地区银铅锌矿床的成矿时代为早白垩世,成矿与晚侏罗世—早白垩世火山-侵入岩浆活动晚期的火山-次火山热液密切相关,矿床产出于伸展背景下的中生代陆相火山断陷盆地中。 |
| 关 键 词： | 流体包裹体 额仁陶勒盖银矿床 查干布拉根银铅锌矿床 矿床成因 满洲里地区 内蒙古 |
Ore-forming fluid characteristics and genesis of silver-lead-zinc deposits in the Manzhouli area, Inner Mongolia, China |
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| Wu Guang,Mei Mei,Gao Fengjun,Li Zongyan,Qiao Cuijie.Ore-forming fluid characteristics and genesis of silver-lead-zinc deposits in the Manzhouli area, Inner Mongolia, China[J].Earth Science Frontiers,2010,17(2):239. | |
| Authors: | Wu Guang Mei Mei Gao Fengjun Li Zongyan Qiao Cuijie |
| Abstract: | The Manzhouli area located in the northeastern part of Inner Mongolia is the most important Ag-Pb-Zn metallogenic province in the Derbugan metallogenic belt. In this paper, the authors systematically studied the fluid inclusions of the Ag-Pb-Zn deposits and discussed their ore genetic types with the Erentaolegai and Chaganbulagen deposits as examples. In the Erentaolegai Ag deposit, the fluid inclusions are characterized by aqueous two-phase inclusion, with homogeneous temperatures of 242 to 334 ℃ (averaging 265 ℃), salinities of 1.73 wt% to 4.48 wt% NaCl_(eqv) (averaging 2.70 wt% NaCl_(eqv)) and densities of 0.72 to 0.84 g/cm~3 (averaging 0.80 g/cm~3). In the Chaganbulagen Ag-Pb-Zn deposit, fluid inclusions can be classified into types of aqueous two-phase, CO_2-bearing and pure CO_2;their homogenization temperatures, salinities and densities range from 179 to 367 ℃ (averaging 261 ℃), 2.23 wt% to 6.87 wt% NaCl_(eqv) (averaging 4.35 wt% NaCl_(eqv)) and 0.65 to 0.91 g/cm~3 (averaging 0.82 g/cm~3), respectively. The ore-forming pressures of the Erentaolegai and Chaganbulagen deposits varied from 13 to 26 Mpa with an average of 18 Mpa and from 15 to 46 Mpa with an average of 25 Mpa, respectively, corresponding to ore-forming depths of 0.5 to 1.0 km with an average of 0.7 km and 0.6 to 1.7 km with an average of 0.9 km, respectively. The ore-forming fluids of the both deposits were characterized by low-to-moderate temperature, low salinity and moderate density. The ore-forming fluids of the Erentaolegai and Chaganbulagen deposits generally belonged to H_2O-NaCl and H_2O-CO_2-CH_4-NaCl fluid systems, respectively. The ore-forming fluid of the Erentaolegai Ag deposit was mainly composed of meteoric water, and its genetic type belonged to epithermal. The ore-forming fluid of the Chaganbulagen Ag-Pb-Zn deposit consisted mainly of mixed water between magmatic water and meteoric water. And its origin belonged to epithermal-to-mesothermal lode deposit, and immiscibility or boiling action of ore-forming fluid was the dominant factor for silver, lead and zinc deposition. The Ag-Pb-Zn deposits were closely related to the volcanic and/or subvolcanic hydrothermal solutions of the late stage of the Late Jurassic-Early Cretaceous volcanic-magmatic activity. The mineralization period of the Ag-Pb-Zn deposits in the Manzhouli area was in the Early Cretaceous, those deposits occurred in the Mesozoic intra-continental volcano-fault basin with an extensional tectonic setting. |
| Keywords: | fluid inclusion Erentaolegai silver deposit Chaganbulagen silver-lead-zinc deposit ore genesis Manzhouli area Inner Mongolia |
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