滇西大坪金矿床地质特征及成因初探
Geological characteristics and genetic type of Daping gold deposit in the Ailaoshan orogenic belt, SW China
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摘要: 大坪金矿床被视为哀牢山造山带南段最典型的造山型金矿,但其诸多地质特征明显不同于国外典型造山型金矿床,而呈现出与浅成低温热液型金矿床的一致性。区域上,脉型金铜铅银矿床的产出与中酸性侵入岩及中基性火山岩密切相关。大坪金矿床形成于主要赋矿的桃家寨闪长岩侵位之后约800Ma的新生代构造-岩浆热事件中,金矿床是区域尺度伸展和转换拉伸应力体制的产物;成矿作用过程中,研究区构造动力体制发生了转换,主成矿期容矿断裂带显示为张剪性正断层性质。矿脉多(55条)、薄(0.2~0.8m)、长(200~1500m)、陡(56°~85°)、延深大(约700m),且近平行成带产出;矿体中Au品位高(超过10×10-6),Au/Ag低(0.1~0.5),且伴生Pb、Cu、Ag。矿石的充填型结构构造和矿物共生组合指示矿脉形成温度低、深度浅;矿化-蚀变样式以及蛋白石和氧化矿的出现表明成矿体系处于开放的氧化环境,成矿后保存良好。大坪金矿床这种特殊的地质特征可能与其复杂的区域构造背景及成矿演化过程密切相关,金矿床虽然具有造山型金矿的基本特征,但在成矿作用晚期,矿床浅部叠加了浅成低温热液型金铜铅银成矿作用。即大坪金矿床属于深部造山型+浅部低温热液型矿床套叠组合,成矿体系保存完整,现发现的均为浅部矿体,深部找矿潜力巨大。Abstract: Daping gold deposit, situated in the south section of the Ailaoshan orogenic belt, once considered to be an orogenic gold deposit, displays many distinct geological characteristics which are inconsistent with the classical orogenic gold deposits around the world, but accord with the epithermal gold deposits. The vein type gold, copper, lead, silver deposits commonly develop in close association with intermediate-acidic intrusive and intermediate-basic volcanic rocks regionally. Daping gold deposit was formed in the Neozoic tectonic-magmatic activity, which is 800Ma later than the emplacement of Taojiazhai diorite which is the main host rocks, besides the gold metallogenesis is closely related to the regional structural framework and the transition of tectonic regime. The host faults of main ore-forming period are generally believed as a transtensional normal faults, and ore veins within are abundant (55), thin (0.2~0.8m), long (200~1500 m), steep (56°~85°), deeply extensive (700m) and developed in parallel, besides ore bodies in association with Pb, Cu and Ag display high-grade Au (above 10×10-6), low Au/Ag ratio (0.1~0.5). Textures and structures of filling type as well as mineral assemblages indicate that ore veins formed at a low-temperature and shallow-depth environment, what' more, mineralization-alteration types and the growth of opal and oxidized ores restrict an open and oxidizing environment. The distinguished geological characteristics of Daping gold deposit may be closely related to the complicated tectonic regime and metallogenic evolution, though the deposit is distinguished by its feature of orogenic gold deposits, epithermal gold, copper, lead, silver mineralization is overlapped in the shallow during the late stage of mineralization. The metallogenic characteristics, combined with documented geological information, indicate Daping gold deposit is distinguished by its orogenic in the deep and epithermal in the shallow, besides the metallogenic system is well preserved. Considering all the ores proven now are in the shallow, Daping gold deposit is of great prospecting potentiality in the deep.
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[1] 毕献武, 胡瑞忠, 何明友. 1996. 哀牢山金矿带的成矿时代及其成矿机制探讨. 地质地球化学, 24(1): 94-97
[2] 毕献武, 胡瑞忠, 何明友. 1997. 哀牢山金矿带主要金矿床成矿流体特征. 矿物学报, 17(4): 435-441
[3] 毕献武, 胡瑞忠. 1999. 云南大坪金矿床矿化剂来源及其对金成矿的制约. 矿物学报, 19(1): 28-33
[4] 邓军, 侯增谦, 莫宣学, 杨立强, 王庆飞, 王长明. 2010a. 三江特提斯复合造山与成矿作用. 矿床地质, 29(1):37-42
[5] 邓军, 杨立强, 葛良胜, 袁士松, 王庆飞, 张静, 龚庆杰, 王长明. 2010b. 滇西富碱斑岩型金成矿系统:基本特征及其变化与保存. 岩石学报, 26(6): 1633-1645
[6] 葛良胜, 邓军, 李汉光, 杨立强, 张文钊, 袁士松, 邢俊兵. 2007. 云南大坪大型金多金属矿床叠加成矿作用:地质、流体包裹体和稳定同位素证据. 岩石学报, 23(9): 2131-2143
[7] 韩润生, 金世昌. 1994. 云南元阳金矿床成因及找矿标志. 有色金属矿产与勘查, 3(4): 218-222
[8] 韩润生, 金世昌, 雷丽. 1997. 云南元阳大坪改造型金矿床的成矿热液系统地球化学. 矿物学报, 17(3): 337-344
[9] 胡瑞忠, 毕献武, 何明友, 刘秉光, Turner G, Burnard PG. 1998. 哀牢山金矿带矿化剂对金成矿的制约. 中国科学(D辑), 28(增): 24-30
[10] 胡瑞忠, 毕献武. 1999. 哀牢山成矿带成矿流体的He和Ar同位素地球化学. 中国科学(D辑), 29(4): 321-330
[11] 胡云中, 唐尚鹑, 王海平, 杨岳清, 邓坚. 1995. 哀牢山金矿地质. 北京:地质出版社, 1-278
[12] 李定谋, 曹志敏, 覃功炯, 何叔欣, 李保华, 温春齐, 徐则民. 1998. 哀牢山蛇绿混杂岩带金矿床. 北京:地质出版社, 1-137
[13] 李定谋, 李保华. 2000. 云南哀牢山金矿床的成矿条件. 沉积与特提斯地质, 20(1): 60-77
[14] 戚学祥, 王秀华, 朱路华, 胡兆初, 李志群. 2010. 滇西印支地块东北缘新元古代侵入岩形成时代的厘定及其构造意义:锆石LA-ICP-MS U-Pb定年及地球化学证据. 岩石学报, 26(7): 2141-2154
[15] 宋焕斌, 祁斌, 韩润生. 1990. 云南大坪金矿床控矿断裂受力机制分析. 矿产与地质, 4(4):21-26
[16] 孙晓明, 熊德信, 石贵勇, 王生伟, 翟伟. 2006a. 云南大坪金矿白钨矿惰性气体同位素组成特征及其成矿意义. 岩石学报, 22(3): 725-732
[17] 孙晓明, 熊德信, 王生伟, 石贵勇, 翟伟. 2006b. 壳幔相互作用及其对哀牢山金矿带金成矿的贡献: 以云南大坪金矿为例. 见:地质地球化学研究进展-庆贺王德滋院士致力于地质科学六十周年暨80华诞. 南京: 南京大学出版社, 269-279
[18] 孙晓明, 石贵勇, 熊德信, 王生伟, 翟伟, 屈文俊, 杜安道. 2007a. 云南哀牢山金矿带大坪金矿铂族元素(PGE)和Re-Os同位素地球化学及其矿床成因意义. 地质学报, 81(3): 394-404
[19] 孙晓明, 熊德信, 石贵勇, 王生伟, 翟伟. 2007b. 云南哀牢山金矿带大坪剪切带型金矿成矿40Ar/39Ar定年. 地质学报, 81(1): 88-92
[20] 熊德信, 孙晓明, 石贵勇, 王生伟, 高剑锋, 薛婷. 2006a. 云南大坪金矿白钨矿微量元素、稀土元素和Sr-Nd同位素组成特征及其意义. 岩石学报, 22(3): 733-741
[21] 熊德信, 孙晓明, 翟伟, 石贵勇, 王生伟. 2006b. 云南大坪金矿含金石英脉中高结晶度石墨包裹体: 下地壳麻粒岩相变质流体参与成矿的证据. 地质学报, 80(9): 1448-1456
[22] 熊德信, 孙晓明, 翟伟, 石贵勇, 王生伟. 2007a. 云南大坪韧性剪切带型金矿富CO2流体包裹体及其成矿意义. 地质学报, 81(4): 640-653
[23] 熊德信, 孙晓明, 石贵勇. 2007b. 云南哀牢山喜马拉雅期造山型金矿带矿床地球化学及成矿模式. 北京: 地质出版社, 1-144
[24] 徐研非. 1989. 元阳大坪石英脉型金矿床地质特征.云南地质, 8(2): 171-177
[25] 杨立强, 刘江涛, 张闯, 王庆飞, 葛良胜, 王中亮, 张静, 龚庆杰. 2010. 哀牢山造山型金成矿系统:复合造山构造演化与成矿作用初探. 岩石学报, 26(6):1723-1739
[26] 杨立强,邓军,赵凯,刘江涛. 2011. 哀牢山造山型金矿的成矿时序及其动力学背景探讨. 岩石学报, 27(9):2519-2532
[27] 应汉龙. 1998. 云南大坪金矿床围岩蚀变和同位素地球化学特征. 黄金科学技术, 6(4): 14-23
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