Magmatism and provenances of mineralization zones in Sumatra (Indonesia)and their comparisons to adjacent terrains
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摘要: 本文介绍了苏门答腊岛上两个成矿带(即铜-金矿成矿带和锡矿成矿带)的矿产分布,岩浆岩的岩石类型和地球化学特征。根据本研究课题在巴东地区岩石化学资料,本文总结了铜-金矿成矿带含矿母岩的地球化学特征,探讨其岩浆岩成因和源区。同时,将其锡矿成矿带岩浆岩的岩石类型和地球化学-大地构造环境与其相邻地体进行对比。研究结果表明:西苏门答腊地体的铜-金矿成矿带的含矿母岩为SI-型埃达克质花岗岩,形成于活动大陆边缘(ACM)火山弧构造环境,其岩浆物质主要来源于俯冲洋壳板片局部熔融叠加上弱的地幔楔熔融-混染作用(MASH)。而东苏门答腊地体‘锡岛’和“暹缅马苏”地体的锡矿带含矿母岩为过铝质(S-型)花岗岩类,其形成构造环境为碰撞带的弧后盆地和陆内裂谷,物质源区来自地壳重熔和岩浆分异。地球化学资料表明,该两地体具有共同的深部岩浆源区。Abstract: This paper introduces the mineral distribution, igneous rock types and their geochemical characteris-tics within two mineralization zones (i.e. Cu-Au- and Sn-mineralization zones). Based on the litho-chemical data taken from our research project, the authors summary the geochemical characteristics of ore-bearing igneous par-ent rock and discuses the magmatic origin and source area in Cu-Au-mineralization zone. Meanwhile, a compari-son of rock types of magma and geochemistry-tectonic setting for Sn-mineralization zones in Sumatra Island to the adjacent Terrains is made here. The results of this study indicate that the ore-bearing parent rocks of Cu-Au mineralization zones in the West Sumatra Terrain are adakitic granitoids (SI-Type) were formed in the tectonic setting of volcano-arc in active continental margin(ACM)and the igneous matter came from partly melting of sub-ducted ocean-slab plus weakly melting-assimilation within mantle wedge(MASH),Whereas the ore-bearing ig-neous parent rock in tin mineralization zones within the‘tin island’of East Sumatra Terrain as well as“Sibumasu Terrain”are peraluminum granitoids(S-Type) belonging to tectonic setting of backed arc basin or rift within con-tinent after collision zone and were derived from the re-melting of crust and igneous fraction crystal. The geo-chemical data show that the East Sumatra Terrain and the West Sumatra Terrain may have the same deep igneous source area.
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