| The geotectonic location of Lanjia area lie in Xing' an-Mongolia lithospheric plate and late Paleozoic continental margin of Sino-Korea plate in early Mesozoic. And it entered into Circum-Pacific active continental margin, belonged to middle segment of Daheishan faulted uplift in Changbaishan uplift of Eurasia plate eastern active belt. As part of Songliao rift system, its North West segment is Songliao rift and South East is Yitong-Shulan rift.Because of the plate movement, Late Triassic Lanjia area developed deep-seated fractures and formed series of alkaline –normal NE-oriented intrusive belt. And the late Paleozoic formation were assimilated or swallowed. Therefore, residual formations were folded and metamorphosed.Hornfels, skarnization, troilite and gold mineralization were formed in their contact segment.Gold mineralization of Lanjia area can be divided into four types, such as skarn type, fractured alteration type, cryptoexplosive breccia type and quartz vein type.Skarn type is the predominant one. Complex ore bodies occur as shape of vein, vesicle and irregular mass. Its embranchment and recombination are very common. They are formed in contact belt of Indochinese quartz diorite and early Permian Fanjiatun group submarine sedimentation rocks. All ore bodies are controlled in outer belt of skarn belt composed by broken garnet skarn, garnet magnetite skarn and actinolite skarn. Ore textures consist of major xenomorphic crystal grain, minor idiomorphic, hipidiomorphic grain. Ore structures consist of major veinlet, microscopic vein, microscopic stockwork, radiating, sheaflike and disseminated structures, minor mass and spotted structures. Predominant minerals are composed by magnetite, pyrite, pyrrhotite, hematite, galenite, sphalerite, arsenopyrite, cobaltine, chalcopyrite, bismuthinite, native bismuth, tetrahedrite, scheelite and native gold. Gold occurs predominantly in the fractures of magnetite, bismuthinite, pyrite, garnet and actinolite as independent mineral. The qualities of gold reach to 816.40~989.70, average 977.00. Major associated elements are Bi and Ag. Wallrock are composed of skarnization, epidotization, albitization, haematization, hydromicazation and chloritization, minor silicatization, tourmalinization and fluoritization. Altered rock type gold mineralizations are hosted in second layer of first segment in fractured alteration zone of Fanjiatun group. The main alterations are pyritization and sericitization. Majority of minerals are pyrrhotite, pyrite, chalcopyrite, galenite, sphalerite, arsenopyrite and native gold. Metallic sulfides are the 5-10% of the total minerals.Cryptoexplosive breccia type gold mineralization are developed the contact belt of cryptoexplosive breccias and country rocks. Nowadays, research degree is very lower and single engineering control the gold mineralization.Quartz vein type gold mineralizations are hosted NEE contact belt of Cretaceous rhyolite porphyry and Yanshanian granite porphyry. The third ore veins are developed into the NW-trending structures of contact belt of quartz diorite and Fanjiadun group hornfels. Au, Bi, Sb are most dominant elements in this ore field and belong to strong enriched elements because their concentration Clarke are larger than 100. As, Ag, Cu, Mo belong to medium enriched elements because their concentration Clarke are 100~10. Pn, Zn belong to weak enriched elements because their concentration Clarke are 10~1. And the concentration Clarke of Hg is lower than Clarke value. Skarn type and alteration type of gold mineralization have different indicator element correlatability and element associations for different mineralization types: Au, Bi, Ag, Pb, Mo, Zn have apparent correlativity, and Au, Bi, Ag, Pb have bigger coefficient of correlation in skarn type gold mineralization. Au, Bi, Ag, Cu, Sn, Mo, Pb have strong correlativity, and there are strong coefficient of correlation between Au and Bi, and Ag, Cu and Sn, Mo in fracture alteration type mineralization. According to distribution of primary halo and...
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