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宫忽洞是内蒙古中部的一例典型矽卡岩型铜矿床,位于华北板块北缘中段中元古代白云鄂博裂谷带内,赋存于矿区东南部花岗斑岩与白云鄂博群呼吉尔图组结晶灰岩形成的矽卡岩中。矿体呈透镜状、似层状分布,主要金属矿物为黄铜矿、斑铜矿、闪锌矿、辉铜矿、黄铁矿、磁黄铁矿等,脉石矿物为石榴石、透辉石、方解石、萤石等,矽卡岩类主要为透辉石-石榴石矽卡岩。花岗斑岩LA-ICP-MS锆石U-Pb年龄为(299.6±1.7)Ma,推断宫忽洞铜矿床是晚古生代构造岩浆活动的产物。花岗斑岩高Si、贫Al;亏损Ba、Sr、P、Ti等元素;10000Ga/Al值变化于2.32~3.49;稀土配分曲线呈典型的“V”字形;Fe OT/Mg O值介于9.86~12.27;其成因类型为A1亚类的A型花岗岩,可能形成于后造山拉张构造环境。3件热液方解石δ13CV-PDB值介于-10.6‰~-8.6‰,对应的δ18OV-SMOW值为4.6‰~15‰,宫忽洞铜矿床成矿期的CO2可能由花岗斑岩与灰岩地层的相互作用形成。4件不同硫化物的δ34S值介于1.2‰~10‰,表明成矿所需的硫可能来自于岩浆硫与海相硫酸盐的混合;4件不同硫化物的206Pb/204Pb=17.706~17.828,207Pb/204Pb=15.506~15.564;208Pb/204Pb=37.841~37.969,表明后造山阶段拉张环境形成的A型花岗斑岩体可能是成矿物质的主要提供者。
Gonghudong Cave is a typical skarn copper deposit in central Inner Mongolia. It is located in the Mesoproterozoic Neoproterozoic Bayan Obo rift zone in the middle margin of the northern margin of the North China Plate and occurs in Hujil maps of the granite porphyry and Bayan Obo Group Group of crystalline limestone formed in skarn. The ore bodies are lenticular in shape and distributed like strata. The main metal minerals are chalcopyrite, bornite, sphalerite, chalcopyrite, pyrite and pyrrhotite. The gangue minerals are garnet, Stone, calcite, fluorite, skarn mainly diopside - garnet skarn. The LA-ICP-MS zircon U-Pb age of granite porphyry is (299.6 ± 1.7) Ma, suggesting that the Gonghudong copper deposit is the product of Late Paleozoic tectonic magmatism. The granitic porphyry is characterized by high Si and poor Al depletion; depletion of elements such as Ba, Sr, P and Ti; 10000Ga / Al variation from 2.32 to 3.49; Rare earth distribution curve is typical “V” Ranging from 9.86 to 12.27. Type A granites whose genetic type is A1 subtype may be formed in the post-orogenic extensional tectonic setting. The δ13CV-PDB value of the three hydrothermal calcites ranges from -10.6 ‰ to -8.6 ‰, and the corresponding δ18OV-SMOW values range from 4.6 ‰ to 15 ‰. The mineralization period of Gongyongdong copper deposit may be characterized by granite porphyry and Limestone formation formation interaction. The δ34S value of four different sulfides ranged from 1.2 ‰ to 10 ‰, indicating that the sulfur needed for ore-forming may come from the mixture of magmatic sulfur and marine sulfate. The 206Pb / 204Pb of four different sulfides is between 17.706 and 17.828, 207Pb / 204Pb = 15.506 ~ 15.564; 208Pb / 204Pb = 37.841 ~ 37.969, indicating that the A-type granite porphyry formed in the post-orogenic phase of extension may be the main provider of ore-forming materials.