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宜里钼矿为大兴安岭北段新发现的具大型钼找矿潜力的中型钼矿床,赋矿围岩为晚古生代花岗岩和卧都河组地层,矿区深部发现有晚期花岗斑岩脉,其成矿可与“体中体”模式对比。矿区内晚期花岗岩(黑云母花岗岩和花岗斑岩)岩石地球化学表明,岩石具有高SiO2、富K2O+Na2O和相对高的Al2O3,低MgO、TFeO、CaO的特征,K2O/Na2O=0.76～1.27,A/CNK=1.02～1.23;微量元素富集Rb、U、K、Pb等LILE,相对亏损Nb、Ta、Ti、P和LREE等HFSE,(La/Yb)N=11.09～22.41,重稀土明显亏损,无或弱Eu异常(δEu=0.63～0.92),且具低Ni、Cr含量和Mg#,高Sr/Y比值,显示出埃达克质岩石地球化学亲和性。LA-MC-ICP-MS锆石U-Pb同位素精细年代学测试结果显示,矿区内晚期花岗岩的侵位年龄集中在132.43±0.61～134.46±0.58Ma,属早白垩世。辉钼矿Re-Os同位素定年显示,成矿年龄为131.8±1.5Ma,较岩体侵位年龄晚2.7～0.6Ma。结合熔融实验和区域资料,矿区埃达克岩为挤压向伸展转换的构造体制下加厚下地壳部分熔融的产物,而钼成矿作用的触发机制主要是埃达克质岩浆出熔后,残余的加厚下地壳的拆沉作用,推测矿区深部存在与成矿直接相关的花岗质岩体。大兴安岭北段存在有4期钼成矿事件,分别为加里东早期(510～470Ma)、华力西晚期(300～290Ma)、印支晚期—燕山早期(205～175Ma)、燕山中期早阶段晚侏罗世(150～145Ma)和晚阶段早白垩世(143～129Ma)。其中,印支晚期—燕山早期(大兴安岭北段西坡)和燕山中期(大兴安岭北段东坡)为成矿高峰期。宜里钼矿即为大兴安岭北段成矿高峰期燕山中期晚阶段的产物。
The Yuli molybdenum deposit is a newly discovered medium-sized molybdenum deposit with large-scale molybdenum potential for prospecting in the northern part of the Greater Hinggan Mountains. The ore-hosting rocks are late Paleozoic granite and lying Duhehe formation. Late granite porphyry veins were found in the ore area, Mine can be compared with the “body” mode. The rock geochemistry of late granites (biotite granites and granite porphyries) in the mines indicates that the rocks are characterized by high SiO2, rich K2O + Na2O and relatively high Al2O3, low MgO, TFeO, CaO with K2O / Na2O = 0.76 ~ 1.27 (A / CNK = 1.02-1.23). Trace elements are enriched in LILE such as Rb, U, K and Pb, and relatively depleted in HFSE such as Nb, Ta, Ti, P and LREE, with (La / Yb) N = 11.09-22.41, Obvious depletion, no or weak Eu anomaly (δEu = 0.63-0.92), low Ni, Cr content and Mg #, high Sr / Y ratios, indicating the geochemical affinity of adakitic rocks. The results of LA-MC-ICP-MS zircon U-Pb isotopic dating show that the emplacement age of late granites in the mining area is concentrated in the range of 132.43 ± 0.61 ~ 134.46 ± 0.58Ma, belonging to the Early Cretaceous. Re-Os isotopic dating of molybdenite shows that the metallogenic age is 131.8 ± 1.5Ma, which is 2.7 ~ 0.6Ma later than the emplacement age of the rock mass. According to the melting experiment and regional data, the adakite in the mining area is a product of partial thickening of the lower crust under the tectonic regime of compression-extension conversion. The triggering mechanism of molybdenum mineralization is mainly that after the adakitic magma is melted out of the melt, Remnant thickened lower crust delamination, presumably there is a granitic rock mass directly related to metallogenesis in the deep of the mining area. There are four molybdenum metallogenic events in the northern segment of Daxinganling, which are respectively from the early Caledonian period (510-470 Ma), the late Variscan period (300-290 Ma), the late Indosinian period (205-175 Ma), the late Yanshan middle period Jurassic (150 ~ 145Ma) and late stage Early Cretaceous (143 ~ 129Ma). Among them, the late Indosinian - the early Yanshan (Daxinganling northern slope) and mid-Yanshan (Daxinganling northern slope) is the peak of mineralization. Yili molybdenum mine is the northern section of the Greater Xing’an Mountains Yanshan peak during the late stage of the product.