东准噶尔希勒库都克钼矿含矿岩体的成因及区域矿床对比研究

发布时间：2018-05-27 18:03

  本文选题：东准噶尔 + 钼矿　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：希勒库都克钼矿位于东准噶尔北缘,是东准噶尔出现的唯一一个斑岩型钼矿。矿区主要侵入体为闪长玢岩、二长花岗岩、花岗斑岩及石英斑岩。其中钼矿主要与准铝质-弱过铝质的钙碱性-高钾钙碱性的花岗斑岩及二长花岗岩有关。含矿花岗岩类属于I型花岗岩。石英斑岩、花岗斑岩及二长花岗岩的锆石的U-Pb年龄分别为315.7±2.3 Ma、326.4±2.0 Ma、328.2±1.8Ma,形成于早石炭世晚期的后碰撞环境当中。二长花岗岩、花岗斑岩以及石英斑岩均具有相似的?Hf(t)值及年轻的二次模式年龄,其中?Hf(t)值分别为11.5-15.5、12.7-15.1、12.3-15.6,平均值分别13.9、14.1、14.0,二次模式年龄分别为388-601Ma、379-524Ma、328-545Ma,平均值分别为451Ma、435Ma、432Ma。二长花岗岩锆石δ18O值为4.89-5.26、平均为5.03,花岗斑岩锆石δ18O为4.84-5.18、平均值为5.07,石英斑岩锆石δ18O值为4.29-5.08、平均值为4.85,含矿花岗岩与地幔中锆石δ18O保持一致。矿区含矿岩体具有相似的微量、稀土元素分配图及同位素特征,并且其主要元素在哈克图解上显示有规律的变化,说明矿区含矿岩体来源于同一个没有被蚀变的年轻洋壳的部分熔融形成的岩浆连续演化产物,而没有古老地壳及沉积物的加入。石英斑岩与含矿岩体具有相似的Hf同位素特征及时空上的紧密性,判断其为与含矿岩体同一源区而不同背景下的产物。锆石Ti温度计算出来的岩石结晶温度分别为:二长花岗岩为568-825℃、平均为728℃,花岗斑岩为:615-745℃、平均为719℃,石英斑岩为686-878℃,平均为777℃。二长花岗岩中锆石CeIV/CeIII比值为25.61-141.45、平均值为71,岩体氧逸度为-7.5至-21.04、平均值为-12.20,花岗斑岩中锆石CeIV/CeIII比值38-147.5、平均值为95,氧逸度为-8.62至-18.84之间、平均值为-12.80。贫矿石英斑岩中锆石CeIV/CeIII比值6.21-42.77、平均值为23.97,氧逸度在-13.92到-19.02之间、平均值为-16.73。说明矿体形成于较高氧逸度条件下。希勒库都克钼矿含矿岩体形成于较高氧逸度条件下,而与中亚造山带其他大型-超大型斑岩矿床相比,其氧逸度相对较低,说明希勒库都克矿床大小可能被其源区氧逸度大小所控制。
[Abstract]:The Shilakuk molybdenum deposit is located in the northern margin of East Junggar and is the only porphyry molybdenum deposit in East Junggar. The main intrusions are diorite porphyrite, monzogranite, granitic porphyry and quartz porphyry. The molybdenum ore is mainly related to the granitic porphyry and monzomorphic granitic porphyry with quasi-aluminite and weak peraluminous and high potassium calc-alkaline. The ore-bearing granites belong to type I granites. The U-Pb age of zircon from quartz porphyry, granitic porphyry and monzomorphic granite is 315.7 卤2.3 Ma-326.4 卤2.0 Ma-328.2 卤1.8 Ma. it was formed in the post-collision environment of late early Carboniferous. The monzomorphic granite, granitic porphyry and quartz porphyry have similar values of HfTO) and young secondary model age, among them, the values of HfTX) are 11.5-15.5U 12.7-15.112.3-15.6, the mean values are 13.9U 14.1U 14.0, and the secondary model ages are 388-601Ma379-524Ma328-545Ma.The average values are 451Ma-435Ma435Ma432Ma. the average values of the two types of granite are 11.5-15.55-15.112.3-15.60.The secondary model ages are 388-601Ma379-524Ma328-545Ma. the average values are 451Ma435Ma432Ma. The zircon 未 18O value of the monzogranite is 4.89-5.26, the average is 5.03, the zircon 未 18O of granitic porphyry is 4.84-5.18, the average is 5.07, the 未 18O value of quartz porphyry zircon is 4.29-5.08, the average value is 4.85. The zircon 未 18O of ore-bearing granite is consistent with 未 18O in mantle. The ore-bearing rock bodies in the mining area have similar trace, rare earth element distribution maps and isotopic characteristics, and their main elements show regular changes in the Huck diagram. The results show that the ore-bearing rock bodies in the ore area are derived from the continuous magmatic evolution of the same partially melted young oceanic crust without alteration without the addition of the ancient crust and sediments. Quartz porphyry and ore-bearing rock bodies have similar HF isotopic characteristics and spatio-temporal compactness, which are determined to be the products of different backgrounds in the same source area as the ore-bearing rock bodies. The crystallization temperatures calculated by zircon Ti temperature are 568-825 鈩，

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