新疆肯登高尔铜钼矿区侵入岩年代学、地球化学及其大地构造意义

发布时间：2018-03-18 08:02

本文选题：LA-ICP-MS锆石U-Pb定年　切入点：二长花岗岩　出处：《地质学报》2017年11期 　论文类型：期刊论文

【摘要】：肯登高尔铜钼矿床是新疆西天山博罗科努成矿带中一处矽卡岩型矿床,矿体赋存于纳林果勒中酸性侵入体与上石炭统东图津河组钙质粉砂岩夹碳酸盐岩的接触带上。纳林果勒岩体主要由花岗闪长岩与二长花岗岩组成。通过LA-ICP-MS锆石U-Pb同位素定年,获得花岗闪长岩和二长花岗岩的加权平均年龄分别为316.3±3.5Ma和298.9±3.3Ma,表明两者侵位时代分别为晚石炭世和早二叠世。地球化学组成上花岗闪长岩具有高硅和高钠的特征,富集Sr、Rb和Th,亏损Nb、Ta、Yb和Y,无Eu异常,岩石具有埃达克岩的特征,是造山晚期加厚下地壳部分熔融的产物。二长花岗岩具有富硅、富钾、低铝的特征,富集Rb、Th、Nb和Hf,亏损Sr、Ta和Ti,具有明显Eu负异常,岩石为高分异I型花岗岩,是岩石圈伸展减薄背景下,下地壳进一步熔融形成的基性岩浆通过分离结晶作用形成的产物。结合成岩年龄和区域构造背景,推测西天山北缘在晚石炭世进入碰撞造山阶段,在早二叠世向造山后伸展阶段过渡。
[Abstract]:The Kendenggaer Cu-Mo deposit is a skarn type deposit in the Borokonu metallogenic belt of western Tianshan, Xinjiang. The orebody occurred in the contact zone between the middle acid intrusion of Nalinggol and the calcareous siltstone intercalated carbonate rocks of the Upper Carboniferous East Tujin River formation. The Nalinggol rock body is mainly composed of granodiorite and monzogranite. The zircon U-Pb isotopic dating of the LA-ICP-MS zircon is used. The weighted mean ages of granodiorite and monzodiorite are 316.3 卤3.5 Ma and 298.9 卤3.3 Ma, respectively, indicating that the emplacement ages are late Carboniferous and early Permian, respectively. The geochemical composition of granodiorite is characterized by high silicon and high sodium. The rocks are rich in Sr ~ (2 +) RB and Th, depleted in NB ~ (+) T _ (+) T _ (2) Yb and Y, no EU anomaly, and have the characteristics of adakite, which is the product of partial melting of lower crust in late orogenic period, and is characterized by rich in silicon, rich in potassium and low in aluminum. It is rich in RB Th, NB and HF, depleted in Sr, Ta and Ti, and has obvious negative EU anomalies. The rocks are highly differentiated I-type granites, which are in the lithospheric extensional thinning setting. The basic magma formed by further melting of the lower crust was formed through separation and crystallization. Combining with the diagenetic age and regional tectonic setting, it is inferred that the northern margin of the West Tianshan Mountains entered the collision orogenic stage in the late Carboniferous. The transition from early Permian to post-orogenic extension.
【作者单位】：中国地质大学(北京)地球科学与资源学院;中国地质大学(北京)地质过程与矿产资源国家重点实验室;新疆维吾尔族自治区地质勘察基金项目管理中心;中国冶金地质总局中南局西北发展集团;
【基金】：国家自然科学基金项目(编号41572062、U1303292、41302064) 中央返还两权价款资金综合研究项目(编号Y15-LQ04) 国家科技支撑计划项目(编号2011BAB06B02-02)联合资助成果
【分类号】：P588.12;P618.41;P618.65

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