| 新疆北部阿尔泰山东段泥盆纪岩浆活动及侵位方式的探讨 |
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| 引用本文： | 蔺新望,王星,陈光庭,赵端昌,赵江林.新疆北部阿尔泰山东段泥盆纪岩浆活动及侵位方式的探讨[J].现代地质,2020,34(3):514-531. |
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| 作者姓名： | 蔺新望 王星 陈光庭 赵端昌 赵江林 |
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| 作者单位： | 1.陕西省矿产地质调查中心,陕西 西安 7100682.陕西省地质调查院,陕西 西安 7100543.青海省地质调查院,青海 西宁 810012 |
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| 基金项目： | 新疆地勘基金中心项目“新疆富蕴县阿拉一带1∶5万L45E003023等五幅区域地质调查”(A16-1-LQ01);陕西省公益性地质调查项目“陕西省安康市老县等四幅1∶5万区域地质矿产调查”(20180101) |
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| 摘 要： | 新疆北部阿尔泰山东段发育大量的岩浆岩,对取自阿德尔石英闪长斑岩和乔拉克萨依花岗闪长岩的样品进行了LA-ICP-MS锆石U-Pb同位素年龄测定,获得了(415.7±4.0) Ma和(413.5±3.0) Ma的年龄值。据此将其形成时代厘定为早泥盆世。两组样品主量元素差异明显,稀土、微量元素特征基本一致。石英闪长斑岩具有中钾-低钾钙碱性、过铝质花岗岩岩石特征,而花岗闪长岩具有高钾钙碱性、准铝质系列特征。两者轻稀土富集、重稀土相对亏损,中等-弱负Eu异常;微量元素Rb、Th、U等LILE富集,具有明显的"峰",Nb、Ta、Ti等HFSE强烈亏损,呈明显"TNT"负异常,显示了与俯冲作用有关的岩浆岩特征。综合区域地质资料分析,阿尔泰造山带东段泥盆纪早期岩浆活动剧烈,成因复杂,侵位方式多样,形成了多种火成岩构造组合,可能是热幔-热壳结构下的产物,具有形成超大型矿床的潜力。
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| 关 键 词： | 早泥盆世 洋壳俯冲 热幔-热壳 阿尔泰山东段 新疆北部 |
| 收稿时间： | 2018-06-25 |
| 修稿时间： | 2019-12-15 |
Magmatic Activity and Emplacement of the Devonian Intrusive Rocks in Eastern Altay,Northern Xinjiang |
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| LIN Xinwang,WANG Xing,CHEN Guangting,ZHAO Duanchang,ZHAO Jianglin.Magmatic Activity and Emplacement of the Devonian Intrusive Rocks in Eastern Altay,Northern Xinjiang[J].Geoscience——Journal of Graduate School,China University of Geosciences,2020,34(3):514-531. |
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| Authors: | LIN Xinwang WANG Xing CHEN Guangting ZHAO Duanchang ZHAO Jianglin |
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| Institution: | 1. Shaanxi Mineral Resources and Geological Survey, Xi’an, Shaanxi 710068, China2. Shaanxi Institute of Geological Survey, Xi’an, Shaanxi 710054, China3. Qinghai Geological Survey Institute, Xining, Qinghai 810012, China |
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| Abstract: | A large number of magmatic rocks were developed in the eastern Altay, northern Xinjiang. LA-ICP-MS zircon U-Pb dating indicates that the Adeer quartz diorite porphyry and Qiaolakesayi granodiorite were emplaced at (415.7±4.0) Ma and (413.5±3.0) Ma, respectively. These ages revealed that the rocks were emplaced in the Early Devonian. There are significant major-element geochemical differences between the two rock types, but their trace-element (including REE) features are largely similar.The quartz diorite porphyry is medium-low-K calc-alkaline and peraluminous, but the granodiorite is high-K calc-alkaline and metaluminous. The REE distribution patterns reveal that the rocks are LREE-enriched, HREE-depleted, and with strong LREE/HREE fractionation and weakly-moderately negative Eu anomalies. The rocks are enriched in LILEs (Rb, Th, U) and LREEs, and clearly depleted in HFSEs (Nb, Zr, Ti),Sr, and P,demonstrating a subduction-related affinity. Considering also the regional geology, we concluded that magmatism was active in the Early Devonian eastern Altay, and with complex petrogenetic cause and emplacement mode, which formed the various igneous rock assemblages in the region. This plutonism may have been the product of hot mantle and hot crustal structure, and has the potential to generate super-large deposits. |
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| Keywords: | Early Devonian oceanic crust subduction hot mantle and hot crustal structure eastern Altay northern Xinjiang |
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