| 东昆仑造山带索拉沟地区三叠纪赞岐质闪长岩的成因机制及其对古特提斯造山作用的启示 |
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| 引用本文： | 王巍,熊富浩,马昌前,陈越,黄虎. 东昆仑造山带索拉沟地区三叠纪赞岐质闪长岩的成因机制及其对古特提斯造山作用的启示[J]. 地球科学, 2021, 46(8): 2887-2902. DOI: 10.3799/dqkx.2020.270 |
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| 作者姓名： | 王巍 熊富浩 马昌前 陈越 黄虎 |
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| 作者单位： | 1.成都理工大学地球科学学院, 四川成都 610059 |
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| 基金项目： | 国家自然科学基金项目41602049国家自然科学基金项目41972066 |
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| 摘 要： | 具有特殊成因机制的赞岐岩是探究深部岩浆动力学过程与区域构造演化的重要岩石探针之一.以东昆仑索拉沟地区赞岐质闪长岩为研究对象,开展系统的岩石学、年代学、元素地球化学和Lu-Hf同位素分析,厘定其岩石成因,揭示其对古特提斯造山作用的启示.锆石U-Pb年代学分析表明,索拉沟闪长岩形成于中三叠世(～243 Ma).岩石具有较低...
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| 关 键 词： | 东昆仑 三叠纪 高镁闪长岩 赞岐岩 古特提斯 地球化学 地质年代学 |
| 收稿时间： | 2020-08-16 |
Petrogenesis of Triassic Suolagou Sanukitoid-like Diorite in East Kunlun Orogen and Its Implications for Paleo-Tethyan Orogeny |
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| Wang Wei,Xiong Fuhao,Ma Changqian,Chen Yue,Huang Hu. Petrogenesis of Triassic Suolagou Sanukitoid-like Diorite in East Kunlun Orogen and Its Implications for Paleo-Tethyan Orogeny[J]. Earth Science-Journal of China University of Geosciences, 2021, 46(8): 2887-2902. DOI: 10.3799/dqkx.2020.270 |
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| Authors: | Wang Wei Xiong Fuhao Ma Changqian Chen Yue Huang Hu |
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| Abstract: | Sanukitoid with special genetic mechanism is one important petrological probe to study the magma dynamic processes and associated tectonic process. In this study, it presents petrology, geochronology, elemental geochemistry and Lu-Hf isotopic data on the Suolagou sanukitoid-like diorite in East Kunlun, aiming to characterize its petrogenesis and to reveal its implications on the Paleo-Tethyan orogeny. Zircon U-Pb dating shows that the Suolagou diorite was formed in the Middle Triassic (~243 Ma). Geochemically, they have low contents of SiO2(50.26%-57.40%), but high contents of total alkaline (Na2O+K2O=3.5%-6.3%), MgO (6.0%-7.1%) and high Mg# (50.1-60.9), belonging to high magnesium, calc-alkaline and metaluminous series. The Suolagou diorites show geochemical similarities to high Mg# andesitic sanukitoids with high contents of Sr (622×10-6-1 041×10-6), Cr (30×10-6-161×10-6) and Ni (19×10-6-79×10-6), and moderate contents of Y(7.6×10-6-24.3×10-6) and Yb(0.62×10-6-1.87×10-6). These rocks display remarkable enrichment in light rare earth elements and large-ion lithophile elements (such as Cs, Rb, K and Pb) but depletion in high-field strength elements (such as Ta, Nb and Zr), resembling the arc-related magmatic rocks above subduction zone. Lu-Hf isotopes show that the Suolagou diorites were derived from partial melting of enriched lithospheric mantle (εHf(t)=-2.4 to -0.4, TDM=0.89-0.99 Ga). The~243 Ma sanukitoid-like diorite in East Kunlun were formed in a continental arc setting, i.e., the parent magma derived from partial melting of enriched lithospheric mantle, subsequently followed by fractional crystallization of amphibole and biotite. This study suggests that the transition from Paleo-Tethyan oceanic slab subduction to terranes collision in East Kunlun occurred at Middle Triassic, and the Suolagou sanukitoid-like high-Mg diorites could be the magmatic response to the slab break-off at the end of subduction. |
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