| 北山中部增生造山过程:构造变形和~(40)Ar-~(39)Ar年代学制约 |
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| 引用本文： | 宋东方,肖文交,韩春明,田忠华,李咏晨.北山中部增生造山过程:构造变形和~(40)Ar-~(39)Ar年代学制约[J].岩石学报,2018,34(7):2087-2098. |
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| 作者姓名： | 宋东方 肖文交 韩春明 田忠华 李咏晨 |
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| 作者单位： | 中国科学院地质与地球物理研究所岩石圈演化国家重点实验室;中国科学院地球科学研究院;中国科学院青藏高原地球科学卓越创新中心;中国科学院新疆生态与地理研究所新疆矿产资源研究中心;中国地质科学院地质研究所 |
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| 基金项目： | 国家重点研发计划（2017YFC0601206）、国家自然科学基金项目（41672219、41402196、41230207）和博士后基金特别资助（2015T80133）联合资助. |
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| 摘 要： | 北山造山带是诠释中亚造山带南缘增生构造过程的关键区域之一。北山中部变质杂岩及相关侵入岩经历了复杂变质变形作用,是解剖北山增生构造演化过程的关键。本文在详细野外观察基础上,结合显微构造变形和黑云母~(40)Ar-~(39)Ar年代学研究,厘定北山中部相关岩石的变质变形时限。北山中部岩石普遍经历了韧性剪切变形。4个样品的黑云母~(40)Ar-~(39)Ar坪年龄分别为323.1±3.6Ma、296.0±3.7Ma、261.2±3.1Ma和209.2±4.0Ma,具有自北向南逐渐变年轻的特征。结合区域上岩石大地构造单元的展布特征,这些年龄反映了北山中部地区古生代至早中生代古洋壳(牛圈子洋盆)向北俯冲、造山带往南增生的过程。北山最晚的增生造山事件可能延续到三叠纪。
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| 关 键 词： | 北山造山带 构造变形 40Ar-39Ar年代学 晚古生代-早中生代 俯冲增生极性 |
| 收稿时间： | 2018/1/15 0:00:00 |
| 修稿时间： | 2018/4/22 0:00:00 |
Accretionary processes of the central segment of Beishan: Constraints from structural deformation and 40Ar-39Ar geochronology |
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| SONG DongFang,XIAO WenJiao,HAN ChunMing,TIAN ZhongHua and LI YongChen.Accretionary processes of the central segment of Beishan: Constraints from structural deformation and 40Ar-39Ar geochronology[J].Acta Petrologica Sinica,2018,34(7):2087-2098. |
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| Authors: | SONG DongFang XIAO WenJiao HAN ChunMing TIAN ZhongHua and LI YongChen |
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| Institution: | State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Sciences, Chinese Academy of Sciences, Beijing 100029, China,State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Sciences, Chinese Academy of Sciences, Beijing 100029, China;CAS Center for Excellence in Tibetan Plateau Earth Science, Chinese Academy of Sciences, Beijing 100029, China;Xinjiang Research Center for Mineral Resources, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China,State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Sciences, Chinese Academy of Sciences, Beijing 100029, China;CAS Center for Excellence in Tibetan Plateau Earth Science, Chinese Academy of Sciences, Beijing 100029, China,Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China and State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Sciences, Chinese Academy of Sciences, Beijing 100029, China |
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| Abstract: | The Beishan Orogenic Belt is a key area for understanding the accretionary tectonics of the southern Central Asian Orogenic Belt. The pervasively deformed metamorphic complexes and associated intrusive rocks from the central segment of Beishan are keys to illuminating the accretionary history of Beishan Orogenic Belt. In order to put constraints on the timing of metamorphism-deformation for the rocks in the central Beishan, this study carried out field geological, microstructural and 40Ar-39Ar geochronological studies on these rocks. The rocks from the central Beishan have undergone widespread ductile shearing deformation. Biotite 40Ar-39Ar dating on four samples yield respective plateau ages of 323.1±3.6Ma, 296.0±3.7Ma, 261.2±3.1Ma and 209.2±4.0Ma, which are younging from the north to the south. Combined with the spatial-temporal distribution of major litho-tectonic units, these data reveal a northward subduction of oceanic plate (Niujuanzi Ocean) and southward accretion of the orogen during the Paleozoic-Early Mesozoic in the central segment of Beishan. The last orogenic pulse of the Beishan may have extended to the Triassic. |
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| Keywords: | Beishan Deformation 40Ar-39Ar chronology Late Paleozoic-early Mesozoic Subduction-accretion polarity |
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