| 大陆中洋壳俯冲增生杂岩带特征与识别的重大科学意义 |
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| 引用本文： | 潘桂棠,肖庆辉,张克信,尹福光,任飞,彭智敏,王嘉轩.大陆中洋壳俯冲增生杂岩带特征与识别的重大科学意义[J].地球科学,2019,44(5):1544-1561. |
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| 作者姓名： | 潘桂棠 肖庆辉 张克信 尹福光 任飞 彭智敏 王嘉轩 |
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| 作者单位： | 1.中国地质调查局成都地质调查中心, 四川成都 610081 |
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| 基金项目： | 中国地质调查局地质调查项目DD2016-0345中国地质调查局地质调查项目DD20179386中国地质调查局地质调查项目DD20190375中国地质调查局地质调查项目DD20190053国家自然科学基金项目No.41772107 |
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| 摘 要： | 大洋或弧后洋盆俯冲增生是大陆地壳增长的主导地质作用.重建大陆中消亡的洋地层岩石组合序列是当代大陆动力学和地学研究的重大前沿.洋壳消减杂岩带的厘定是洋板块地质构造重建乃至全球大地构造研究之纲,是理解区域大地构造形成演化及动力学的核心.俯冲增生杂岩带的基本特征:(1)俯冲增生杂岩带物质组成的共性是:以强烈构造变形洋底沉积的硅质岩-硅泥质岩-粉砂岩、凝灰岩;弧-沟浊积岩等为基质;以洋岛-海山灰岩-玄武岩及塌积砾岩,洋内弧残留岩块,超镁铁质蛇绿岩、绿片岩、蓝片岩等为岩块.(2)变形样式:同斜倒转冲断叠瓦构造、增生柱前缘重力滑动构造以及泥质岩的底辟构造;增生楔前缘变形和增生形式受控于大洋或弧后洋盆的规模和洋壳的俯冲速度,也取决于陆缘碎屑供给量及洋底沉积厚度和岩性.(3)宽度和厚度:厚常达几千米,宽达几十公里至数百公里,延长上千公里,是洋壳俯冲消亡过程洋盆地层系统及陆缘沉积物加积的结果.(4)形成机制:是大陆碰撞前大洋(或弧后洋盆)岩石圈俯冲消减的产物.结合带中的早期俯冲增生杂岩带往往卷入晚期的构造混杂作用.
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| 关 键 词： | 俯冲增生杂岩 混杂岩 大陆地壳增长 洋板块地质 区域大地构造 构造地质 |
| 收稿时间： | 2019-02-21 |
Recognition of the Oceanic Subduction-Accretion Zones from the Orogenic Belt in Continents and Its Important Scientific Significance |
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| Pan Guitang,Xiao Qinghui,Zhang Kexin,Yin Fuguang,Ren Fei,Peng Zhimin,Wang Jiaxuan.Recognition of the Oceanic Subduction-Accretion Zones from the Orogenic Belt in Continents and Its Important Scientific Significance[J].Earth Science-Journal of China University of Geosciences,2019,44(5):1544-1561. |
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| Authors: | Pan Guitang Xiao Qinghui Zhang Kexin Yin Fuguang Ren Fei Peng Zhimin Wang Jiaxuan |
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| Affiliation: | (Chengdu Center of Geological Survey,China Geological Survey,Chengdu 610081,China;China Geological Survey,Beijing 100037,China;School of Earth Sciences,China University of Geosciences,Wuhan 430074,China) |
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| Abstract: | Oceanic subduction-accretion or back-arc oceanic subduction-accretion is the dominant geological process of continental crustal growth. Reconstructing the gradual extinction oceanic rock assemblage sequence of continent is a frontier of contemporary continental dynamics and geosciences. The determination of the oceanic crust subduction complex belt is the core of the reconstruction for the oceanic geological structure and the research of the global geotectonics, which is the core of the understanding for the evolution and dynamics of the regional geotectonics. Basic characteristics of the subduction accretion belt include:(1) the commonality of the material composition of the subduction accretionary complex:the pelagic siliceous rock, siliceous mudstone, siltstone, arc-trench turbidite as matrix, in highly tectonic deformation. Stratigraphic sequences of oceanic islands and seamounts are comprised of limestone and basalt, slided conglomerate, residual rock of intra-arc; ultramafic serpentine rocks, greenschists, and blueschists as mass. (2) Deformation style:synclinal overturned thrust imbricated structure, the gravity sliding structure of the accretionary prim front and the diapir structure of the argillaceous rock. The deformation and accretion form of the accretionary wedge front are controlled by the scale of oceanic crust or back-arc oceanic basina, and the subduction speed also depends on the amount of continent margin debris and the sediment thickness and lithology of ocean floor. (3) Width and thickness:the thickness is often several kilometers, the width is from several tens of kilometers to hundreds of kilometers, and the extension is thousands of kilometers. It is the result of the accumulation of oceanic basin system and continental margin sediments during the subduction of oceanic crust. (4) Formation mechanism:it is the product of the subduction of the lithosphere before the collision of the continent or back-arc oceanic basin. The early subduction accretionary belts in the jointing belt are often involved in late tectonic mélange. |
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| Keywords: | subduction-accretion complexes melange continental crustal growth oceanic plate geology regional geotectonics tectonics |
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