| 北祁连中段加里东俯冲－增生杂岩/火山弧带及其变形特征 |
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| 引用本文： | 张建新,许志琴.北祁连中段加里东俯冲－增生杂岩/火山弧带及其变形特征[J].地球学报,1995,16(2):153-163. |
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| 作者姓名： | 张建新 许志琴 |
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| 作者单位： | 中国地质科学院地质研究所，北京;中国地质科学院地质研究所，北京 |
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| 摘 要： | 分布于北祁连造山带中段的加里东期俯冲－增生杂岩／火山弧带可划分为托莱山俯冲杂岩带和走廊南山增生杂岩／火山弧带两个亚带。前者主要由蛇绿岩、蛇绿混杂岩及深海复理石组成，为古祁连洋俯冲作用后期由于岛弧的阻力在浅部刨铲作用的产物；后者由不完整的蛇绿岩透镜体、高压变质岩、弧火山岩及一些变质碎屑岩等组成，反映古祁连洋不断向北俯冲，火山弧前锋南移，增生杂岩不断增厚且在其下部发生板底垫托作用以及海沟不断向南倒退的复杂演化历史。俯冲－增生杂岩在加里东期共经历三期变形作用（Ｄ＿１、Ｄ＿２、Ｄ＿３）。Ｄ＿１、Ｄ＿２为简单剪切变形机制，反映从Ｎ向Ｓ的逆冲方向。Ｄ＿３为压扁型变形机制，代表走廊南山古岛弧与中祁连地块碰撞时的挤压变形。
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| 关 键 词： | 俯冲—增生杂岩／火山弧带 刨铲作用 板底垫托作用 走廊南山古岛弧 北祁连造山带 |
Caledonian Subduction-Accretionary Conplec/Volcanic Arc Zone and Its Deformation Features in the Middle Sector of North Qilian Mountains |
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| ZHANG Jian-xin and XU Zhi-qin.Caledonian Subduction-Accretionary Conplec/Volcanic Arc Zone and Its Deformation Features in the Middle Sector of North Qilian Mountains[J].Acta Geoscientia Sinica,1995,16(2):153-163. |
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| Authors: | ZHANG Jian-xin and XU Zhi-qin |
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| Institution: | Institute of Geology, CAGS, Beijing;Institute of Geology, CAGS, Beijing |
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| Abstract: | The Caledonian subduction-accretionary complex/volcanic zone,which located in the middie sec-tor of North Qilian Mountains,can be falled into Tuolaishan subduction complex zone and Zhoulang-nanshan accretionary complex/volcanic zone. The former consists of ophiolites,ophioIite melangesand abyssal flysches,which are preducts of offscraping during late peried of sueduction of ancient Qil-ian Ocean.The later,including residual ophiolite lens,high-pressure metamorphic rocks,arc volcanic rocks and metamorphic clastic rocks,displays the complicated evolution hist0ry which ancient Qilian Ocean subducted to the north,the frontier of volcanic arc moved to the south,the accretionary com-plex thickened and underplated successively and ancient ocean trench retreated to the south. Subeuc-tion-accretionary complexes experienced three stage deformations(D_1,D_2, D_3)during caledonian pori-od. D_1 and D_2,deformation mechanisms of simple shcar, indicate thrusting from N(NE)to S (SW),D_3,a deformation mechanism of flattening,shows compressive deformation of collision of Zhoulang-nanshan ancient island arc with Qilian block. |
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| Keywords: | subduction-accretionary complex/volcanic arc zone offscraping underplatingnorth Qilianmountains |
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