| 大兴安岭北段地壳左行走滑运动的时代及其对中国东北及邻区中生代以来地壳构造演化重建的制约 |
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| 引用本文： | 李锦轶,莫申国,和政军,孙桂华,陈文.大兴安岭北段地壳左行走滑运动的时代及其对中国东北及邻区中生代以来地壳构造演化重建的制约[J].地学前缘,2004,11(3):157-168. |
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| 作者姓名： | 李锦轶 莫申国 和政军 孙桂华 陈文 |
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| 作者单位： | 中国地质科学院,地质研究所,北京,100037;中国地质科学院,地质研究所,北京,100037;中国科学院,地理科学与资源研究所,资源与环境信息系统国家重点实验室,北京,100101 |
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| 基金项目： | 国家自然科学基金项目 (4 9872 0 6 6，40 0 0 1 2 1 475 )，国土资源部国际合作与科技司项目 (992 0 2 3) |
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| 摘 要： | 中国东北及邻区 ,在中生代期间是否经历了大规模走滑运动而发生向东的逃逸和地壳加厚 ,是该区乃至碰撞造山带后碰撞地壳构造演化的一个重要问题。在对已有资料的综合分析基础上 ,大兴安岭北段中生代以来的构造变形可以划分为四期 :( 1 )可能发生在侏罗纪晚期的向南逆冲推覆运动 ;( 2 )平行蒙古—鄂霍茨克造山带的左行韧性走滑剪切作用 ;( 3)切割上述韧性走滑剪切带和蒙古—鄂霍茨克造山带的向南东的逆冲断裂作用 ;( 4)新生代北北东走向的正断作用。根据时空展布和运动学特征 ,推测前两期变形与蒙古—鄂霍茨克造山带的形成演化有关 ,第三期变形与古太平洋板块在亚洲大陆下的俯冲有关 ,第四期变形与现今太平洋板块的俯冲有关。对采自第二期构造变形带内的同构造变质矿物黑云母的Ar Ar定年 ,获得了 1 2 7～ 1 30Ma的坪年龄和等时线年龄 ,据此确定该区地壳左行走滑运动的主要活动时期为白垩纪初期。这一研究成果与中国东北南部燕山地区走滑运动资料的结合 ,揭示出在白垩纪初期 ,中国东北及邻区地壳被向东挤出加厚。根据已有的区域地质资料 ,中国东北中生代以来地壳构造演化可以划分为 4个阶段 :( 1 )三叠纪期间与古亚洲洋关闭和杭盖—肯特洋及古太平洋收缩有关的地壳挤压与伸展变动 ;( 2 )侏罗纪至白垩纪初
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| 关 键 词： | 大兴安岭北段 构造变形 Ar-Ar定年 中国东北及邻区地壳演化 |
| 文章编号： | 1005-2321(2004)03-0157-12 |
| 修稿时间： | 2004年6月30日 |
The timing of crustal sinistral strike-slip movement in the northern Great Khing'an ranges and its constraint on reconstruction of the crustal tectonic evolution of NE China and adjacent areas since the Mesozoic |
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| LI Jin-yi,MO Shen-guo.The timing of crustal sinistral strike-slip movement in the northern Great Khing'an ranges and its constraint on reconstruction of the crustal tectonic evolution of NE China and adjacent areas since the Mesozoic[J].Earth Science Frontiers,2004,11(3):157-168. |
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| Authors: | LI Jin-yi MO Shen-guo |
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| Institution: | LI Jin-yi~1,MO Shen-guo~ |
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| Abstract: | Whether NE China and its adjacent areas underwent disturbance of a large-scale of strike-slip movement and led to crustal extrusion and thickening in the Mesozoic similar to Qinghai-Xizang plateau in the Cenozoic is an important issue both on crustal evolution of the areas and on post-collisional evolution of the collisional belt. Based on available geological data, the structural deformation since the Mesozoic in the northern Great Khing'an range may be divided into four episodes as follows: (1) southwards thrusting movement possibly in the end of the Jurassic; (2) sinistral strike-slip ductile shearing movement parallel to the Mongol-Okhotsk orogenic belt; (3) southeastwards brittle thrusting movement cutting off above structural and Mongol-Okhotsk belts; and (4) occurrence of NNE-extended normal faults in the Cenozoic. The first two periods of structural deformation are supposed to be related to the orogenic processes of Mongol-Okhotsk belt; the third one was response of the subduction of Paleo-Pacific (Kula-Pacific) plate under the Eurasia; and the youngest one was the result of subduction of the Pacific plate based on their spatial-temporal and kinematic features. Ar-Ar dating to syn-tectonic biotites from the second period of structural deformation belt yields spectrum and isochron ages of 127～130 Ma, implying that the peak timing of this period of tectonothermal event and crustal extrusion and thickening in NE China and its adjacent areas is in the beginning of the Cretaceous. The synthesis of available geological data indicates that the crustal tectonic evolution of NE China and adjacent areas since the Mesozoic may be reconstructed as four stages: (1) Triassic compression and extension originated from collision of Siberian and Sino-Korean continents and contracting evolution of Kanggai-Kente and Paleo-Pacific oceans; (2) rotation, strike-slipping, and thrusting of blocks, crustal thickening and extrusion from the Jurassic to the beginning of the Cretaceous following the closure of the Kanggai-Kente ocean and subduction of Paleo-Pacific oceanic plate under the Eurasia;(3)extension and thinning of the lithosphere and magmatic activities from the Cretaceous to the Paleocene due to subduction of Paleo-Pacific oceanic plate under the Eurasia; and (4) crustal disintegration and rifting associated with the subduction of the Pacific plate under the Eurasia since the Eocene. |
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| Keywords: | Northern Great Khing'an range structural deformation Ar-Ar dating tectonic evolution of NE China and its adjacent areas |
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