| 祁连山北缘—河西走廊西段晚新生代逆冲推覆断裂发育模式 |
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| 引用本文： | 陈柏林,王春宇,崔玲玲,刘建民.祁连山北缘—河西走廊西段晚新生代逆冲推覆断裂发育模式[J].地学前缘,2008,15(6). |
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| 作者姓名： | 陈柏林 王春宇 崔玲玲 刘建民 |
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| 基金项目： | 中国地质调查局地质调查项目
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| 摘 要： | 祁连山北缘—河西走廊西段地处青藏高原东北缘,是我国新构造活动最强烈的地区之一。通过野外对研究区主要活动断裂的调查研究、结合年代学测试和综合分析,认为祁连山北缘—河西走廊西段地区的旱峡—大黄沟断裂、玉门断裂、新民堡断裂和阴洼山断裂都是晚更新世至全新世活动断裂。旱峡—大黄沟断裂形成于中新世晚期,一直活动至今;玉门断裂形成于上新世早期,在距今7.6ka左右和3.2ka左右发生过2次强烈的新构造活动(古地震),也是2002年玉门地震的发震断裂;阴洼山断裂形成于上新世晚期(3.0Ma左右),在距今19.9～21.0ka、8.6～10.0ka、4.1～5.0ka发生过3次强烈的新构造活动,也可能是1785年惠民堡(现新民堡)地震的发震断裂;但是位于近盆地中心的新民堡断裂形成时代明显晚的多,起始于中更新世晚期(0.17Ma左右),在距今28.3ka、4.4ka和1.2ka左右发生过强烈的3次新构造活动。在运动形式上,上述4条断裂均为自南南西向北北东的逆冲推覆。在变形性质上,新民堡断裂以非地震性的蠕滑为主,其他3条断裂主要为地震性的粘滑变形。在祁连山北缘—河西走廊西段的北北东剖面上,逆冲推覆断裂表现为前展-后展复合发育模式,即形成时代最新的是位于酒西盆地中心的新民堡断裂,在酒西盆地中心以南部分的剖面中断裂发育为前展式,由祁连山腹地向河西走廊盆地中心断裂形成时代越来越新,而酒西盆地中心以北部分的剖面中断裂发育为后展式,即从盆地中心到盆地北缘断裂形成时代越来越老。
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| 关 键 词： | 活动断裂 晚新生代 逆冲推覆 发育模式 祁连山北缘—河西走廊西段 |
Developing model of thrust fault system in western part of nortern Qilian Mountains margin-Hexi Corridor basin during late Quaternary |
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| Chen Bailin,Wang Chunyu,Cui Lingling,Liu Jianmin.Developing model of thrust fault system in western part of nortern Qilian Mountains margin-Hexi Corridor basin during late Quaternary[J].Earth Science Frontiers,2008,15(6). |
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| Authors: | Chen Bailin Wang Chunyu Cui Lingling Liu Jianmin |
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| Abstract: | The western part of northern Qilian Mountains margin-Hexi Corridor basin,situated at the north-eastern margin of the Qinghai-Xizang plateau,is one of the areas where the neo-structural activity occurs most strongly in our country.By means of the field investigation and chronologic measurement of the main active faults in the area and analysis of other materials,the authors reached a new conclusion as follows.The Hanxia-Dahuanggou fault,the Yumen fault,the Yinwashan fault and the Xinminbao fault were all active during the late Quaternary(late Pleistocene and Holocene epoch).The Hanxia-Dahuanggou fault developed during the late Miocene epoch and has been being active till the present.The Yumen fault developed during the early period of Pliocene epoch,and there were twice strong neo-structural activities(paleo-earthquakes)taking place at about 7.6 ka BP and 3.2 ka BP.The fault was also the causative structure of Yumen earthquake in 2002.The Yinwashan fault developed during the late period of Pliocene epoch(about 3 Ma),and there were three strong neo-structural activities(paleo-earthquakes)occurring at about 19.9-21.0 ka BP,8.6-10.0 ka BP and 4.1-5.0 ka BP.The Yinwashan fault probably was the causative structure of the Huiminbao(now Xinminbao)earthquake in 1785.However,the forming age of the Xinminbao fault is much younger than those of above three faults,the fault developed during the late period of middle Pleistocene epoch(about 0.17 Ma)and three strong neo-structural activities(paleo-earthquakes)took place there at about 28.3 ka BP,4.4 ka BP and 1.2 ka BP.The sense of the movement of all the four faults is unanimously trusting from the south-western side(upside)to the north-east.The feature of the movement of the Xinminbao fault is the creeping deformation,but other faults move mainly in stick-slip mode.On the section,the thrust faults of western part of northern Qilian Mountains margin-Hexi Corridor developed on a composite model of progressive and retrogressive development.In other words,the youngest fault is the Xinminbao fault near the centre of the basin.The faults on the section south of the centre of the Western Jiuquan basin developed on a progressive developing model and the forming age of fault is becoming younger and younger from the hinterland of Qilian Mountain to the centre of the basin.While the faults on the section to the north of the centre developed on a retrogressive developing model and the forming age of fault is becoming older and older from the centre to the northern margin of the Western Jiuquan basin. |
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| Keywords: | active fault late Quaternary thrust developing model western part of northern Qilian Mountains margin-Hexi Corridor |
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