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1.
Late Cenozoic sediments in the Hexi Corridor, foreland depression of the Qilian Mountain preserved reliable records on the evolution of the Northern Tibetan Plateau. Detailed magnetic polarity dating on a 1150 m section at Wenshushan anticline in the Jiudong Basin, west of Hexi Corridor finds that the ages of the Getanggou Formation, Niugetao Formation and Yumen Conglomerate are >11-8.6 Ma, 8.6-4.5 Ma and 4.5-0.9 Ma respectively. Accompanying sedimentary analysis on the same section suggests that the northern Tibetan Plateau might begin gradual uplift since 8.6-7.6 Ma, earlier than the northeastern Tibetan Plateau but does not suppose that the plateau has reached its maximum elevation at that time. The commencement of the Yumen Conglomerate indicates the intensive tectonic uplift since about 4.5 Ma.
相似文献2.
FANG Xiaomin ZHAO Zhijun LI Jijun YAN Maodu PAN Baotian SONG Chunhui & DAI Shuang . Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China . Key Laboratory of Western China''''s Environmental Systems Ministry of Education & College of Resources Environment Lanzhou University Lanzhou China . College of Geography Nanjing Normal University Nanjing China 《中国科学D辑(英文版)》2005,48(7)
The uplift process of the Qinghai-Tibetan Plateau holds the key to understand the dynamic mechanisms of continental crust shortening and mountain-building and to test the relationship between the Tibetan uplift and tectonic-climatic coupling and environmental im-pacts[1―4].However,there are still many debates in the process and mechanism of how the Tibetan Plateau uplifted to the present configuration.Among various approaches to solve these key questions,dating of the Cenozoic stratigraphy … 相似文献
3.
The thick alluvial conglomerate sequences around the Tibetan Plateau have been notoriously difficult to date. Here we use the cosmogenic nuclide burial dating method to date the Yumen and Jiuquan formations, a ∼900 m thick fanglomerate found in the Hexi Corridor, the foredeep of the Qilian Shan, and exposed in the Laojunmiao anticline. We date 16 sites with simple burial dating and 2 sites with isochron burial dating, and use these dates to reinterpret the magnetostratigraphy of the section. We suggest that the bottom of the Yumen Formation, defined by a progressive unconformity, is around 5 My. Taking this timing as the initiation of anticline growth, the long-term crustal shortening rate at the ramp zone in western Qilian Shan is about 0.72 mm/yr, consistent with those obtained from middle and eastern Qilian Shan. The boundary between the Yumen and Jiuquan Formations is near ∼1.2 My. Three other angular unconformities are dated to ∼2.6–3.1, ∼2.2–2.5, and ∼1.2–1.7 My, respectively. Burial dating offers a robust chronology for these deposits, and when combined with paleomagnetic stratigraphy offers much tighter precision. 相似文献
4.
The vegetation and climate change during Neocene and Early Quaternary in Jiuxi Basin,China 总被引：14，自引：3，他引：11
MA Yuzhen FANG Xiaomin LI Jijun WU Fuli & ZHANG Jun . Key Laboratory of Western China’s Environmental Systems College of Resources Environment Lanzhou University Lanzhou China . State Key Laboratory of Loess Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China 《中国科学D辑(英文版)》2005,48(5):676-688
Desertification and aridification in the inland of Asia are the important scientific issues pertaining to the existing environment of mankind and the sustain-able development of society in western China. The onset and evolution sequence, development and proc-ess of history and the mechanism of this transition are thought to be one of the most attractive hot objects of research on climatic changes in the Northern Hemi-sphere during the Cenozoic, which may have involved glaciation in the North… 相似文献
5.
FU KaiDao FANG XiaoMin GAO JunPing HAN WenXia & LI LiLi MOE National Laboratory of Western China''''s Environmental Systems & College of Resource Environment Lanzhou University Lanzhou China Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2007,50(1):81-91
The widely distributed thick gravel deposits along the rim of the Tibetan Plateau have been long thought to be the product of rapid tectonic uplift of the plateau. However, this has been challenged by recent works that suggest these thick gravels may be the result of climate change. In this paper we carried out a detailed field measurement of gravel grain sizes from the Jiuquan and Gobi Gravel Beds in the top of the Laojunmiao section in the Jiuxi Basin in the northern margin of Qilian Mts. (northern Tibetan Plateau). The results suggest that the grain sizes of the Jiuquan and Gobi Gravel Beds over the last 0.8 Ma are characterized by nine coarse-fine cycles having strong 100-ka and 41-ka periodicities that correlate well with the loess-paleosol monsoon record and isotopic global climatic record from deep sea sediments as well as by a long trend of coarsening in gravel grain size. The coarse gravel layers were formed during the warm-humid interglaciations while the fine layers correspond to the cold-dry glaciations. Because the paleoclimate in NW China began to get dramatically drier after the mid-Pleistocene, we think the persistent coarsening of gravel grain size was most probably caused by the rapid uplift of the northern Tibetan Plateau, and that the orbital scale cyclic variations in gravel grain size were driven by orbital forcing factors that were superimposed on the tectonically-forced long-term coarsening trend in gravel size. These findings also shed new light on the interaction results of climate and tectonics in relation to the uplift of the Tibetan Plateau. 相似文献
6.
THE NORTHWARD GROWTH OF THE NORTHEASTERN TIBETAN PLATEAU IN LATE CENOZOIC: IMPLICATIONS FROM APATITE (U-Th)/He AGES OF LONGSHOU SHAN 
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下载免费PDF全文 Longshou Shan, located at the southern edge of the Alxa block, is one of the outermost peripheral mountains and the northeasternmost area of the northeastern Tibetan plateau. In recent years, through geochronology, thermochronology, magnetic stratigraphy and other methods, a large number of studies have been carried out on the initiation time of major faults, the exhumation history of mountains and the formation and evolution of basins in the northeastern Tibet Plateau, the question of whether and when the northeastward expansion of the northeastern Tibet Plateau has affected the southern part of the Alxa block has been raised. Therefore, the exhumation history of Longshou Shan provides significant insight on the uplift and expansion of the Tibetan plateau and their dynamic mechanism. The Longshou Shan, trending NWW, is the largest mountain range in the Hexi Corridor Basin, and its highest peak is more than 3 600m(with average elevation of 2800m), where the average elevation of Hexi Corridor is 1 600m, the relative height difference between them is nearly 2200m. This mountain is bounded by two parallel thrust faults: The North Longshou Shan Fault(NLSF)and the South Longshou Shan Fault(SLSF), both of them trends NWW and has high angle of inclination(45°~70°)but dips opposite to each other. The South Longshou Shan Fault, located in the northern margin of the Hexi Corridor Basin, is the most active fault on the northeastern plateau, and controls the uplift of Longshou Shan.Due to its lower closure temperature, the lower-temperature thermochronology method can more accurately constrain the cooling process of a geological body in the upper crust. In recent years, the low-temperature thermochronology method has been used more and more in the study of the erosion of orogenic belts, the evolution of sedimentary basins and tectonic geomorphology. In this study, the apatite (U-Th)/He(AHe) method is used to analyze the erosion and uplift of rocks on the south and north sides of Longshou Shan. 11 AHe samples collected from the south slope exhibit variable AHe ages between~8Ma and~200Ma, the age-elevation plot shows that before 13~17Ma, the erosion rate of the Longshou Shan is very low, and then rapid erosion occurs in the mountain range, which indicates that the strong uplift of Longshou Shan occurred at 13~17Ma BP, resulting in rapid cooling of the southern rocks. In contrast, 3 AHe ages obtained from the north slope are older and more concentrated ranging from 220Ma BP to 240Ma BP, indicating that the north slope can be seen as a paleo-isothermal surface and the activity of the north side is weak. The results of thermal history inverse modeling show that the South Longshou Shan Fault was in a tectonic quiet period until the cooling rate suddenly increased to 3.33℃/Ma at 14Ma BP, indicating that Longshou Shan had not experienced large tectonic events before~14Ma BP.
We believe that under the control of South Longshou Shan Fault, the mountain is characterized by a northward tilting uplift at Mid-Miocene. Our results on the initial deformation of the Longshou Shan, in combination with many published studies across the northeastern margin of the Tibetan plateau, suggest that the compression strain of the northeastern margin of the Tibetan plateau may expand from south to north, and the Tibetan plateau has expanded northeastward to the southern margin of the Alxa block as early as Mid-Miocene, making Longshou Shan the current structural and geomorphic boundary of the northeastern plateau. 相似文献
We believe that under the control of South Longshou Shan Fault, the mountain is characterized by a northward tilting uplift at Mid-Miocene. Our results on the initial deformation of the Longshou Shan, in combination with many published studies across the northeastern margin of the Tibetan plateau, suggest that the compression strain of the northeastern margin of the Tibetan plateau may expand from south to north, and the Tibetan plateau has expanded northeastward to the southern margin of the Alxa block as early as Mid-Miocene, making Longshou Shan the current structural and geomorphic boundary of the northeastern plateau. 相似文献
7.
Introduction Hexi Corridor, a corridor extended over 1 000 km and with a strike of WNW-ESE, is locatedbetween Alxa uplift and northern Qilianshan Caledonian folding belt of northern Qinghai-Xizang(Tibet) Plateau (Figure 1). In the paper, we will discuss the regions between Altun fault and Yu-mushan of the western Hexi Corridor, where the climate is arid, which results in sparse vegetation,but abundant oil and gas resource, and being one of the most important petroleum industry base… 相似文献
8.
基于地震剖面解释的构造分析表明，河西走廊西段及邻区发育有许多晚第三纪-第四纪的逆断层与走滑断层. 其主要类型有两种:一是与北祁连逆冲推覆作用有关的南倾逆断层，其走向北西，主要分布于北祁连山东北缘及河西走廊西南部地区；二是与阿尔金断裂活动有关的逆断层与走滑断层，主要分布于红柳峡、宽台山——合黎山地区. 这些断层与新生代始新世末期以来印-藏碰撞的远距离效应有关. 它们于晚第三纪开始活动，主要活动于第四纪时期，而且大多目前仍在活动，属于活动性断层，是河西走廊地区地震的潜发因素. 此外，它们还造成了地层的强烈变形，形成了一系列的地貌阶地和河流的水平错移. 相似文献
9.
通过室内航片判读和野外调查 ,在酒西盆地发现 3条全新世活动逆掩断层 ,它们全新世以来的垂直活动速率都很接近 ,为 0 18～ 0 2 5mm/a。通过探槽揭露出的 3条断层全新世以来各发生两次古地震事件。根据探槽揭露的古地震年代及断层活动所形成的微地貌特征分析 ,阴洼山断层是独立活动的 ;北大河断层和新民堡断层上的古地震事件在时间上可能非常接近 ,具有丛集特征 ,或者是一次地震事件分别破裂这两条断层 ,但目前的测年手段还无法区别它们是一次破裂事件形成还是时间上非常接近的两次事件所形成的 相似文献
10.
PRESENT KINEMATICS CHARACTERISTICS OF THE NORTHERN YUMUSHAN ACTIVE FAULT AND ITS RESPONSE TO THE NORTHEASTWARD GROWTH OF THE TIBETAN PLATEAU 下载免费PDF全文
下载免费PDF全文 CHEN Gan ZHENG Wen-jun WANG Xu-long ZHANG Pei-zhen XIONG Jian-guo YU Jin-xing LIU Xing-wang BI Hai-yun LIU Jin-rui AI Ming 《地震地质》2017,39(5):871-888
Qilian Shan and Hexi Corridor, located in the north of Tibetan plateau, are the margin of Tibetan plateau's tectonic deformation and pushing. Its internal deformations and activities can greatly conserve the extension process and characteristics of the Plateau. The research of Qilian Shan and Hexi Corridor consequentially plays a significant role in understanding tectonic deformation mechanism of Tibetan plateau. The northern Yumushan Fault, located in the middle of the northern Qilian Shan thrust belt, is a significant component of Qilian Shan thrust belt which divides Yumushan and intramontane basins in Hexi Corridor. Carrying out the research of Yumushan Fault will help explain the kinematics characteristics of the northern Yumushan active fault and its response to the northeastward growth of the Tibetan plateau.Because of limited technology conditions of the time, different research emphases and some other reasons, previous research results differ dramatically. This paper summarizes the last 20 years researches from the perspectives of fault slip rates, paleao-earthquake characteristics and tectonic deformation. Using aerial-photo morphological analysis, field investigation, optical simulated luminescence(OSL)dating of alluvial surfaces and topographic profiles, we calculate the vertical slip rate and strike-slip rate at the typical site in the northern Yumushan Fault, which is(0.55±0.15)mm/a and(0.95±0.11), respectively. On the controversial problems, namely "the Luotuo(Camel)city scarp" and the 180 A.D. Biaoshi earthquake, we use aerial-photo analysis, particular field investigation and typical profile dating. We concluded that "Luotuo city scarp" is the ruin of ancient diversion works rather than the fault scarp of the 180 A.D. Biaoshi earthquake. Combining the topographic profiles of the mountain range with fault characteristics, we believe Yumu Shan is a part of Qilian Shan. The uplift of Yumu Shan is the result of Qilian Shan and Yumu Shan itself pushing northwards. Topographic profile along the crest of the Yumu Shan illustrates the decrease from its center to the tips, which is similar to the vertical slip rates and the height of fault scarp. These show that Yumu Shan is controlled by fault extension and grows laterally and vertically. At present, fault activities are still concentrated near the north foot of Yumu Shan, and the mountain ranges continue to rise since late Cenozoic. 相似文献
11.
本文依据现今区域水准测量资料及跨断层位移测量资料阐明祁连山北缘断裂带现今活动特点是以近南北—北东向的挤压并兼有右旋走滑的水平活动方式为主,在玉门一张掖段并伴有近似反对称的升降运动,最大垂直形变梯度R为0.2毫米/公里·年左右,跨断层基线测量的缩短速率为0.2—0.5毫米/年。在河西走廊内部,受次级构造运动的影响也存在有局部的隆起、拗陷的升降运动及断裂活动 相似文献
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利用区域尺度双差层析成像方法,使用2009年1月至2017年2月的近震资料,对青藏高原东北缘及其邻区内记录到的地震事件进行震源位置和三维速度结构的联合反演.重新定位后震源空间位置得到明显改善,浅层的地震波速与地形和沉积层厚度对应较好,研究区地震主要发生在河西走廊过渡带的低泊松比区域.本文将研究区分为五个区域并分别对其层析成像结果进行了讨论,结果显示研究区不同地块之间地壳结构变化明显,地壳物质整体呈酸性,青藏高原东北缘地壳增厚可能主要发生在中下地壳. 相似文献
13.
酒西盆地为河西走廊西段的一个压陷性盆地,其内发育了多条晚第四纪活动逆断裂、褶皱带,是未来具有发生破坏性地震的潜在震源区.通过对酒西盆地和邻近地区9个潜在震源区的长期地震活动水平的对比研究,发现不同震级档的潜在震源区基本处于各自的一个地震活动水平档上.据此将玉门潜在震源区地震活动水平与其它潜在震源区对比,并结合区内活动构造及历史地震等活动特征,判定其震级上限为MS7.0.指出地震活动水平对比方法可作为潜在震源区划分中的一个辅助手段. 相似文献
14.
Sedimentary deposits in the foreland basin of the northeastern Qilian Mountains are crucial documents recording tectonic activity and climate changes on the Tibetan Plateau. In this study, luminescence dating was used to date alluvial conglomerates and fluvial terrace sediments collected from the Beida River in the Jiuquan Basin, a foreland basin in the Hexi Corridor, northeastern Qilian Mountains. Detailed sedimentology and luminescence ages reveal that alluvial conglomerates accumulated from before 620 ka to 12 ka and that sediment accumulation rates increased at ∼330 ka and ∼35 ka, coinciding with the dates of two tectonic events (∼350 and ∼50 ka) and followed by climate cooling (from marine isotope stage (MIS) 9 to MIS 8 and from MIS 3 to MIS 2). This reveals that variations in the sediment accumulation rates are controlled by the coupling of tectonic uplift and climate cooling. The highest terrace (T7) that developed on the alluvial conglomerate base formed at ∼ 12 ka. The incision rate in the early Holocene was ∼2.1 mm/yr and increased to ∼14.6 mm/yr during the middle and late Holocene. The variations in the river incision rate provide geomorphic evidence for Holocene climate patterns in arid and semiarid areas. Luminescence dating offers a credible temporal framework for the deposits and reveals climate and tectonic effects on the evolution of the foreland basin, northeastern Qilian Mountains. 相似文献
15.
A PRELIMINARY RESEARCH ON THE RIGHT-LATERAL STRIKE-SLIP CHARACTERISTICS AND THE STRUCTURAL SIGNIFICANCE OF THE NORTHERN KUANTANSHAN FAULTS,HEXI CORRIDER,BASED ON HIGH-RESOLUTION IMAGERY 下载免费PDF全文
下载免费PDF全文 The sinistral strike-slip characteristic of the Altyn Tagh Fault gradually disappears near the Jiuxi Basin at the west end of Hexi Corridor, and the Kuantanshan Fault and the northern marginal fault of Heishan on its east are thrust structures. There are two faults distributed in the north of Kuantanshan, namely, the Taerwan-Chijiaciwo Fault and the Ganxiashan Fault, both are featured with obvious activity. Predecessors thought that the Taerwan-Chijiaciwo Fault is a thrust fault with low movement rate, but there is few detailed study on its horizontal motion. Is there horizontal strike-slip movement in the northern marginal fault of Kuantanshan? This issue has an important significance to further explore the structural transformation mode between the Altyn Tagh strike-slip faults and the northern thrust faults in the north margin of Qilianshan. Using high resolution remote sensing images and field work, such as combining with UAV SfM photogrammetry, the paper studies the strike-slip characteristics of the Taerwan-Chijiaciwo Fault and Ganxiashan Fault on the northern margin of Kuantanshan, and get two preliminary understandings:(1) The northern marginal fault of Kuantanshan is an active right-lateral strike-slip fault with thrust component, the horizontal to vertical dislocation ratio is about 3-4 times. Based on the statistics of dislocation amount of the gullies and terraces along the north marginal Kuantanshan fault, it is preliminarily estimated that the late Pleistocene right-lateral strike-slip rate is about 0.2-0.25 mm/a and the Holocene right-lateral strike-slip rate is about 0.5-1.5 mm/a. (2) The main driving force to the tectonics at the western end of Hexi Corridor, where the northern marginal fault of Kuantanshan locates, comes from the northward extrusion of the Qilian Mountains, which results in the right-lateral strike-slip of the northern marginal fault of Kuananshan and the thrust movement of several faults inside the Jiuxi Basin. The effect of the Altyn Tagh Fault on other tectonic structures is not obvious in this region. 相似文献
16.
祁连山山间盆地内的新生代沉积物是研究新生代以来祁连山构造演化的重要材料.本文以位于祁连山中部祁连盆地内的新生代沉积物为研究对象,利用磁性地层学方法结合碎屑颗粒裂变径迹定年方法获取其沉积时代框架,在此基础上,结合岩性变化与沉积环境变迁分析祁连山构造演化历史.野外实测剖面显示该盆地内的第三系可划分为下部砾岩组和上部砂岩组两大岩性单元.古地磁结果显示砾岩组的沉积时代约为10—14.3Ma.砾岩组沉积大约在14.3 Ma开始形成,指示祁连山14.3 Ma以来构造活动变强烈.磁组构结果显示砾石组顶部沉积形成时的受力方向与现今祁连盆地周缘断层分布所指示的应力方向一致,表明这些断层大约在10 Ma附近开始活动.我们的结果揭示祁连山中部山脉14.3 Ma以来尤其在10 Ma附近构造活动较强烈.这与过去低温热年代学所获得的祁连山山体的快速冷却年龄及祁连山两端大型盆地内的第三系所记录的构造事件发生的时间基本吻合.而砂岩组的古地磁结果并未通过褶皱检验,其古地磁记录发生了后期重磁化,无法获得地层的准确沉积年龄. 相似文献
17.
L&#; Houyuan Wang Sumin Wu Naiqin Tong Guobang Yang Xiangdong Sheng Caiming Li Shijie Zhu Liping Wang Luo 《中国科学:地球科学(英文版)》2001,44(1):292-300
A new pollen record from the lake of Co Ngoin in the central Tibetan Plateau provides information on the vegetation and climate changes during the last 2.8 Ma. Seven major significant changes in pollen associations indicate the processes of vegetation change and possible tectonic uplifts. The seven changes in vegetation succession include a temperate montane conifer and broad-leaved mixed forest, cold temperate montane dark conifer forest, alpine shrub-meadow and alpine desert, montane dark coniferous forest and alpine shrub meadow, montane dark coniferous forest and alpine shrub meadow, montane dark coniferous forest and alpine meadow, and alpine desert and meadow. The pollen record provides the evidence of at least five times tectonic uplifts occurring at about 2.58 Ma, 1.87 Ma, 1.17 Ma, 0.83 Ma, and 0.3 Ma ago, respectively. Before 0.8 Ma, this region maintained the altitude below 4000 m a.s.l. Larger amplitude of uplift occurring at about 0.8 Ma ago enforced the plateau rising into cryosphere, shaping the basic topographic pattern of modern plateau. The major successions in vegetation of this area were largely controlled by stepwise uplift of the Tibetan Plateau.
相似文献18.
嘉峪关气氡映震情况讨论及玉门地震前水氡(嘉峪关,酒泉)异常特征 总被引：7，自引：2，他引：5
分析了1990年以来在祁连山断裂带上发生的7次地震前,嘉峪关气氡观测点和酒泉水氡的变化情况,发现在1990年10月20日天祝6．2级地震、1992年1月12日嘉峪关5．4级地震、1995年7月22日永登5．8级地震和2002年12月14日玉门5．9级地震前,嘉峪关气氡观测点均记录到短期的破年变异常,而酒泉水氡在玉门地震前为明显的突变型中期异常。 相似文献
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阴洼山断裂属于河西走廊内的断裂带,位于嘉峪关以西28km的阴洼山北侧及附近,呈NW向延伸,长25km,自NW向SE具有活动时代逐渐变新的特点。其西北段仅切错了白垩系和上新统,中段则切错到上更新统(被断最新坡积物22.4kaBP,覆盖坡积物8.6kaBP),而东南段切错了全新统(断层楔堆积物4.8～5.1kaBP)。断裂的活动性质在剖面上表现为西南盘上升、东北盘下降的相对位移,而平面上为右行的走滑。该断裂在晚更新世末(10～11kaBP左右)和全新世中期(5kaBP左右)发生过2次明显的新活动 相似文献