共查询到19条相似文献，搜索用时 203 毫秒
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在大比例尺遥感影像解译的基础上,利用野外调查测量、探槽开挖及热释光测年的方法,对那拉提断裂进行了研究。那拉提断裂是一条晚第四纪以来仍有较强的活动大型逆冲左旋走滑断裂带,断裂带宽度巨大,由多条倾向不同的次级断裂组成,分布在南北宽数千米的范围内。断裂断错了那拉提山前晚第四纪以来的各级地貌面,主要表现为断层陡坎、冲沟水系和地貌面的左旋位移,根据实测陡坎高度及对应地貌面的定年,获得断裂所造成的南北向地壳缩短速率在0.7～1.0 mm/a左右,这表明天山内部同样存在明显的构造变形。 相似文献
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阿尔金活动断裂带东段的滑动速率由西向东逐渐减小,而肃北是阿尔金断裂东段滑动速率的"突变点"之一。在肃北以东分布多条分支断裂,野马河北侧断裂便是其中的一条。野马河北侧断裂长约30km,总体走向NEE,该断裂沿野马河盆地北侧山前洪积扇延伸,沿断裂具有大量的左旋走滑和逆冲等地貌现象,多处冲沟出露有断层剖面。野外调查结果表明该断裂是一条左旋走滑兼逆冲断裂,错断了晚更新世时期形成的洪积扇或冲沟阶地。通过实测得到地貌面左旋、垂直错动数据,并采集样品测试相关地貌面的年龄,估算该断裂晚更新世以来的平均水平滑动速率为(1.27±0.18)mm/a,平均逆冲速率为(0.4±0.07)mm/a,该断裂分解了阿尔金断裂东段的部分运动量 相似文献
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通过对福建东南沿海海拔50m以下几个地貌面的时代确定,研究了长乐-诏安NE向断裂带和与之相交切的NW向断裂带第四纪以来的活动性。结果表明:区内50m以下几个地貌面分为侵蚀-剥蚀阶地和堆积阶地,属晚更新世以来几个时期所形成;断裂在切割某个地貌面时,其地貌面的形成年代可确定为该断裂的活动年代;长乐-诏安NE向断裂带中的平潭青峰-东山澳角断裂的有些地段为晚更新世晚期(Q3p)活动断裂,垂直滑动速率为1.1～2.2mm/a;长乐-东山前梧断裂主要活动时代在中更新世(Q2p);九龙江下游NW向断裂带中的江东桥(北溪)-海沧断裂,其NW段江东桥(北溪)断裂为早第四纪(Q1p-2)断裂,SE段海沧-钱屿断裂为晚更新世(Qp3)活动断裂 相似文献
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根据研究区的构造地貌特征，断裂两盘第四系和等时地貌面的对比以及其它宏观和微观的断裂构造迹象，讨论了四会－吴川断裂南段晚更新世以来的活动性，得出该时段，该断裂在该地区相对稳定的基本认识。 相似文献
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深圳市观澜断裂第四纪活动性研究 总被引：2，自引：1，他引：1
观澜断裂是深圳陆域地区规模最大的北北西向断裂。通过地质地貌调查、联合钻孔探测及地质年代测定等技术方法对观澜断裂的第四纪活动性进行了详细考察与综合研究。结果表明：穿越低丘陵台地地貌区的观澜断裂两侧未见地貌差异或现代构造形变现象;4个典型地质露头和2条钻孔联合剖面显示断裂没有扰动上覆第四系．观澜大布巷钻孔探测剖面还获得了断裂上覆冲洪积砂层底部12．6±2．4Ka的光释光测年数据;断裂物质主要由碎裂岩、构造角砾岩、硅化岩等组成．可见硅质被膜及半固结岩屑或岩粉状物质;7个断层样品的电子自旋共振测试结果显示断裂的最新活动年龄为距今21．1±2．1万年。结合12条浅层地震测线探测未发现断裂错移第四纪覆盖层底界的事实．得出了观澜断裂最新一次活动发生在中更新世晚期．自晚更新世中期以后没有新的近地表活动的结论。 相似文献
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TERRACE DEFORMATION AND SLIP RATES OF THE DONGBIELIEKE FAULT IN WESTERN JUNGGAR BASIN SINCE THE LATE QUATERNARY 
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下载免费PDF全文 Strike-slip fault plays an important role in the process of tectonic deformation since Cenozoic in Asia. The role of strike-slip fault in the process of mountain building and continental deformation has always been an important issue of universal concern to the earth science community. Junggar Basin is located in the hinterland of Central Asia, bordering on the north the Altay region and the Baikal rift system, which are prone to devastating earthquakes, the Tianshan orogenic belt and the Tibet Plateau on the south, and the rigid blocks, such as Erdos, the South China, the North China Plain and Amur, on the east. Affected by the effect of the Indian-Eurasian collision on the south of the basin and at the same time, driven by the southward push of the Mongolian-Siberian plate, the active structures in the periphery of the basin show a relatively strong activity. The main deformation patterns are represented by the large-scale NNW-trending right-lateral strike-slip faults dominated by right-lateral shearing, the NNE-trending left-lateral strike-slip faults dominated by left-lateral shearing, and the thrust-nappe structure systems distributed in piedmont of Tianshan in the south of the basin. There are three near-parallel-distributed left-lateral strike-slip faults in the west edge of the basin, from the east to the west, they are:the Daerbute Fault, the Toli Fault and the Dongbielieke Fault. This paper focuses on the Dongbielieke Fault in the western Junggar region. The Dongbielieke Fault is a Holocene active fault, located at the key position of the western Junggar orogenic belt. The total length of the fault is 120km, striking NE. Since the late Quaternary, the continuous activity of the Dongbielieke Fault has caused obvious left-lateral displacement at all geomorphologic units along the fault, and a linear continuous straight steep scarp was formed on the eastern side of the Tacheng Basin. According to the strike and the movement of fault, the fault can be divided into three segments, namely, the north, middle and south segment.
In order to obtain a more accurate magnitude of the left-lateral strike-slip displacement and the accumulative left-lateral strike-slip displacement of different geomorphic surfaces, we chose the Ahebiedou River in the southern segment and used the UAV to take three-dimensional photographs to obtain the digital elevation model(the accuracy is 10cm). And on this basis, the amount of left-lateral strike-slip displacement of various geological masses and geomorphic surfaces(lines)since their formation is obtained. The maximum left-lateral displacement of the terrace T5 is(30.7±2.1)m and the minimum left-lateral displacement is(20.1±1.3)m; the left-lateral displacement of the terrace T4 is(12±0.9)m, and the left-lateral displacement of the terrace T2 is(8.7±0.6)m. OSL dating samples from the surface of different level terraces(T5, T4, T2 and T1)are collected, processed and measured, and the ages of the terraces of various levels are obtained. By measuring the amount of left-lateral displacements since the Late Quaternary of the Dongbielieke Fault and combining the dating results of the various geomorphic surfaces, the displacements and slip rates of the fault on each level of the terraces since the formation of the T5 terrace are calculated. Using the maximum displacement of(30.7±2.1)m of the T5 terrace and the age of the geomorphic surface on the west bank of the river, we obtained the slip rate of(0.7±0.11)mm/a; similarly, using the minimum displacement of(20.1±1.3)m and the age of the geomorphic surface of the east bank, we obtained the slip rate of(0.46±0.07)mm/a. T5 terrace is developed on both banks of the river and on both walls of the fault. After the terraces are offset by faulting, the terraces on foot wall in the left bank of the river are far away from the river, and the erosion basically stops. After that, the river mainly cuts the terraces on the east bank. Therefore, the west bank retains a more accurate displacement of the geomorphic surface(Gold et al., 2009), so the left-lateral slip rate of the T5 terrace is taken as(0.7±0.11)mm/a. The left-lateral slip rate calculated for T4 and T2 terraces is similar, with an average value of(0.91±0.18)mm/a. In the evolution process of river terraces, the lateral erosion of high-level terrace is much larger than that of low-level terrace, so the slip rate of T4 and T2 terraces is closer to the true value. The left-lateral slip rate of the Dongbielieke Fault since the late Quaternary is(0.91±0.18)m/a. Compared with the GPS slip rate in the western Junggar area, it is considered that the NE-trending strike-slip motion in this area is dominated by the Dongbielieke Fault, which absorbs a large amount of residual deformation while maintaining a relatively high left-lateral slip rate. 相似文献
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The Riyue Mt. Fault is a secondary fault controlled by the major regional boundary faults (East Kunlun Fault and Qilian-Haiyuan Fault). It lies in the interior of Qaidam-Qilianshan block and between the major regional boundary faults. The Riyue Mt. fault zone locates in the special tectonic setting which can provide some evidences for recent activity of outward extension of NE Tibetan plateau, so it is of significance to determine the activity of Riyue Mt. Fault since late Pleistocene to Holocene. In this paper, we have obtained some findings along the Dezhou segment of Riyue Mt. Fault by interpreting the piedmont alluvial fans, measuring fault scarps, and excavating trenches across the fault scarp. The findings are as follows:(1) Since the late Pleistocene, there are an alluvial fan fp and three river terraces T1-T3 formed on the Dezhou segment. The abandonment age of fp is approximately (21.2±0.6) ka, and that of the river terrace T2 is (12.4±0.11) ka. (2) Since the late Pleistocene, the dextral strike-slip rate of the Riyue Mt. Fault is (2.41±0.25) mm/a. In the Holocene, the dextral strike-slip rate of the fault is (2.18±0.40) mm/a, and its vertical displacement rate is (0.24±0.16) mm/a. This result indicates that the dextral strike-slip rate of the Riyue Mt. Fault has not changed since the late Pleistocene. It is believed that, as one of the dextral strikeslip faults, sandwiched between the the regional big left-lateral strike-slip faults, the Riyue Mt. Fault didn't cut the boundary zone of the large block. What's more, the dextral strike-slip faults play an important role in the coordination of deformation between the sub-blocks during the long term growth and expansion of the northeast Tibetan plateau. 相似文献
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INFLUENCE OF TECTONICS AND CLIMATE ON THE EVOLU-TION OF FLUVIAL TERRACES: A CASE STUDY OF THE HONGSHUIBA AND MAYING RIVERS IN THE NORTHERN MARGIN OF THE QILIAN MOUNTAINS 下载免费PDF全文
下载免费PDF全文 TIAN Qing-ying ZHENG Wen-jun ZHANG Dong-li ZHANG Yi-peng XU Bin-bin HUANG Liu-ting 《地震地质》2017,39(6):1283-1296
In tectonically active regions, geomorphic features such as fluvial terraces can be interpreted as the consequence of tectonic and climatic forcing. However, deciphering and distinguishing tectonic impacts and climate changes remain a challenge. In this study, we examine the terraces along the Hongshuiba river and Maying river, which flow across the Fudongmiao-Hongyazi fault in the northern margin of the Qilian Mountains. Our purpose is to analyze the relative roles of tectonics and climate in shaping orogenic topography in this area. 8~9 levels of river terraces were identified through field observations, interpretation of satellite images and using DEMs. According to relative heights and ages of T5 of the Hongshuiba river and T6 of the Maying river, the incision rates are calculated to be (10.2±2.0)mm/a and (12.2±2.8)mm/a, respectively. Furthermore, the thrust rate along the Fodongmiao-hongyazi fault was determined based on offset terraces and OSL dating, which are ten times less than river incision rates approximately. Comparing the uplift rate and incision rate in the northern margin of the Qilian Mountains and adjacent areas, we inferred that climate change is the most plausible controlling factor in the evolution of the river terraces, while tectonics plays a minor role in this process. 相似文献
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ANALYSIS OF THE LATE QUATERNARY ACTIVITY ALONG THE WENCHUAN-MAOXIAN FAULT -MIDDLE OF THE BACK-RANGE FAULT AT THE LONGMENSHAN FAULT ZONE 下载免费PDF全文
下载免费PDF全文 The Longmenshan fault zone is located in eastern margin of Tibetan plateau and bounded on the east by Sichuan Basin, and tectonically the location is very important. It has a deep impact on the topography, geomorphology, geological structure and seismicity of southwestern China. It is primarily composed of multiple parallel thrust faults, namely, from northwest to southeast, the back-range, the central, the front-range and the piedmont hidden faults, respectively. The MS8.0 Wenchuan earthquake of 12th May 2008 ruptured the central and the front-range faults. But the earthquake didn't rupture the back-range fault. This shows that these two faults are both active in Holocene. But until now, we don't know exactly the activity of the back-range fault. The back-range fault consists of the Pingwu-Qingchuan Fault, the Wenchuan-Maoxian Fault and the Gengda-Longdong Fault. Through satellite image(Google Earth)interpretation, combining with field investigation, we preliminarily found out that five steps of alluvial platforms or terraces have been developed in Minjiang region along the Wenchuan-Maoxian Fault. T1 and T2 terraces are more continuous than T3, T4 and T5 terraces. Combining with the previous work, we discuss the formation ages of the terraces and conclude, analyze and summarize the existing researches about the terraces of Minjiang River. We constrain the ages of T1, T2, T3, T4 and T5 surfaces to 3~10ka BP,~20ka BP, 40~50ka BP, 60ka BP and 80ka BP, respectively. Combining with geomorphologic structural interpretation, measurements of the cross sections of the terraces by differential GPS and detailed site visits including terraces, gullies and other geologic landforms along the fault, we have reason to consider that the Wenchuan-Maoxian Fault was active between the formation age of T3 and T2 terrace, but inactive since T2 terrace formed. Its latest active period should be the middle and late time of late Pleistocene, and there is no activity since the Holocene. Combining with the knowledge that the central and the front-range faults are both Quaternary active faults, the activity of Longmenshan fault zone should have shifted to the central and the front-range faults which are closer to the basin, this indicates that the Longmenshan thrust belt fits the "Piggyback Type" to some extent. 相似文献
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THE LATE QUATERNARY TECTONIC DEFORMATION REVEALED BY THE TERRACES ON THE BAIYANG RIVER IN THE NORTHERN QILIAN MOUNTAINS 下载免费PDF全文
下载免费PDF全文 The Qilian Mountains, as a major orogenic belt in the northeastern margin of the Tibetan plateau, is the forefront of the expansion of the plateau to the northeast, where thrusts and folds dominate tectonic deformation. The Baiyang River starts from the inner Qilian Mountains, flowing northward across various structures, and finally into the Jiuxi Basin. This work focused on exhaustive investigations to the terraces on this river to characterize the Late Quaternary tectonic deformation in this region. The results show that (1)these river terraces on the Baiyang River are segmented, of which multiple levels developed at steep terrains and anticlines in the basin. Bounded by the Niutou Mountains, mainly 2-3 and 4-5 levels of terraces formed in the upper and lower reaches, respectively. (2)The longitudinal profiles along the river suggest a vertical motion rate of the Changma fault as (0.32±0.09)mm/a and crustal shortening rate (0.12±0.09)mm/a. There was no vertical activity since the formation of T5 surface (13ka)on the Hanxia-Dahuanggou fault. At the terrace T5 (9ka)on the Laojunmiao anticline, fold uplift amounts (6.55±0.5)m and shortening amounts (3.47±0.5)m, yielding uplift and shortening rates (1.23±0.81)mm/a and (0.67±0.44)mm/a, respectively. The Baiyang River anticline began to be active about 300ka with uplift and shortening rates (0.21±0.02)mm/a and (0.14±0.03)mm/a, respectively since 170ka. (3)In the Qilian Mountains, there were two different deformation characteristics in response to the expansion of the Tibetan plateau. Shear deformation dominates the inner Qilian Mountains, which is manifested as lateral extrusion of blocks. In the northern margin of Qilian Mountains and Jiuxi Basin, the deformation is dominated by compression, expressing crustal shortening and uplift, and the shortening within the basin accounts about half of the total deformation. 相似文献
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秦岭北麓晚第四纪断层陡坎的初步研究 总被引：4，自引：1，他引：4
根据航片解译和野外调查,发现在秦岭北麓第四纪松散沉积物中发育有断层陡坎,本文依据对这些陡坎的地质地貌分析、地形剖面测制、探槽揭露及测年数据,讨论了断层陡坎的空间分布和形态学特征、生成时代和断距,评估了秦岭北麓断裂在晚第四纪的活动强度。由断层陡坎高度经过校核获得断距变化范围在1.1至7.9米之间,由此求得秦岭北麓断裂中段全新世中晚期以来平均滑动速率接近1mm/a,西段在眉县一带为0.5mm/a左右。晚更新世以来,发生过3—4次古地震事件 相似文献
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Located at the west of the Linfen basin, the Luoyunshan piedmont fault zone controls the western boundary of the basin. According to the measurements of the terraces in eight gullies along the Luoyunshan fault zone, five levels of terraces, namely T1～T5 have developed in these gullies. The heights of terraces T1, T2, T3, T4 and T5 are about 3m, 8～10m, about 20m, about 30m and 40～50m, respectively. The dating data of the terraces and investigation of the faulted landforms show that the Luoyunshan fault zone has experienced much activity since the Late Quaternary. The uplift rate of the terraces was 0.41mm/a since the Middle-Late Pleistocene, and 0.75mm/a since the Holocene. The increasing trend of uplift rate of the terraces along the Luoyunshan fault zone from the Middle-Late Pleistocene to Holocene indicates the tendency of gradual tectonic uplift of the fault zone since the late Quaternary. This is in good agreement with the increasing trend of subsidence rate of the Linfen basin from the Late Pleistocene to Holocene. 相似文献