共查询到19条相似文献，搜索用时 359 毫秒
1.
临潼-长安活动断裂带是渭河盆地内部西安凹陷与骊山凸起之间一条重要的活动断裂带,由2条次级断层组成,以灞河、皂河为界划分为北东、中、南西3段,前人对晚更新世以来的断裂的活动性存在2种不同的认识。为了确定临潼-长安断裂带晚更新世以来的活动性,文中以黄土S1、L1S和S0为确定垂直位移的标志和年代标尺,通过DEM地貌分析、断层露头调查,结合地壳形变资料,分析得出临潼-长安断裂带北东段晚更新世以来断裂活动性强,中段活动性其次,南西段活动性弱,与DEM显示的现今临潼-长安活动断裂带上下盘的地貌差异有很好的吻合性。 相似文献
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根据渗水实验、孔隙度、粒度、磁化率测定,研究了长武黄土剖面L3～S6土层的渗透性及其成因。研究结果表明,L3,L4,L5和L6黄土层渗透性较强,稳定入渗速率较高,它们的渗透系数变化在0.57～1.06mm/分之间,4层平均为0.75mm/分;S3,S4,S5和 S6古土壤渗透性较弱,稳定入渗率较低,它们的渗透系数变化在0.18～0.71mm/分之间,4层平均为0.44mm/分。红色古土壤达到稳定入渗率的时间一般比黄土层要长; 黄土层的平均空隙度比红褐色古土壤高,渗透性强,粒度成分较粗,黄土层比红褐色古土壤层更利于构成含水层; 红褐色古土壤层粒度成分细,空隙度低,渗透性弱,比黄土层利于形成隔水层。长武第4层古土壤厚度小,纵向裂隙发育强,入渗速率较大,不易形成隔水层。磁化率、粘粒含量资料表明红褐色古土壤层与黄土层渗透性、含水空间和隔水性的差异主要是当时气候冷干和温湿交替变化的结果。 相似文献
3.
山西平陆黄底沟入三门峡水库北侧发育了一级湖滨阶地(T3)和两级河流阶地(T2和T1)。阶地上覆黄土地层野外划分和室内磁化率测试结果与蓝田段家坡黄土地层的对比结果表明,T3上覆黄土地层最底部为古土壤层S2;T2最底部为黄土层L2中弱发育古土壤层L2-2;T1最底部为马兰黄土L1中弱发育古土壤层L1-4。根据黄土-古土壤年代序列及光释光(OSL)年龄测试结果,T3,T2和T1阶地分别于245kaB.P. ,149kaB.P.和50kaB.P. 前形成。其中,T3和T2阶地的形成时间,分别代表了山西平陆古三门湖开始消亡和最老黄河阶地形成的年代。古三门湖消亡与黄河贯通三门峡的时代是否一致,有待进一步研究。 相似文献
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通过对洛川凤栖镇L12～S15土层8个层位16个实验点的入渗实验,研究了离石黄土下部层位的入渗特征。结果表明,洛川凤栖镇离石黄土下部层位黄土层的渗透系数较大,L12,L13,L14和L15这4个层位的平均值为0.90mm/分; 古土壤层的渗透系数较小,S12,S13,S14和S15的4个层位的平均值为0.35mm/分。L12,L13和L15黄土层含水空间发育较好,利于构成含水层; S12,S13,S14和S15古土壤层含水空间发育弱,利于构成隔水层。上覆总厚70余米的土层重力作用没有改变洛川离石黄土下部黄土层作为含水层和红色古土壤作为隔水层的基本特性,它们的水理性质仍是受沉积时的气候条件和成壤作用的强弱控制。古土壤层也具有一定的渗透性,这是黄土地下水常常具有多层性的原因,也是造成黄土地下水分散、含水层富水量少的主要原因。离石黄土下部黄土层含水空间发育好和利于构成含水层主要是当时冷干的气候决定的,红色古土壤含水空间发育弱和利于构成隔水层主要是当时温湿的气候决定的。将洛川黄土渗水实验数据用3种入渗公式分别进行拟合得出,常用的通用经验公式和考斯加科夫公式基本适用于描述洛川凤栖镇离石黄土下部层位的入渗规律,通过计算获得的2个经验公式各参数的均值和标准差为水文和农业部门应用黄土入渗经验公式提供了重要参考值。研究还揭示,第四纪环境变化理论研究在黄土水资源开发利用方面有重要应用价值。可以根据黄土与古土壤的成壤强弱判别地下水富集规律和富集层位。成壤强、隔水性好的古土壤层和其上的成壤作用很弱、含水空间发育好的黄土层是很好的地下水含水组合,最利于地下水的富集; 成壤作用弱、隔水性差的古土壤和其上厚度小、受风化成壤作用相对较强的黄土层是较差的含水组合,不利于地下水的富集。 相似文献
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文章基于15个剖面,采用土壤学使用的风化成壤强度指数(游离铁FeD/全铁FeT),对黄土高原S0,L1,S1,S4,S5-1层位的风化成壤强度的空间变化进行研究,并与磁化率反映的特征进行对比。结果表明,冰期(黄土层)和间冰期(古土壤层)的风化成壤强度均呈现由东南向西北减弱的特征,与现代季风气候的基本格局一致。然而,冰期时(以L1为代表)整个黄土高原南北气候梯度很弱,间冰期南北气候梯度远大于冰期,反映了冰期时夏季风环流对黄土高原影响很小,南北气候梯度更多体现了气候带的纬度效应。结果同时表明,间冰期时黄土高原地区风化成壤强度和南北气候梯度不具严格的对应关系。S1和S5-1指示了当时较强的夏季风环流,冬季风的影响相对亦较强,而S0和S4发育时期高原南北风化成壤强度的梯度明显减小,反映了当时黄土高原在夏季风影响的背景下,冬季风的影响亦减弱,导致南北梯度的减小。因此,黄土高原风化成壤强度的空间变化指示了冬、夏季风环流不同的消长关系,对研究高低纬度气候驱动力的相互作用具有重要意义。 相似文献
6.
2008年5月12日14时28分04秒,四川省汶川县发生MS8.0大地震。发震断裂为龙门山断裂带,地震地表破裂带分布在北川-映秀断裂上的映秀-石坎子段和江油-灌县断裂上的磁峰-睢水段。平武县平通镇地表破裂现象典型,在T1和T2阶地上形成了地震断坎和裂缝。应用高精度GPSRTK技术对平通镇地震断坎及两侧作详细的地形测量,并测量了线性显著的路面中线和鱼塘西边壁。在室内生成高分辨率DEM与大比例尺地形剖面图,量取同震垂直与水平位移,并估算压缩缩短量和断层产状。结果显示汶川8.0级地震在平通镇形成的同震垂直位移为3.0±0.1m,右旋水平位移为4.0±0.2m,压缩缩短量为2.5m,断层产状为NE40°/NW∠50°。平通镇的同震右旋位移与本次地震的最大右旋位移相近,而逆冲垂直位移有所降低。 相似文献
7.
高密度电法在和田隐伏断层探测中的应用 总被引：1，自引：0，他引：1
西昆仑山前一系列的新生代背斜的翼部往往伴生向南斜倾的逆断裂,这些断裂隐伏于早更新世或中更新世洪积砂砾石层,构成了和田隐伏断裂带。该断裂带由2条陡坎状断层组成,宽约10.6km,深度20~300m,落差110~270m。根据卫星影像和地质工作成果,和田隐伏断裂的一支从和田市南部穿过,但南郊飞机场附近没有露头,为探查断层在该区域的位置及深度,沿垂直于推测的断层走向布设2条测线,采用温纳（WN）测量系统对其进行探测。探测结果表明：2条测线皆发现了逆断层,均上切错断了上覆晚更新世地层,其中测线1存在2处断层,一处断层倾向南,倾角50°左右,另一处断层倾向北,倾角约55°;测线2存在一处断层,倾向北,倾角近80°。通过比对高密度电法资料和地质出露点剖面,推断和田断层在第四系以来有过两次明显的活动,导致晚更新世砂砾石土层被断错。 相似文献
8.
富蕴断裂带位于阿尔泰山南侧,横切阿尔泰山褶皱带南缘及额尔齐斯深断裂,是一条呈北北西向展布的右旋走滑断裂带。沿断裂带发育一系列错断水系、错断冲积扇、挤压脊、走滑拉分盆地等反映右旋走滑活动的典型构造地貌标志。本研究在高分辨率遥感图像和数字高程模型分析的基础上,结合野外实地构造地貌测量,对沿富蕴断裂带发育的系统错断水系特征进行了详细分析研究。研究结果表明,沿富蕴断裂带发育不同级别的错断水系,大致可划分为6级:1931年地震形成的冲沟;90m左右断距的错断水系;150m左右断距的错断水系;500m左右断距的错断水系;1500m左右断距的错断水系;2000m以上断距的错断水系。同时,结合研究区及邻区的第四纪冰川资料讨论了不同级别水系可能形成时间:恰尔沟三级支流可能形成时间为末次冰期Ⅲ阶段末期,约20ka;恰尔沟二级支流可能形成时间为末次冰期Ⅰ阶段末期,约120ka;恰尔沟一级支流可能形成于该地区冰川广泛消融的倒数第2次冰期的Ⅱ阶段末期,约为250ka;恰尔沟、水磨沟、白杨沟、乌铁布拉克河、卡布尔特河等可能形成于倒数第3次冰期Ⅱ阶段末期,约为360ka。最后,我们估算出富蕴断裂带晚第四纪以来的平均右旋走滑速率为1.46～4.99mm/a。 相似文献
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10.
临潼-长安断裂构造发育特征——基于人工地震探测结果分析 总被引：1，自引：0，他引：1
临潼-长安断裂地处黄土区,黄土稳定性差,以往多采用地面和遥感地质调查等方法加以研究。由于受黄土塬边滑坡或湿陷性影响,得到的断层剖面构造特征不但深度有限可靠性差,而且深部的构造特征仅具有推测性质。地震勘探是探测深部地质构造最有效的地球物理勘探方法之一。利用地震探测获得了深达千余m的地质剖面,并从区域构造研究入手,划分了临潼-长安断裂与周至-户县凹陷、骊山凸起的分界,确定了临潼-长安断裂的总体剖面构造特征。 相似文献
11.
M. L. Kopp 《Geotectonics》2011,45(5):394-410
The present-day denudation scarps on the Russian Plain, many hundred kilometers in extent, resemble faults. The kinematics
of low-amplitude displacements deduced from their configuration and mesotectonic measurements corresponds to the recent regional
stress regime transmitted in the lateral direction to the platform basement via consolidated crust from the zone of Alpine
collision. At the same time, no high-amplitude regional faults are known near the scarps. This paradox can be resolved assuming
that the scarps are formed by tightening of low-amplitude stress-release joints rather than along extended faults. The zones
of such joints mark the belts of stresses in the platform basement induced by collision. Since the erosion that forms a scarp
relaxes residual tectonic stresses, a river’s bank is not destroyed chaotically, so that particular segments of scarp follow
paths of the regional stress field. Thus, the configuration of banks, in combination with other structural features, makes
its possible to forecast the character of recent collision-related stresses transmitted from a depth. 相似文献
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岷江断裂带晚新生代逆冲推覆构造：来自钻孔的证据 总被引：6，自引：0，他引：6
岷江断裂带由2个不同性质的断裂组成:早期岷江逆冲断裂和晚期岷江正断裂。野外地质调查和钻孔资料发现在岷江西侧山麓之下存在一套厚度大于110m的早更新世灰黑色湖相地层,三叠系灰岩逆掩在这套湖相地层之上。由此确定岷江断裂是一条西倾的逆冲断层,逆冲作用发生在中更新世之前。在中更新世时期,岷江逆冲断裂发生构造负反转,在其前缘形成一条东倾的正断层,它控制了岷江上游漳腊盆地的发育。本文认为,岷山地区现今地震活动并非受控于岷江断裂带,而可能受到虎牙断裂及岷山隆起深部滑脱构造的控制,岷江断裂带位于该深部滑脱构造的上部。进而认为逆冲—推覆构造样式可能是青藏高原东缘晚新生代造山和快速隆升的主要变形机制。 相似文献
14.
The Aravalli Range runs southwest from Delhi for a distance of about 700 km. Its western margin is well defined, but the eastern margin is diffuse. Five geomorphic provinces are recognized in the study area: the western piedmont plains; the ridge and valley province which in the Central Aravallis occurs at two different heights separated by a fault scarp; the plateau province demarcated from the former by a fault scarp, confined to the Southern Aravallis, and occurring for a short stretch at two heights across another fault scarp; the BGC rolling plains east of the Range; and the BGC uplands south of the above. The scarps coincide with Precambrian faults. A series of rapids and water-falls, together with deeply entrenched river courses across the scarps and the youthful aspects of the escarpments with no projecting spurs, or straight river courses along their feet, all point unmistakably to a recent or post-Neogene vertical uplift along pre-existing faults. Presence of knickpoints at a constant distance from the Range in all west-flowing rivers, the ubiquitous terraces, and river courses entrenched within their own flood-plain deposits of thick gritty to conglomeratic sand, are indicative of a constant disturbance with a gradual rise of the Range east of the knickpoint, wherefrom the coarse materials were carried by the fast west-flowing streams. There is a differential uplift across the plateau scarp together with a right-lateral offset.This epeirogenic tectonism is ascribed to the collision of the Eurasian and the subducting Indian plates and to a locking of their continental crusts. By early Pleistocene, with the MBT gradually dying off, continued plate movement caused a flexural bending of the plate by a moment generated at the back, and a possible delinking of the continental crust along the zone of subduction. The felexural bending ripped open the Precambrian regional faults. The differential uplift and the difference in the distances of the nodes on two sides of the major reactivated fault were possibly caused by a difference in the values of the flexural rigidity and the foundation modulus owing to a slight compositional difference of the constiuent rocks in the two sectors. 相似文献
15.
Manal Shakir Al-Kubaisi 《Arabian Journal of Geosciences》2014,7(3):1001-1015
Distinctive landform of juxtaposition of relatively straight exposures of slope and Quaternary deposits against older rock units in addition to the omission of younger ones are recognized in the Zagros low-folded zone of Mosul area. This phenomenon is attributed to the kinetics and the geometry of basin inversion. Positively inverted faults and their associated folds developed up-growing structures with reverse fault scarps. Those growing structures are passively uplifted above lower blind thrust fault. The up-moving faults were subjected to erosion. The interaction between the rates of erosion and uplift controls the formation of slope and other Quaternary deposits and their distribution. Fast uplift of the reverse faults resulted into formation of cliffs representing the fault scarps and the formation of slope deposits directly next to them. The linear traces of the reverse faults control the straight linear map view distribution of the associated slope deposits. Slower rates of uplift give considerable time to erosion and in consequence the fault scarps are deeply eroded and disappear. This process also resulted into deposition of the other types of Quaternary deposits but still the linear contact between the geological rock units and the Quaternary deposits is existing and easily noticed. The analysis of these features and their interpretation has resulted in a new interpretation of the geological maps of Mosul area and the recognition of many reverse faults that bound the exposed structures. This fault system is used to restore the configuration of the original Late Cretaceous extensional basin. 相似文献
16.
花海断裂位于河西走廊西段花海盆地内,总体走向NNW-SSE,长约38 km,为一条隐伏断裂,研究其空间展布、运动性质和活动历史对于理解青藏高原北缘的构造变形和扩展方式有重要意义.基于卫片解译、野外实地和槽探,结合光释光测年和地球物理资料,发现沿双泉子、大泉至小泉一带,发育一段长约8 km的地形陡坎,代表断裂控制下褶皱作用的地形表现.沿陡坎走向向南,断裂一直隐伏延伸至宽滩山和黑山以北.现有资料分析表明,断裂经历了早白垩世的正断、晚白垩的逆冲运动.新生代以来,断裂继承了之前的逆冲运动并一直持续至全新世中晚期.高原北缘的侧向扩展,使得作为三危山与阿尔金断裂之间块体边界的三危山、干峡山、宽滩山和塔尔湾-登登山-池家刺窝断裂发生以左旋走滑为主兼有逆冲的变形,导致了边界断裂控制山体的隆升,而内部的块体受压剪作用向北东运动.花海断裂的逆冲运动即是该次构造活动事件的响应. 相似文献
17.
通过可控源音频大地电磁测深(CSAMT)、浅层地震和高密度电法地球物理探测手段建立的联合剖面对比,同时开展钻探工程及古地磁样品测试,对南口-孙河断裂带(北段)结构及活动性进行研究。南口-孙河断裂带(北段)由1条主断裂和1条次级断裂组成,断裂带宽约400m,表现为阶梯状断层,向上延伸至第四系。第四纪以来,断裂带活动显著,体现为松散层浅部引张的特点。根据断裂两盘第四纪以来各阶段累积垂直落差,计算出主断裂及次级断裂的活动速率。主断裂在早更新世、中更新世、晚更新世、全新世活动速率分别为0.161mm/a、0.072mm/a、0.468mm/a、0.52mm/a,次级断裂在早更新世、中更新世、晚更新世、全新世活动速率分别0.049mm/a、0.052mm/a、0.223mm/a、0.04mm/a。 相似文献
18.
柯坪断隆内断裂发育，笔者根据野外及地震数据对各主要断裂和二级断裂进行了分析，认为柯坪塔格断裂形成于晚第三纪，沙井子断裂早期与柯坪塔格具有不同的发育历史，阿合奇断裂形成于挤压而非走滑的背景下，皮羌断裂和印干走滑断裂其实是协调作用的捩断层。萨尔干断裂是一条假走滑断层，实际上应该是一条撕裂断层。在挤压背景下形成了二类主要的断裂构造组合样式；叠瓦推覆体、构造窗。笔者认为柯坪断隆上的构造其实是印度板块和欧亚板块远程碰撞造山和板内变形的一种表现。 相似文献
19.
Stephen J. Martel 《Engineering Geology》1989,27(1-4):489-507
The Fish Springs fault is a primary strand in the northern end of the Owens Valley fault zone (OVFZ). The Fish Springs fault is the northwest strand in a 3-km-wide left echelon step of the OVFZ which bounds the Poverty Hills bedrock high. The Fish Springs fault strikes approximately north-south, dips steeply to the east, and is marked by a prominent east-facing scarp. No other faults in the OVFZ have prominent east-facing scarps at the latitude of Fish Springs, which indicates that the Fish Springs fault has accommodated virtually all of the local late Quaternary vertical displacement on the OVFZ.
The Fish Springs fault exhibits normal dip slip with no measurable lateral slip. Vertical displacements of a Late Pleistocene (0.314 ± 0.036 Ma, 2σ) cinder cone and of an overlying Tahoe-age (0.065–0.195 m.y.) alluvial fan are 76±8 m and 31±3 m, respectively. The maximum vertical 3.3. m. Two nearly equal vertical displacements of the active stream channel in the Tioga-age fan total 2.2. m. Vertical displacement of a stream terrace incised into the cinder cone is 1.2 ± 0.3 m. The minute amount of incision into that terrace indicates that uplift of the terrace probably occurred during the 1872 Owens Valley earthquake.
Three displacements of 1.1 ± 0.2 m each apparently have occurred at the Tioga-age fan since the midpoint of the Tioga interval, allowing an average recurrence interval of 3500 to 9000 years. Based on the age and displacement of the cinder cone, the average late Quaternary vertical displacement rate is 0.24 ± 0.04 mm/yr (2σ). At this rate, and assuming an average vertical displacement of 1.1 ± 0.2 m per event, the average recurrence interval would be 4600 ± 1100 years (2σ). The recurrence interval for the Fish Springs fault is similar to that for a strand in the southern part of the OVFZ which also ruptured in 1872.
Right-lateral, normal oblique slip characterizes the OVFZ. The location of the Poverty Hills bedrock high at a left step in the north-northwest-striking fault zone is consistent with the style of slip of the zone. The pure normal slip on the north-striking Fish Springs fault and the alignment of local cinder cones along north-striking normal faults indicate that the late Quaternary maximum horizontal compression has been oriented north-south at the north end of the OVFZ. Data from southern Owens Valley indicate a similar stress regime there. Late Quaternary slip on the OVFZ is consistent with north-south maximum horizontal compression. 相似文献