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1.
高台车站断裂全新世活动特征   总被引:8,自引:0,他引:8  
高台车站断裂属于河西走廊内次级隆起——榆木山隆起北侧断裂系的组成部分,它位于榆木山北缘断裂北侧6km、是与榆木山隆起有成生联系、活动时间比北缘断裂更新的现代活动断裂。高台车站断裂呈向北北东略微凸出的弧形,走向总体为北西向,倾向南西,自南东向北西走向由北西向渐变为北西西、甚至近东西向,倾角自中等变化为低角度。高台车站断裂的活动性质在剖面上表现为南西盘向上逆冲为主、水平位移不明显,在近两万年以来的晚更新世晚期—全新世期间,该断裂可能发生过5期明显的新构造活动,活动时间具有自东向西逐渐变新的迁移性特点,最新一次在2.0~3.0ka左右,与高台地震时间是吻合的,它是高台地震的发震构造。  相似文献   

2.
自中三叠世扬子与华北板块发生碰撞—深俯冲作用以来,大别造山带南界上的襄樊—广济断裂带主要经历过两次变形事件: 1)早期变形事件发生在中三叠世末—晚三叠世初的造山带折返阶段,表现为造山带南边界上的韧性剪切带。这期北西—南东走向的剪切带向南西陡倾,发育北西—南东向的矿物拉伸线理,主要为右行走滑的运动性质,属于造山带斜向折返的侧边界走滑剪切带。造山带折返过程中将前陆褶断带北缘原先东西向褶皱改造为北西—南东走向。2)晚期变形事件发生在晚侏罗世,表现为脆性逆冲断层,使得前陆褶断带向北东逆冲在造山带南缘之上,同时在前陆上形成了一系列的逆冲断层。该断裂带的晚期逆冲活动与郯庐断裂带左行平移同时发生,代表了滨太平洋构造活动的开始。  相似文献   

3.
新民堡断裂新构造活动特征   总被引:11,自引:1,他引:11  
新民堡断裂属于河西走廊西段酒西盆地内断裂系的组成部分,位于嘉峪关以西40km的新民堡一带。新民堡断裂呈北西西向延伸,长8.0km,走向299°,倾向南西,倾角20°~35°。断裂下部主要发育在新近系红色泥岩中,地表穿切上更新统和全新统,变形性质以蠕滑变形为主,活动方式属于逆冲推覆;新民堡断裂在距今69.3ka与35.4ka之间、距今28.3ka左右,距今4.4ka左右发生过新构造活动。断裂位移速率为0.54~0.90mm/a,其中垂直位移速率为0.26~0.50mm/a。同时,以新民堡断裂为代表的低角度逆冲推覆断裂是造成酒西盆地及河西走廊横向压缩的重要因素和表现形式之一。  相似文献   

4.
河西走廊西段南北向左行逆冲活动断裂的发现及其意义   总被引:1,自引:0,他引:1  
陈柏林 《地质学报》2009,83(7):937-945
在河西走廊西段酒西盆地中心偏北部的阴洼山西侧发现了南北走向的阴洼山西缘左行逆冲断裂。该断裂长约4km,近南北走向,倾向东,倾角中等,是发育于北西向阴洼山右行逆冲断裂近北西端部附近的一条次级活动断裂。沿该断裂奥陶系灰绿色浅变质砂岩逆冲于白垩系紫红色砂砾岩、新近系桔红色泥岩和晚第四纪上更新世末期松散坡积层(热释光年龄10,3ka)之上。在剖面上断裂表现为自东向西的逆冲作用,其最新一次新构造活动时间在全新世中晚期(距今3~5ka)。在平面上该断裂断错自东向西从阴洼山山体流向西侧低丘斜坡戈壁地带的小冲沟致使冲沟呈“S”形拐折,反映出断裂具有明显的左行走滑。该断裂沿断层面的左行斜冲总位移达3000m,其中垂向位移为1800m左右,与阴洼山断裂垂向位移及阴洼山隆升幅度相当。该断裂的形成是阴洼山断裂右行逆冲活动所引起的局部构造应力场作用的结果,也对阴洼山断裂右行逆冲所形成的巨大位移在短距离内起到了消减和平衡作用。  相似文献   

5.
榆木山北缘断裂位于河西走廊中段榆木山山前,是榆木山隆起与河西走廊之间的分界断裂。研究榆木山北缘断裂的断错地貌与活动特征,有助于进一步了解该地区的地震危险性及历史地震的归属问题。本研究通过遥感影像解译、野外地质调查及无人机航空摄影测量,获得了研究点高精度DEM数据,并利用数据进行了微地貌分析,详细区分了榆木山北缘断裂被断错及未断错的洪积扇,根据断错特征使用14C测年方法对洪积扇进行了定年,对榆木山北缘断裂最新地震事件进行了限定。结果表明,榆木山北缘断裂未断错的早期洪积扇年代为2775~2940 cal.a B. P.,表明断裂最新一次地震活动发生在2775~2940 cal.a B. P.之前。综合前人研究结果,榆木山北缘断裂的最新一次地震事件限定在约2775~2940 cal.a B. P.至3940~4155 cal.a B. P.之间,该结果不支持公元180年表氏(高台)7级地震发生在榆木山北缘断裂上的观点。榆木山北缘断裂古地震离逝时间较长,已接近或超过地震复发间隔,具有较高的地震危险性。  相似文献   

6.
嘉峪关断裂晚第四纪新构造活动特征   总被引:2,自引:1,他引:1  
嘉峪关活动断裂位于嘉峪关市, 是与河西走廊中3个斜向隆起之一的嘉峪关-文殊山隆起密切相关的活动断裂, 也是祁连山北缘-河西走廊活动断裂体系的组成部分。该断裂走向320°, 呈线状延伸; 断裂切错前白垩系、白垩系、新近系和上更新统; 在剖面上断裂表现为南西盘上升、北东盘下降, 平面上表现为明显的右行走滑运动。晚更新世晚期~全新世存在5期明显的新构造活动, 分别发生于距今稍大于4.3ka、稍大于12.9ka、20.0~23.2ka、35.5~45ka和稍大于58.1ka。断裂粘滑活动为主, 并具明显古地震特点。   相似文献   

7.
甘肃北山南缘断裂的活动特征及其意义   总被引:2,自引:0,他引:2  
云龙  张进  徐伟  刘志成 《地质论评》2019,65(4):825-838
在河西走廊北侧,北山南缘发现活动断裂,称之为北山南缘断裂。该断裂位于金塔县城北侧,距县城约50 km。断裂全长约18 km,整体呈近东西向,倾向北西,倾角60°~80°。该断裂晚第四纪以来的活动形成了一系列断错地貌,断裂走滑运动使得多条冲沟发生同步肘状水平位错,位错量4. 5~6. 2 m,平均位错量5. 2 m。断裂的北向逆冲形成清晰的线性陡坎,陡坎落差0. 2~1. 4 m。探槽揭露了至少2次快速滑动事件,较老的一次发生于距今30 ka之前,较新的一次发生在距今8. 4~3. 3 ka。结合卫星影像、地貌和探槽等证据,认为该断裂在晚更新世和全新世有过活动,为一条以左旋走滑为主,兼有逆冲分量的活动断裂。该断裂的活动可能揭示了青藏高原东北缘的扩展已穿越河西走廊,进入北山地区。  相似文献   

8.
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。  相似文献   

9.
河西走廊榆木山边缘断层构造地貌研究   总被引:6,自引:0,他引:6  
河西走廊位于青藏高原的东北部边缘,是青藏高原向东北推挤过程中形成的一个前陆盆地系。榆木山是位于河西走廊前陆盆地系中张掖盆地和酒东盆地之间的横向隆起山地。根据野外断层露头和地貌体的变形测量和分析,本文认为榆木山北缘断层是一条具有左旋位移的逆断层,东缘断层是一条具有右旋位移的逆断层,这两条断层在全新世期间都有明显的活动。榆木山的发育是沿着北缘断层和东缘断层的逆冲活动,造成山体内地块叠加变形的结果。   相似文献   

10.
在龙门山中段小鱼洞地区映秀-北川断裂和彭县-灌县断裂发生了同震位移,同时在该地区新出现了一条北西向的同震破裂带——小鱼洞断裂的破裂带,并分割了两条近于平行的北东向逆冲-走滑型的主断裂。汶川特大地震发生后重点对小鱼洞断裂的地表破裂开展了详细的野外地质填图,利用全站仪和GPS对地表破裂进行了精确的测量。初步调查的结果表明,小鱼洞断裂位于映秀-北川断裂与彭县-灌县断裂之间,走向近于北西向,延伸约15km,以脆性破裂为特征,穿过小鱼洞大桥,并切割了多种类型的地貌单元,使道路发生拱曲、破坏和桥梁垮塌或移位。单个破裂长度在几米到300m不等,其南西盘为上升盘,北东盘为下降盘,平均垂直位错为1.0m,平均水平位错为2.3m,垂直与水平位错量之比1 ∶1~1 ∶2,显示为逆冲分量小于或等于左旋走滑分量,并以左旋走滑作用为主。同时,研究表明小鱼洞断裂属于映秀-北川断裂与彭县-灌县断裂之间的捩断层,其主要特征包括: 1)是在汶川地震中由于龙门山逆冲体之间的差异逆冲运动过程中而形成的断裂; 2)其走向近于北西向,垂直于龙门山北东向的主干断裂,而平行于逆冲体的逆冲运动方向; 3)具有高角度断面的断层,以左旋走滑作用为主。  相似文献   

11.
东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。  相似文献   

12.
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.  相似文献   

13.
郯庐断裂南段研究进展与断裂性质讨论   总被引:13,自引:3,他引:13  
据1:5万区域地质调查和专题研究资料,就郯庐断裂带是否南延与消失的原因,其与大别—苏鲁造山带交截形成的假位错效应,以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上,讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。  相似文献   

14.
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.  相似文献   

15.
某高速公路下伏煤矿采空区稳定性分析   总被引:10,自引:0,他引:10  
在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。   相似文献   

16.
塘口水电站大坝基础座落在断层和裂隙较发育的龟裂纹灰岩上,岩体完整性差、透水性强,多年运行后,大坝灌浆廊道和排水廊道出现多处集中性漏水,为确保大坝安全和电站正常发电,根据渗漏性质和成因,采用对灌浆廊道补充帷幕灌浆,对排水廊道进行固结+帷幕+回填灌浆。通过灌浆处理后,效果良好,表明灌浆工程有效的将导致坝基渗漏的上下游的裂隙通道封闭,并顺利的经受了随后的汛期洪水考验,大坝安全得到保障。  相似文献   

17.
The Global Stratotype Section and Point (GSSP) for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy (SSS) proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy (ICS). The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob's Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs.  相似文献   

18.
In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix.  相似文献   

19.
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.  相似文献   

20.
正Artemia cysts are an extremely important component of aquaculture diets.It is well established that the cultivation of fish and shellfish derive substantial health and growth advantages when Artemia are included in the diets of the  相似文献   

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