青藏高原北部晚第四纪应力场在遥感影像上的响应

青藏高原北部发育一系列北西向大型左行走滑断裂带,目前普遍认为这些左行走滑断裂至今仍在活动,在左行走滑作用下,青藏高原东部向东挤出并伴随强烈的地块旋转运动。本文以介于东昆仑左行走滑断裂带与玉树左行走滑断裂带之间的巴颜喀拉山中央断裂（及其周缘的构造形迹）为主要研究对象,根据断层构造的直接解译标志——清晰的线性形迹和构造地貌标志如断层陡坎、断层谷地、挤压脊、地裂缝、断层走滑造成的水系错动、新老洪积扇的侧向叠加等,在高分辨率的SPOT5及中等分辨率ETM遥感影像上对研究区内北西向活动断层与北东向活动断层的空间分布、规模、活动性质、相对活动时代及活动幅度等进行了遥感分析和野外验证,并结合对断层周缘沿共轭张裂隙展布的水系与地裂缝的规模、展布方向等的统计分析,对晚第四纪应力场进行了恢复。研究表明:北西向活动断层具右行走滑兼有逆冲运动特征,北东向活动断层具左行走滑兼有正滑运动特征,二者为晚第四纪NNE向（2°）挤压应力条件下产生的北西向与北东向走滑作用的产物。北西向右行走滑作用的发现,预示着青藏高原北部第四纪以来普遍存在的北西向左行走滑作用可能在晚更新世就已终止。在此基础上,探讨了处于不同展布方向上的湖盆在同一应力条件下表现出的不同演化趋势:即在NNE向挤压应力作用下,呈北东向展布的错坎巴昂日东湖处于近东西向拉张状态,呈北西向展布的卡巴纽尔多湖变化不明显。     

Deformation at the Easternmost Altyn Tagh Fault: Constraints on the Growth of the Northern Qinghai–Tibetan Plateau

How the Altyn Tagh fault(ATF) extends eastwards is one of the key questions in the study of the growth of the Qinghai–Tibetan Plateau. Detailed fieldwork at the easternmost part of the ATF shows that the ATF extends eastward and bypasses the Kuantan Mountain; it does not stop at the Kuantan Mountain, but connects with the northern Heishan fault in the east. The ATF does not enter the Alxa Block but extends eastward along the southern Alxa Block to the Jintanan Mountain. The Heishan fault is not a thrust fault but a sinistral strike-slip fault with a component of thrusting and is a part of the ATF. Further to the east, the Heishan fault may connect with the Jintananshan fault. A typical strike-slip duplex develops in the easternmost part of the ATF. The cut and deformed Quaternary sediments and displaced present gullies along the easternmost ATF indicate that it is an active fault. The local highest Mountain(i.e., the Kuantan Mountain) in the region forms in a restraining bend of the ATF due to the thrusting and uplifting. The northward growth of the Qinghai–Tibetan Plateau and the active deformation in South Mongolia are realized by sinistral strike-slipping on a series of NE–SW-trending faults and thrusting in restraining bends along the strike-slip faults with the northeastward motion of blocks between these faults.     

青藏高原东缘中更新世伸展作用及其新构造意义

基于区域TM遥感影像资料解译和野外构造地貌调查以及晚第四纪沉积物光释光测年分析,论述了青藏高原东缘复杂地貌边界带晚第四纪伸展构造及其构造地貌特征。结果显示,伸展构造主要见于下列几个构造带:沿南北走向的安宁河谷地、大凉山构造带、若尔盖盆地、岷江断裂带等。其典型的地貌特征表现为充填晚第四纪沉积物的狭窄河谷。根据盆地沉积物的地层时代和年龄推断,正断作用主要发生在中更新世时期,大约起始于早更新世末期(1.2～0.9Ma),结束于中更新世晚期(100～200ka)。晚更新世以来,构造体制转化为走滑—逆冲机制。青藏东缘中更新世伸展构造作用可能与该地貌边界带晚新生代造山后的高原垮塌有关。     

LATE QUATERNARY FAULTING OF JIALI FAULT

LATE QUATERNARY FAULTING OF JIALI FAULT1　ChungS ,LoC ,LeeT ,etal.DiachronousupliftoftheTibetanplateaustarting 40Myrago[J].Nature ,1998,394:76 9～773. 2　ColemanM ,HodgesK .EvidenceforTibetanplateauupliftbefore 14Myragofromanewminimumageforeast westexten sion[J].Nature ,1995 ,374:49～ 5 2 . 3　HarlandWB ,ArmstrongRL ,CoxAV ,etal.Ageologictimescale 1989[J].Cambridge ,U .K :CambridgeUnivPress,1990 . 4　HarrisonTM ,CopelandP ,KiddWSF ,etal.RaisingTibet[J].…     

依兰-伊通断裂新构造活动规律分析

作为郯庐断裂带北段主干的依兰-伊通断裂, 其新构造活动性与活动规律仍然存在不同的认识.本次工作通过详细的野外调查, 发现该断裂内活断层广泛存在, 由东、西两支北东走向的主干活断层构成, 沿着古近纪地堑边界断层发育.这些活断层主要呈破碎型结构, 多为逆右行平移活动.通过对这些活断层一系列实测擦痕反演应力场, 显示它们多是在东西向挤压中活动的, 而现今应力场转变为北东东-南西西向区域性挤压.依据本次野外观察与¹⁴ C定年, 并结合前人定年结果与近代地震分布, 表明依兰-伊通西支活断层的最新活动时代为全新世与晚更新世相间, 而东支活断层的最新活动时代主要为早-中更新世.依兰-伊通断裂内活断层显示了明显的差异性活动, 表现为西支的活动强度明显大于东支, 西支的最新活动时代皆晚于东支, 沿走向上活动性强、弱相间与最新活动时代不断变化, 以及近代地震活动不均一分布.它们沿走向上的分段性、差异性活动主要是因为被一系列北西向断层切断所致.     

Orientations of palaeotectonic features as a key to understanding the neotectonic block rotation of the Kocaeli peninsula,NW Turkey

Due to northward subduction of Neotethys, the ?stanbul zone collided with the Sakarya zone in northwest Turkey during the early Eocene. Subsequently, this region was subjected to compressional forces during the late Eocene–early Miocene period. Folds, thrusts and reverse faults developed approximately parallel to long axes of the ?stanbul zone. NNW–SSE oriented conjugate strike‐slip faults developed with continued contraction. In addition to the orientations of palaeotectonic features, the morphotectonic, stratigraphic and seismic characteristics expose differences between the northeastern Marmara peneplain and the southern Black Sea highland. This study reports causes of this diversity reflecting the neotectonic evolution of the ?stanbul zone. The diversity is related to the clockwise rotation of the Kocaeli peninsula between two dextral zone‐bounding faults and two sinistral block‐bounding faults. The principle factors of this process were the development of the North Anatolian fault zone (NAFZ) and the related evolution of the Adapazar?–Karasu fault zone (AKFZ), the Bosphorus fault zone (BFZ) and the Northern Boundary fault (NBF).     

丹江断裂东段第四纪活动性及地震地质涵义

丹江口地区地震地质因修建丹江水库而得到深入研究,但针对断裂进行的系统性研究较少。通过对丹江断裂东段进行1：1万大比例条带状活动断裂填图,综合采用地质地貌调查、岩样年龄测试、地质钻探、浅层地震勘探等多种手段进行研究,认为：1）丹江断裂东段第四纪以来累积左旋走滑量在250~500 m之间,上更新统地层垂直断距为10~20 m;2）断裂最新活动时代为晚更新世,活动性质以由NE向SW的逆冲为主,兼具有左旋走滑分量;3）断裂活动性由山地向盆地迁移。丹江断裂晚更新世以来活动表明,南襄盆地西缘活动性较强。该认识可为进一步评估丹江口地区乃至南襄盆地西缘的地震构造环境提供依据。     

四川攀西地区晚新生代构造变形历史与隆升过程初步研究

基于TM遥感图像解译和野外调研，分析了攀西地区大渡河、安宁河深切河谷地貌特征和断裂带构造变形特征，建立了安宁河断裂带晚新生代5阶段变形历史。研究表明，中新世晚期—上新世早期，安宁河断裂以挤压走滑活动为主；上新世晚期至早更新世时期，断裂以斜张走滑活动为主，活动强度较弱；早中更新世之间发生的元谋运动使昔格达组湖相地层褶皱变形；中晚更新世时期发生断陷作用，形成安宁河两堑夹—垒的构造格局；晚更新世—全新世时期又以左旋走滑活动为主。综合安宁河、大渡河河谷地貌和晚新生代地层记录和变形特征，提出了攀西高原晚新生代4阶段隆升模式：中新世早中期(12Ma之前)以缓慢隆升与区域夷平化作用为主，中新世晚期—上新世早期(12～3．4Ma)是高原快速隆升与河流强烈下切的时期，上新世晚期—早更新世(3．4～1.1Ma)为昔格达湖盆发育时期，中晚更新世—全新世(1．1Ma以来)是高原快速隆升与河谷阶地发育时期。最后指出，至上新世晚期(3．4Ma以前)，攀西高原海拔高度可能超过了3000m。     

THE LATE QUATERNARY RIGHT LATERAL STRIKE-SLIPPING OF ZHONGDIAN—DAJU FAULT IN NORTHWEST YUNNAN, CHINA

THE LATE QUATERNARY RIGHT LATERAL STRIKE-SLIPPING OF ZHONGDIAN—DAJU FAULT IN NORTHWEST YUNNAN, CHINAthesubject“TherecentdisplacementandDynamicsoflithosphereintheQinghai XizangPlateau”ofnation alclimbingproject“Therecentdisp     

赣江断裂带中生代的演化及其地球动力学背景

赣江断裂带是江西省境内醒目的北北东向平移断裂构造带,由一系列北北东向、北东向和北西向断裂束组成,表现为一个大规模的左行走滑脆性剪切带并兼具伸展断陷和右旋走滑的成份。赣江断裂带在重力、航磁异常呈现为显著的梯度带,是一条晚中生代的岩浆岩带,控制了以鄱阳盆地为代表的一系列白垩纪-古近纪沉积盆地的形成与发育。该带在中生代的演化可分为早-中侏罗世压扭、晚侏罗早-白垩世左行平移和晚白垩世上盘斜落的右行平移3个阶段。在侏罗纪以来太平洋板块对欧亚大陆斜向俯冲的大背景下,赣江断裂带的形成和演化与华南广为发育的燕山期陆内造山作用密切相关,北北东向断裂的发育则直接受郯庐断裂早白垩世左行走滑活动控制,因而表现出“北强南弱”和“北早南晚”的特点。白垩纪时赣江断裂的活动方式与郯庐断裂一致,可认为是后者的南延。     

岷江断裂带晚新生代逆冲推覆构造：来自钻孔的证据

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。     

郯庐断裂带的最大左行走滑断距及其形成时期

作者采用断裂带两盘地壳变形速度的估算方法,求得郯庐断裂带最大左行走滑断距为３９０ｋｍ;根据中朝地块南缘断裂被错断的现象来判断,最大左行走滑断距为４３０ｋｍ;采用古地磁学方法求得最大左行走滑断距约为３００－４００ｋｍ。最大左行走滑活动时期当在中晚三叠世。侏罗纪时期郯断裂带为逆断层,白垩纪时期的走滑活动量不大于１００ｋｍ,早第三纪的走滑断距不明显,晚第三纪－早更新世可能有５０ｋｍ左右的左行走滑断距,新构造期（<0.73Ma以来)的右行走滑断距小于lOOm。     

小江断裂带有三纪走滑断陷盆地的充填层序特征

小江断裂是滇中走滑断裂系中的一条主干断裂，沿断裂带发育了一系列带有明显走滑特征的新生代小型断陷盆地，第三纪含煤地层主要由冲积扇－湖泊、沼泽成因地层层序构成。本在对多个断陷盆地的成因地层、充填序列、沉积体系域等剖析的基础上，讨论了走滑构造背景下断陷盆地的充填层序特征，并指出构造沉降、走滑作用和构造反转对盆地充填起作重要的作用。     

维西-乔后断裂新活动特征及其与红河断裂的关系

根据野外调查结果,重点阐述了维西-乔后断裂晚第四纪活动特征,并对其与红河断裂之间的关系进行了探讨分析。维西-乔后断裂对晚新生代盆地具有明显的控制作用,右旋走滑特征明显,沿线山脊和河流表现为同步右旋位错。德胜和长邑南探槽揭示其断错了晚更新世晚期-全新世堆积。岩曲-石岩村一带Ⅱ级河流阶地和后缘洪积扇上发育长约3 km、高2.5 m左右的断层陡坎。根据洪积扇、冲沟和河流阶地位错量估算,该断裂晚更新世晚期以来右旋水平滑动速率为1.8~2.4 mm/a,垂直滑动速率为0.30~0.35 mm/a。它南与红河断裂相连,北与金沙江断裂相接,新生代以来具有与红河断裂和金沙江断裂相似的运动学特征、相同的地质演化历史和构造变形机制,是红河活动断裂的北延部分。维西-乔后断裂与红河、金沙江以及德钦-中甸-大具等断裂一起,共同构成了川滇活动块体的西部边界。      

Late Quaternary Slip-rates and Slip Partitioning on the Southeastern Xianshuihe Fault System,Eastern Tibetan Plateau

Quantitative analysis of the kinematics of the active faults distributed around the Qinghai-Tibetan Plateau is critical to understand current tectonic processes of the plateau. Chronological analysis, based on the comparison among regional climate and geomorphology, digital photogrammetry, offset landforms, and the tectonics were adopted in this study on the Xianshuihe fault in the eastern Tibetan plateau. Two or more offset-age data were obtained for each segment of the Xianshuihe and the Yunongxi faults. The offset landforms, including river terrace, alluvial fan and glacial moraine, provide constraints for the late Quaternary slip rate of the Xianshuihe fault. The left-lateral strike slip rate of the Xianshuihe fault decreases from 17 mm/a on the northwest segment to 9.3 mm/a on the southeast segment. Regarding the Xianshuihe fault zone and its adjacent blocks as a regional tectonic system, vector analysis was used to quantitatively analyze the longitudinal kinematical transformation and transversal slip partitioning on the fault zone in terms of the kinematical parameters of the main faults within the zone. The results show that there is a distributed vertical uplift at a rate of 6.1 mm/yr caused by shortening across the Gongga Mountains region. Based on these results, we established a model of the slip partitioning for the southeastern segment of the Xianshuihe fault zone.     

Mountain front migration and drainage captures related to fault segment linkage and growth: The Polopos transpressive fault zone (southeastern Betics,SE Spain)

The Polopos E–W- to ESE–WNW-oriented dextral-reverse fault zone is formed by the North Alhamilla reverse fault and the North and South Gafarillos dextral faults. It is a conjugate fault system of the sinistral NNE–SSW Palomares fault zone, active from the late most Tortonian (≈7 Ma) up to the late Pleistocene (≥70 ky) in the southeastern Betics. The helicoidal geometry of the fault zone permits to shift SE-directed movement along the South Cabrera reverse fault to NW-directed shortening along the North Alhamilla reverse fault via vertical Gafarillos fault segments, in between. Since the Messinian, fault activity migrated southwards forming the South Gafarillos fault and displacing the active fault-related mountain-front from the north to the south of Sierra de Polopos; whilst recent activity of the North Alhamilla reverse fault migrated westwards. The Polopos fault zone determined the differential uplift between the Sierra Alhamilla and the Tabernas-Sorbas basin promoting the middle Pleistocene capture that occurred in the southern margin of the Sorbas basin. Continued tectonic uplift of the Sierra Alhamilla-Polopos and Cabrera anticlinoria and local subsidence associated to the Palomares fault zone in the Vera basin promoted the headward erosion of the Aguas river drainage that captured the Sorbas basin during the late Pleistocene.     

中国东西部地貌边界带晚新生代构造变形历史与青藏高原东缘隆升过程初步研究

中国东西部地貌边界带横跨青藏高原东部与扬子地块,成为我国大陆Ⅰ级构造地貌陡变带和地球物理变异带。根据地表构造形迹的组合特征,地貌边界带由3个主要形变系统组成,从北到南它们是:东昆仑—岷山左旋走滑-冲断系统、龙门山—龙泉山冲断-推覆系统、鲜水河—安宁河左旋走滑-冲断系统等。在综合分析各构造系统的组成、变形特征、变形年代学和演化过程等基础上,提出了青藏东缘晚新生代阶段性构造演化模式。指出,晚中新世至早上新世时期,强烈的走滑-冲断变形主要发生在地貌边界带中南段,导致鲜水河—安宁河走滑-冲断系统和龙门山—龙泉山冲断-推覆系统的形成和发展,而东昆仑—秦岭断裂系则以走滑伸展变形为主,沿西秦岭构造带发育走滑拉分盆地和幔源火山喷发活动。晚上新世—早更新世时期,构造运动性质发生了南北反转,强烈的走滑挤压活动主要集中在北段东昆仑—岷山走滑-冲断系统,岷山隆起带在此时期强烈活动而快速崛起;青藏高原东南缘鲜水河—安宁河走滑断裂系统则以走滑伸展变形为主,在深切河谷中发育了昔格达河湖相沉积。中更新世以来,构造形变系统以挤压剪切为主,兼具正向倾滑活动,局部发生断陷作用。基于攀西地区深切河谷的构造地貌分析,提出了青藏东南缘晚新生代4-阶段隆升模式。     

Active Faulting Pattern,Present‐day Tectonic Stress Field and Block Kinematics in the East Tibetan Plateau

Abstract: This paper examines major active faults and the present-day tectonic stress field in the East Tibetan Plateau by integrating available data from published literature and proposes a block kinematics model of the region. It shows that the East Tibetan Plateau is dominated by strike-slip and reverse faulting stress regimes and that the maximum horizontal stress is roughly consistent with the contemporary velocity field, except for the west Qinling range where it parallels the striking of the major strike-slip faults. Active tectonics in the East Tibetan Plateau is characterized by three faulting systems. The left-slip Kunlun-Qinling faulting system combines the east Kunlun fault zone, sinistral oblique reverse faults along the Minshan range and two major NEE-striking faults cutting the west Qinling range, which accommodates eastward motion, at 10–14 mm/a, of the Chuan-Qing block. The left-slip Xianshuihe faulting system accommodated clockwise rotation of the Chuan-Dian block. The Longmenshan thrust faulting system forms the eastern margin of the East Tibetan Plateau and has been propagated to the SW of the Sichuan basin. Crustal shortening across the Longmenshan range seems low (2–4 mm/a) and absorbed only a small part of the eastward motion of the Chuan-Qing block. Most of this eastward motion has been transmitted to South China, which is moving SEE-ward at 7–9 mm/a. It is suggested from geophysical data interpretation that the crust and lithosphere of the East Tibetan Plateau is considerably thickened and rheologically layered. The upper crust seems to be decoupled from the lower crust through a décollement zone at a depth of 15–20 km, which involved the Longmenshan fault belt and propagated eastward to the SW of the Sichuan basin. The Wenchuan earthquake was just formed at the bifurcated point of this décollement system. A rheological boundary should exist beneath the Longmenshan fault belt where the lower crust of the East Tibetan Plateau and the lithospheric mantle of the Yangze block are juxtaposed.     

Late Quaternary Activity of the Huashan Piedmont Fault and Associated Hazards in the Southeastern Weihe Graben, Central China

The Weihe Graben is not only an important Cenozoic fault basin in China but also a significant active seismic zone. The Huashan piedmont fault is an important active fault on the southeast side of the Weihe Graben and has been highly active since the Cenozoic. The well–known Great Huaxian County Earthquake of 1556 occurred on the Huashan piedmont fault. This earthquake, which claimed the lives of approximately 830000 people, is one of the few large earthquakes known to have occurred on a high–angle normal fault. The Huashan piedmont fault is a typical active normal fault that can be used to study tectonic activity and the associated hazards. In this study, the types and characteristics of late Quaternary deformation along this fault are discussed from geological investigations, historical research and comprehensive analysis. On the basis of its characteristics and activity, the fault can be divided into three sections, namely eastern, central and western. The eastern and western sections display normal slip. Intense deformation has occurred along the two sections during the Quaternary; however, no deformation has occurred during the Holocene. The central section has experienced significant high–angle normal fault activity during the Quaternary, including the Holocene. Holocene alluvial fans and loess cut by the fault have been identified at the mouths of many stream valleys of the Huashan Mountains along the central section of the Huashan piedmont fault zone. Of the three sections of the Huashan piedmont fault, the central section is the most active and was very active during the late Quaternary. The rate of normal dip–slip was 1.67–2.71±0.11 mm/a in the Holocene and 0.61±0.15 mm/a during the Mid–Late Pleistocene. As is typical of normal faults, the late Quaternary activity of the Huashan piedmont fault has produced a set of disasters, which include frequent earthquakes, collapses, landslides, mudslides and ground fissures. Ground fissures mainly occur on the hanging–wall of the Huashan piedmont fault, with landslides, collapses and mudslides occurring on the footwall.     

Thermal Evolution of the Tanlu Fault Zone on the Eastern Margin of the Dabie Mountains and Its Tectonic Implications

Five samples of muscovite from mylonites of the earlier Tanlu ductile shear zone on the eastern margin of the Dabie Mountains yield 40Ar/39Ar ages ranging from 178 Ma to 196 Ma. Three of them have reliable plateau ages of 188.7±0.7 Ma, 189.7±0.6 Ma and 192.5±0.7 Ma respectively, which indicates a syn-orogenic, sinistral strike-slip thermal event. This displacement movement derived from the continent-continent collision of the North and South China blocks took place in the Early Jurassic and after uplifting of high-pressure to ultrahigh-pressure slabs to the mid-crust. It is suggested that during the collision the Tanlu fault zone was an intracontinental transform fault caused by differential subduction speeds. The 40Ar/39Ar ages of mylonite whole-rock and muscovite from the later Tanlu ductile shear zone suggest another sinistral strike-slip cooling event at 128 Ma. During this strike-slip faulting, large-scale intrusion and doming uplift occurred in the eastern part of the Dabie orogenic belt. Data o