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1.
《Geodinamica Acta》2001,14(1-3):177-195
The east Anatolian plateau and the Lesser Caucasus are characterised and shaped by three major structures: (1) NW- and NE-trending dextral to sinistral active strike-slip faults, (2) N-S to NNW-trending fissures and /or Plio-Quaternary volcanoes, and (3) a 5-km thick, undeformed Plio-Quaternary continental volcano-sedimentary sequence accumulated in various strike-slip basins. In contrast to the situation in the east Anatolian plateau and the Lesser Caucasus, the Transcaucasus and the Great Caucasus are characterised by WNW-trending active thrust to reverse faults, folds, and 6-km thick, undeformed (except for the fault-bounded basin margins) continuous Oligocene-Quaternary molassic sequence accumulated in actively developing ramp basins. Hence, the neotectonic regime in the Great Caucasus and the Transcaucasus is compressional–contractional, and Oligocene-Quaternary in age; whereas it is compressional–extensional, and Plio-Quaternary in age in the east Anatolian plateau and the Lesser Caucasus.Middle and Upper Miocene volcano-sedimentary sequences are folded and thrust-to-reverse-faulted as a result of compressional–contractional tectonic regime accompanied by mostly calc-alkaline volcanic activity, whereas Middle Pliocene-Quaternary sequences, which rest with angular unconformity on the pre-Middle Pliocene rocks, are nearly flat-lying and dominated by strike-slip faulting accompanied by mostly alkali volcanic activity implying an inversion in tectonic regime. The strike-slip faults cut and displace dykes, reverse to thrust faults and fold axes of Late Miocene age up to maximum 7 km: hence these faults are younger than Late Miocene, i.e., these formed after Late Miocene. Therefore, the time period between late Serravalian (∼ 12 Ma) continent–continent collision of Arabian and Eurasian plates and the late Early Pliocene inversion in both the tectonic regime, basin type and deformation pattern (from folding and thrusting to strike-slip faulting) is here termed as the Transitional period.Orientation patterns of various neotectonic structures and focal mechanism solutions of recent earthquakes that occurred in the east Anatolian plateau and the Caucasus fit well with the N–S directed intracontinental convergence between the Arabian plate in the south and the Eurasian plate in the north lasting since Late Miocene or Early Pliocene in places. 相似文献
2.
The study area is the Van earthquake region. It is located in the western section of the East Anatolian–Iranian plateau outside and to the east of the Karlıova triple junction. Based on the tectonic periods, the rock units exposed in the study area are classified into two common categories. These are the Pre-Late Pliocene paleotectonic units and the Plio-Quaternary neotectonic units. The Paleotectonic units are composed of the Yüksekova Complex of Campanian–Maastrichtian age and the Kırkgeçit Formation of Oligo-Miocene age. The paleotectonic units are intensely deformed (folded, thrust to reverse faulted and converted into an imbricate stack). The neotectonic units are composed of fluvio-lacustrine sedimentary facies with volcanic interclations. It is full of soft-sedimentary structures such as deltaic structure, slump fold, sand dikes to sills and normal to reverse types of growth faults which imply to a sedimentation accompanied by both a volcanic activity and active tectonics. Originally the Paleotectonic units are overlain with an angular unconformity by the nearly flat-lying neotectonic units. This angular unconformity and the big difference in the deformational patterns of both categories of rock units indicate an inversion in tectonic regime in Late Pliocene. The new tectonic regime is the strike-slip faulting-dominated neotectonic regime. It is governed by an approximately N–S-directed compression, and composed of NW- to NE-trending strike-slip faults, N–S trending oblique-slip normal faults to fissures and the E–W trending thrust to reverse faults. Most of thrust to reverse faults are inherited from the Pre-Late Pliocene paleotectonic regime. Some of them have reactivated and led to the occurrence of large and devastative earthquakes. The last devastative seismic event is the 23 October 2011 Tabanlı (Van) earthquake of Mw = 7.2 that caused 644 deaths and moderate to heavy damage of ¼ of structures (28,532) in Van earthquake region. The source of the Tabanlı earthquake is the Everek erosional reverse fault. In addition the Tabanlı earthquake is the largest seismic event occurred till now in Turkey. It was followed by a series (over 6000) of small-sized aftershocks and severeal moderate-sized indepentent earthquakes of reverse, normal and strike-slip faulting origin. Both the field and new seismic data strongly reveal that the prominent tectonic regime in the East Anatolian plateau is the strike-slip neotectonic regime, not the tensional tectonic regime as has been reported in some previous works. The strike-slip faulting and related deformation are confined into the upper shallowing part (up to 40 km) of the crust, whilst the extensional deformations are the subcrustal processes and being taking place in a squashy zone at the depths of approximately 40–60 km. 相似文献
3.
Kadir Dirik 《Geodinamica Acta》2013,26(1-3):147-158
AbstractCentral Anatolia has undergone complex Neotectonic deformation since Late Miocene-Pliocene times. Many faults and intracontinental basins in this region were either formed, or have been reactivated, during this period. The eastern part of central Anatolia is dominated by a NE-SW-trending, left lateral transcurrent structure named the Central Anatolian fault zone located between Sivas in the northeast and west of Mersin in the southwest. Around the central part, it is characterized by transtensional depressions formed by left stepping and southward bending of the fault zone. Pre-Upper Miocene basement rocks of the region consist of the central Anatolian crystalline complex and a sedimentary cover of Tertiary age. These rock units were strongly deformed by N-S con- vergence. The entire area emerged to become the site of erosion and formed a vast plateau before the Late Miocene. A NE-SW- trending extensional basin developed on this plateau in Late Miocene-Early Pliocene times. Rock units of this basin are characterized by a thick succession of pyroclastic rocks intercalated with calcalkaline-alkaline volcanics. The volcanic sequence is uncon- formably overlain by Pliocene lacustrine-fluviatile deposits interrelated with ignimbrites and tuffs. Thick, coarse grained alluvial/colluvial fan deposits of marginal facies and fine grained elastics and carbonates of central facies display characteristic synsedimentary structures with volcanic intercalations. These are the main lines of evidence for development of a new transtensional H?rka— k?zd?rmak basin in Pliocene times. Reactivation of the main segment of the Central Anatolian fault zone has triggered development of depressions around the left stepping and southward bending of the central part of this sinistral fault zone in the ignimbritic plateau during Late Pliocene-Quaternary time. These transtensional basins are named the Tuzla Gölü and Sultansazl??? pull-apart basins. The Sultansazl??? basin has a lazy S to rhomboidal shape and displays characteristic morphologic features including a steep and stepped western margin, large alluvial and colluvial fans, and a huge composite volcano (the Erciyes Da??).The geometry of faulting and formation of pull-apart basins can be explained within the framework of tectonic escape of the wedgelike Anatolian block, bounded by sinistral East Anatolian fault zone and dextral North Anatolian transform fault zone. This escape may have been accomplished as lateral continental extrusion of the Anatolian Plate caused by final collision of the Arabian Plate with the Eurasian Plate. © 2001 Éditions scientifiques et médicales Elsevier SAS 相似文献
4.
《Geodinamica Acta》2001,14(1-3):147-158
Central Anatolia has undergone complex Neotectonic deformation since Late Miocene–Pliocene times. Many faults and intracontinental basins in this region were either formed, or have been reactivated, during this period. The eastern part of central Anatolia is dominated by a NE–SW-trending, left lateral transcurrent structure named the Central Anatolian fault zone located between Sivas in the northeast and west of Mersin in the southwest. Around the central part, it is characterized by transtensional depressions formed by left stepping and southward bending of the fault zone.Pre-Upper Miocene basement rocks of the region consist of the central Anatolian crystalline complex and a sedimentary cover of Tertiary age. These rock units were strongly deformed by N–S convergence. The entire area emerged to become the site of erosion and formed a vast plateau before the Late Miocene. A NE–SW-trending extensional basin developed on this plateau in Late Miocene–Early Pliocene times. Rock units of this basin are characterized by a thick succession of pyroclastic rocks intercalated with calcalkaline–alkaline volcanics. The volcanic sequence is unconformably overlain by Pliocene lacustrine–fluviatile deposits intercalated with ignimbrites and tuffs. Thick, coarse grained alluvial/colluvial fan deposits of marginal facies and fine grained clastics and carbonates of central facies display characteristic synsedimentary structures with volcanic intercalations. These are the main lines of evidence for development of a new transtensional Hırka–Kızılırmak basin in Pliocene times. Reactivation of the main segment of the Central Anatolian fault zone has triggered development of depressions around the left stepping and southward bending of the central part of this sinistral fault zone in the ignimbritic plateau during Late Pliocene–Quaternary time. These transtensional basins are named the Tuzla Gölü and Sultansazlığı pull-apart basins. The Sultansazlığı basin has a lazy S to rhomboidal shape and displays characteristic morphologic features including a steep and stepped western margin, large alluvial and colluvial fans, and a huge composite volcano (the Erciyes Dağı).The geometry of faulting and formation of pull-apart basins can be explained within the framework of tectonic escape of the wedge-like Anatolian block, bounded by sinistral East Anatolian fault zone and dextral North Anatolian transform fault zone. This escape may have been accomplished as lateral continental extrusion of the Anatolian Plate caused by final collision of the Arabian Plate with the Eurasian Plate. 相似文献
5.
《Geodinamica Acta》2001,14(1-3):3-30
Turkey forms one of the most actively deforming regions in the world and has a long history of devastating earthquakes. The better understanding of its neotectonic features and active tectonics would provide insight, not only for the country but also for the entire Eastern Mediterranean region. Active tectonics of Turkey is the manifestation of collisional intracontinental convergence- and tectonic escape-related deformation since the Early Pliocene (∼5 Ma). Three major structures govern the neotectonics of Turkey; they are dextral North Anatolian Fault Zone (NAFZ), sinistral East Anatolian Fault Zone (EAFZ) and the Aegean–Cyprean Arc. Also, sinistral Dead Sea Fault Zone has an important role. The Anatolian wedge between the NAFZ and EAFZ moves westward away from the eastern Anatolia, the collision zone between the Arabian and the Eurasian plates. Ongoing deformation along, and mutual interaction among them has resulted in four distinct neotectonic provinces, namely the East Anatolian contractional, the North Anatolian, the Central Anatolian ‘Ova’ and the West Anatolian extensional provinces. Each province is characterized by its unique structural elements, and forms an excellent laboratory to study active strike-slip, normal and reverse faulting and the associated basin formation. 相似文献
6.
《International Geology Review》2012,54(14):1803-1821
ABSTRACTIn the Central Anatolia, the style of neotectonic regime governing the region has been a controversial issue. A tectonic study was carried out in order to contribute to this issue and better understand the neotectonic stress distribution and style of deformation in the west-southwest of the Konya region. From Middle Miocene to Recent time, Konya region was part of the Central Anatolia extensional province. The present-day topography in the west-southwestern part of Konya is characterized by alternating elongate grabens and horsts trending E-W and NW-SE. The grabens were developed upon low-grade metamorphic rocks of Palaeozoic and Mesozoic ages and ophiolite slabs of possibly Late Cretaceous age. The evolutionary history of grabens is episodic as evidenced by two graben infills; older and younger graben infills separated by an angular unconformity. The older infill consists of fluviolacustrine sequence intercalated with calc-alkaline lavas and pyroclastic rocks. This infill is folded; thrust faulted and Middle Miocene-Early Pliocene in age. The younger and undeformed basin fill comprises mainly of Plio-Quaternary conglomerates, sandstone-mudstone alternations of alluvial fan and recent basin floor deposits. Three major tectonic phases were differentiated based on the detailed mapping, morphological features and kinematic analysis. Approximately N-S trending extension began in the Middle Miocene-Early Pliocene in the region with the formation of E-W and NW-SE-trending grabens. Following NE-SW-directed compression which deformed the older basin fill deposits by folding and thrusting, a second period of ENE-WSW-trending extension began in the late Pliocene and continued to the present. The west-southwestern margin of the Konya depression is bounded by the Konya Fault Zone. It is an oblique-slip normal fault with a minor dextral strike-slip component and exhibits well-preserved fault slickensides and slickenlines. Recent seismicity and fault-related morphological features reveal that the Konya Fault Zone is an active neotectonic structure. 相似文献
7.
西秦岭地区东昆仑-秦岭断裂系晚新生代左旋走滑历史及其向东扩展 总被引：17，自引：1，他引：16
要通过在TM遥感图像解译和野外观测的基础上,描述了东昆仑断裂带东段活动形迹的组成和活动断层地貌特征,阐述了甘南高原西秦岭地区新近纪拉分盆地的沉积-构造特征,提出了该区东昆仑-秦岭断裂系晚新生代左旋走滑伸展-走滑挤压-走滑伸展的3个阶段的构造变形模式。指出,中新世晚期至上新世早期,东昆仑-秦岭断裂系以左旋走滑伸展活动为主,伴随着西秦岭地区拉分盆地的形成和超基性火山岩群的发育。这期左旋走滑伸展活动向东扩展导致了渭河盆地新近纪引张应力方向由早期的NE-SW向转变为晚期的NW—SE向。上新世晚期以来(约3．4Ma以前),东昆仑-秦岭断裂系以左旋走滑挤压活动为主,导致早期拉分盆地的轻微褶皱变形,走滑挤压活动主要集中在东昆仑东段玛沁-玛曲主断裂带上。该期构造变动持续到早更新世,它的向东扩展产生了广泛的地壳形变效应,包括青藏东缘岷山隆起带的快速崛起、华北地区汾-渭地堑系的形成和发展以及郯庐断裂带右旋走滑活动等。中、晚更新世时期,断裂系以走滑伸展变形为主,主要集中在东昆仑断裂带东段3个分支上,地块向东挤出伴随着顺时针旋转。 相似文献
8.
In northwest Anatolia, there is a mosaic of different morpho-tectonic fragments within the western part of the right-lateral strike-slip North Anatolian Fault (NAF) Zone. These were developed from compressional and extensional tectonic regimes during the paleo- and neo-tectonic periods of Turkish orogenic history. A NE-SW-trending left-lateral strike-slip fault system (Adapazari-Karasu Fault) extends through the northern part of the Sakarya River Valley and began to develop within a N–S compressional tectonic regime which involved all of northern Anatolia during Middle Eocene to early Middle Miocene times. Since the end of Middle Miocene times, this fault system forms a border between a compressional tectonic regime in the eastern area eastwards from the northern part of the Sakarya River Valley, and an extensional tectonic regime in the Marmara region to the west. The extension caused the development of basins and ridges, and the incursions of the Mediterranean Sea into the site of the future Sea of Marmara since Late Miocene times. Following the initiation in late Middle Miocene times and the eastward propagation of extension along the western part of the NAF, a block (North Anatolian Block) began to form in the northern Anatolia region since the end of Pliocene times. The Adapazari-Karasu Fault constitutes the western boundary of this block which is bounded by the NAF in the south, the Northeast Anatolian Fault in the east, and the South Black Sea Thrust Fault in the north. The northeastward movement of the North Anatolian Block caused the formation of a marine connection between the Black Sea and the Aegean/Mediterranean Sea during the Pleistocene. 相似文献
9.
Insights into biaxial extensional tectonics: an examplefrom the Sandıklı Graben,West Anatolia,Turkey
West Anatolia, together with the Aegean Sea and the easternmost part of Europe, is one of the best examples of continental extensional tectonics. It is a complex area bounded by the Aegean–Cyprus Arc to the south and the North Anatolian Fault Zone (NAFZ) to the north. Within this complex and enigmatic framework, the Sandıklı Graben (10 km wide, 30 km long) has formed at the eastern continuation of the Western Anatolian extensional province at the north‐northwestward edge of the Isparta Angle. Recent studies have suggested that the horst–graben structures in West Anatolia formed in two distinct extensional phases. According to this model the first phase of extension commenced in the Early–Middle Miocene and the last, which is accepted as the onset of neotectonic regime, in Early Pliocene. However, it is controversial whether two‐phase extension was separated by a short period of erosion or compression during Late Miocene–Early Pliocene. Both field observations and kinematic analysis imply that the Sandıklı Graben has existed since the Late Pliocene, with biaxial extension on its margins which does not necessarily indicate rotation of regional stress distribution in time. Although the graben formed later in the neotectonic period, the commencement of extension in the area could be Early Pliocene (c. 5 Ma) following a severe but short time of erosion at the end of Late Miocene. The onset of the extensional regime might be due to the initiation of westward motion of Anatolian Platelet along the NAFZ that could be triggered by the higher rate of subduction at the east Aegean–Cyprus Arc in the south of the Aegean Sea. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
10.
《International Geology Review》2012,54(12):1557-1567
ABSTRACTThe present-day tectonic framework of Turkey comprises mainly two strike-slip fault systems, namely dextral North Anatolian and sinistral East Anatolian faults. They are considered as the main cause of deformation patterns in Anatolia. These two mega shear systems meet at Kargapazar? village of Karl?ova county. The area to the east of the junction has a transpressional tectonic regime between the Eurasian and Arabian plates and is characterized, based on field observation, by a network of faults defining a typical horsetail splay structure. The horsetail splay is interpreted as marking the termination of the North Anatolian Fault System (NAFS), which continues eastward into the Varto Fault Zone (VFZ) and then dies out. The present study reveals that the VFZ is made up of two main parts, namely the principal displacement zone (PDZ) and the transpressional splay zone (TPSZ), both characterized by the right-lateral strike-slip with reverse motion. However, the area to the east of Varto is characterized dominantly by reverse-thrust faults and E–W-trending faults as shown by focal mechanism solutions. The generation of the VFZ as a transpressional termination to the NAFS can be related directly to the block movements of the Eurasian, Anatolian, and Arabian plates. 相似文献
11.
Erdin Bozkurt 《Geodinamica Acta》2013,26(1-3):3-30
AbstractTurkey forms one of the most actively deforming regions in the world and has a long history of devastating earthquakes. The belter understanding of its neotectonic features and active tectonics would provide insight, not only for the country but also for the entire Eastern Mediterranean region. Active tectonics of Turkey is the manifestation of collisional intracontinental convergence- and tectonic escape-related deformation since the Early Pliocene (~5 Ma). Three major structures govern the neotectonics of Turkey; they are dextral North Anatolian Fault Zone (NAFZ), sinistral East Anatolian Fault Zone (EAFZ) and the Aegean–Cyprean Arc. Also, sinistral Dead Sea Fault Zone has an important role. The Anatolian wedge between the NAFZ and EAFZ moves westward away from the eastern Anatolia, the collision zone between the Arabian and the Eurasian plates. Ongoing deformation along, and mutual interaction among them has resulted in four distinct neotectonic provinces, namely the East Anatolian contractional, the North Anatolian, the Central Anatolian ‘Ova’ and the West Anatolian extensional provinces. Each province is characterized by its unique structural elements, and forms an excellent laboratory to study active strike-slip, normal and reverse faulting and the associated basin formation. © 2001 Éditions scientifiques et médicales Elsevier SAS 相似文献
12.
《International Geology Review》2012,54(9):818-829
The Southeast Anatolian orogen is a part of the eastern Mediterranean-Himalayan orogenic belt. Development of the Southeast Anatolian orogen began with the first ophiolite obduction onto the Arabian platform during the Late Cretaceous, and it continued until the Miocene. Its lingering effects continue to be discernible at present. During the Late Cretaceous-Miocene interval, three major deformational phases occurred, related to Late Cretaceous, Eocene, and Miocene nappe emplacements. The Miocene nappes are composed of ophiolites and metamorphic massifs. For a decade, field studies in the region have shown that strike-slip tectonics played a role complementary to the major horizontal effects of the nappe movement, as indicated by: (1) fault systems active during the Eocene; (2) different Eocene rock units composed of coeval continental and deep-sea deposits and presently tectonically juxtaposed; and (3) other stratigraphic and structural data obtained across the present strike-slip fault zones. These strike-slip faults possibly resulted from oblique subduction of the mid-oceanic ridge underneath the northerly situated Yuksekova ensimatic island-arc complex, causing a gradual cessation of the island-arc system. The subduction also led to the development of a back-arc pull-apart basin, i.e., the Maden basin, which opened on the upper plate. The geologic history in Southeast Anatolia resembles the development of the San Andreas fault system and subsequent tectonic evolution. 相似文献
13.
Various earthquake fault types, mechanism solutions, stress field, and other geophysical data were analyzed for study on the crust movement in the Tibetan plateau and its tectonic implications. The results show that numbers of thrust fault and strike-slip fault type earthquakes with strong compressive stress near NNE-SSW direction occurred in the edges around the plateau except the eastern boundary. Some normal faulting type earthquakes concentrate in the Central Tibetan plateau. The strikes of fault planes of thrust and strike-slip faulting earthquakes are almost in the E-W direction based on the analyses of the Wulff stereonet diagrams of fault plane solutions. This implies that the dislocation slip vectors of the thrust and strike-slip faulting type events have quite great components in the N-S direction. The compression motion mainly probably plays the tectonic active regime around the plateau edges. The compressive stress in N-S or NE-SW directions predominates earthquake occurrence in the thrust and strike-slip faulting event region around the plateau. The compressive motion around the Tibetan plateau edge is attributable to the northward motion of the Indian subcontinent plate. The northward motion of the Tibetan plateau shortened in the N-S direction encounters probably strong obstructions at the western and northern margins. 相似文献
14.
《International Geology Review》2012,54(8):701-713
Compressional or extensional troughs occupied by at least two sedimentary fills of dissimilar age, origin, facies, internal structure, and deformation pattern are herein termed superimposed basins. The lower and older fill of such basins is inherited from the latest compressional paleotectonic regime, and therefore is highly deformed (folded to thrust faulted). In contrast, the upper fill (neotectonic fill) is nearly flat, or undeformed, resting on the erosional surface of the lower fill with an angular unconformity. Superimposed basins occur mostly in or adjacent to recently active extensional terrains and recent strike-slip fault zones cutting across suture zones. Within the framework of neotectonics, recent geologic studies such as field geologic mapping, measured stratigraphic sections, aerial photography, and remote-sensing studies conducted in Turkey have shown that a number of well-developed and preserved superimposed basins occur along and adjacent to the North Anatolian transform fault (NATF), obliquely crossing the late Tertiary Izmir-Ankara-Erzincan suture zone (IAESZ). One such superimposed basin is the Refahiye, previously and erroneously interpreted to be a strike-slip basin of Pliocene age. In contrast, this study demonstrates that it is a well-preserved superimposed basin consisting of a combination of both an early-formed, early-middle Miocene piggy-back basin (the older Refahiye basin) and a newly developing strike-slip basin (the Kova basin). The Refahiye basin, located on the southern block of the Niksar-Erzincan segment of the Northern Anatolian fault master strand (NAFMS), contains two fills: (1) lower-middle Miocene latest paleotectonic fill (lower fill), and (2) Plio-Quaternary neotectonic fill (upper fill). The lower fill consists mostly of fluvial red clastics approximately 1 km thick with intercalations of gypsum lenses and shallow-marine reefal limestone of early-middle Miocene age. It is intensely folded, thrust-faulted, and not confined the present-day configuration of the Refahiye basin. The lower fill and its deformational structures, such as folds and thrust faults, are crossed and displaced dextrally by an active strike-slip fault system, the NATE In contrast, the upper fill, which rests on the erosional surface of the lower fill with an angular unconformity, consists of Plio-Quaternary terrace conglomerates, Quaternary imbricated gravels, and fine-grained Quaternary plain sediments (mostly silt and clay); these were deposited within a newly developing strike-slip basin—the Kova pull-apart basin—superimposed on the lower fill of the Refahiye basin. The upper fill is undeformed and nearly flat-lying. All these characteristics reveal that the present configuration of the Refahiye basin is a superimposed basin, herein termed the Refahiye superimposed basin. 相似文献
15.
J. Angelier B. Colletta J. Chorowicz L. Ortlieb C. Rangin 《Journal of Structural Geology》1981,3(4):347-357
A detailed field analysis of Neogene and Quaternary faults in Baja California has enabled us to reconstruct the stress pattern and the tectonic evolution of the central and southern parts of the peninsula. The deformation, which is related to the opening of the gulf, affects the whole peninsula, but decreases from east to west. Most observed faults, normal and/or dextral, strike NNW-SSE to WNW-ESE; their mechanisms include both strike-slip and dip-slip, as well as intermediate motions. Compressional events have occurred since Late Neogene times, but were probably of minor quantitative importance because reverse faults are rare and small.The principal fault pattern includes dextral NNW-SSE Riedel shears and N-S tension faults induced by dextral strike-slip along two main NW-SE fault zones bordering the peninsula: the Gulf of California to the east, which is the most important, and the Tosco-Abreojos fault to the west. The resulting pattern of deformation shows that the eastern part has been a complex transform-extensional zone since Late Miocene-Early Pliocene times. 相似文献
16.
The Isparta Angle (IA) is a reverse Λ-shaped morphotectonic structure located to the north of Antalya Gulf in the Eastern Mediterranean Sea. It resulted from the northward curvature of the originally E–W-trending Tauride orogenic belt owing to the nappe emplacements and related clockwise and anti-clockwise rotations in a time period of Early Paleocene to Early Pliocene. The IA is included in the southwest Anatolian tensional neotectonic domain and characterized by a series of grabens and horsts bounded by active normal faults of dissimilar length and trend. The evolutionary history of the graben-horst system is episodic. It is evidenced by two graben fills. These are older and modern (younger) graben fills separated by an intervening angular unconformity. The modern graben fill is nearly flat-lying (non-deformed) whereas older graben fill was deformed into a series of anticlines and synclines with ENE-trending curvi-linear axes by a short-term compressive tectonic regime operated in NNW–SSE direction during Late Pliocene. The diagnostic structures taking a part in the development of grabens and shaping the northern section of the IA are the margin-boundary normal faults. They occur in numerous single and several fault zones displaying a basin ward facing step-like land shape. Most of fault segments, particularly the master faults, are active and have a capacity of creating destructive earthquakes with a magnitude (up to Mw?=?7.0). This is evidenced by both the historical and instrumental period earthquakes. Both the focal mechanism solution of earthquakes and the stereographic plots of slip-plane data, measured on the active margin-boundary faults of various grabens comprising the IA, on the Schmidt lower hemisphere net obviously reveal that the IA is under the influence of the tensional neotectonic regime, not a compressive tectonic regime, i.e. the sinistral strike-slip shearing along the Pliny arc has not propagated yet onshore, and its commencement age is Early Quaternary. 相似文献
17.
《Journal of Asian Earth Sciences》1999,17(5-6):683-702
The Thakkhola–Mustang graben is located at the northern side of the Dhaulagiri and Annapurna ranges in North Central Nepal. The structural pattern is mainly characterised by the N020–040° Thakkhola Fault system responsible for the development of the half-graben. A detailed study of the substrate and the sedimentary fill in several outcrops indicates polyphased faulting:-pre-sedimentation faulting (Miocene), with a mainly NNW–SSE to N–S compressional stress expressed in the substratum by N020–040° and N180–N010° sinistral and N130–140° dextral conjugate strike-slip faults;-syn-sedimentation faulting (Pliocene–Pleistocene), characterised by a W–E to WNW–ESE extensional stress and tectonic subsidence of the half-graben during the Tetang period (Pliocene probably), followed by a doming of the Tetang deposits and a short period of erosion (cf. Pliocene planation surface and unconformity between the Tetang and Thakkhola Formations); the Thakkhola period (Pleistocene) is characterized by a W–E to WNW–ESE extensional stress and a major subsidence of the half graben;-post-sedimentation recurrent extensional faulting and N–S and NE–SW normal faults in the late Quaternary terrace formations.Geodynamic interpretation of the faulting is discussed in relation to the following:
- 1.the geographic situation of the Thakkhola–Mustang half-graben in the southern part of Tibet and its setting in the Tethyan series above the South Tibetan Detachment System (STDS);
- 2.the geodynamic conditions of the convergence between India and Eurasia and the dextral east–west shearing between the High Himalayas and south Tibet;
- 3.the possible relations between the sinistral Thakkhola and the dextral Karakorum strike-slip faults in a N–S compressional stress regime during the Miocene.
18.
Following final closure of the Neotethyan Ocean during the late Miocene, deformation in central Turkey has led to crustal thickening and uplift to produce the Anatolian Plateau followed by westward extrusion of terranes by strike–slip. Widespread volcanism has accompanied this latter (neotectonic) phase, and palaeomagnetic study of the volcanism shows a coherent record of differential block rotations, indicating that the Anatolian region is not a plate (or ‘platelet’) sensu stricto but is undergoing distributed internal deformation. To evaluate the scale of neotectonic rotations in the transition zone near the western limit of tectonic escape and the border of the extensional domain in central-west Turkey, we have studied the palaeomagnetism at 82 sites in volcanic suites distributed along a 140-km lineament with north–south trend and ranging in age from 18 to 8 Ma. Comparable deflection of magnetic remanence from the present field direction is identified along the full length of the lineament. A mean clockwise rotation of 12.3±4.2° is determined for this western sector of the Anatolian strike–slip province. Since similar rotations are observed in the youngest and oldest units, this cumulative rotation occurred after the late Miocene. When interpreted together with results elsewhere in Anatolia, it is inferred that the rotation is later than crustal thickening and uplift of the Anatolian Plateau and entirely a facet of the tectonic escape. Inclinations are mostly 10° shallower than the predicted Miocene field and are considered to reflect the presence of a persistent inclination anomaly in the Mediterranean region. Larger rotations departing from the regional trend are also observed within the study region, but are confined to the vicinity of major faults, notably those bounding the Afyon-Ak
ehir Graben.The pattern of neotectonic declinations across Anatolia identifies strong anticlockwise rotation in the east near the Arabian pincer with progressive reduction in the amount of rotation towards the west; it becomes zero or slightly clockwise at the western extremity of the accreted terrane collage. Rotations also appear to become generally younger towards the south. Crustal deformation has therefore been distributed, and the net effect of terrane extrusion to the west and south has been to expand the curvature of the Tauride Arc. The westward radial expansion of the extruded terranes is inferred to combine with backroll on the Hellenic Arc to produce the contemporary extensional province in western Turkey. 相似文献
19.
鸟山-古董山地区位于塔里木盆地西部, 巴楚隆起与麦盖提斜坡之间, 鸟山、玛南、玛扎塔格、古董山和罗斯塔格构造带在此交汇, 附近还发育与之密切相关的沙陇断裂, 十分引人注目。鸟山-古董山地区的主干断裂形成于晚白垩世, 包括鸟山、罗斯塔格和玛扎塔格晚白垩世冲断构造带和玛南晚白垩世走滑断裂带, 玛南断裂是玛扎塔格构造带与鸟山和罗斯塔格构造带之间的调节断层。该期构造变形受控于南羌塘和拉萨地块与亚洲大陆之间的碰撞造山作用。鸟山-古董山地区的断裂构造于中新世末基本定型。因帕米尔突刺楔入于塔里木和卡拉库姆之间, 在塔西南地区形成一系列走滑断裂, 包括玛扎塔格-罗斯塔格中新世末走滑断裂, 古董山断裂是其派生断层。晚白垩世是研究区构造和圈闭的关键形成期, 上新世晚期-全新世早期以古近系底部膏盐层为主滑脱面的滑脱-冲断构造保护早期形成的圈闭和油气藏。鸟山和玛扎塔格构造带是研究区最有利的油气勘探区带, 玛南构造带是重要的油气运移通道。 相似文献
20.
Jos Miguel Martínez-Martínez Guillermo Booth-Rea Jos Miguel Azan Federico Torcal 《Tectonophysics》2006,422(1-4):159-173
Pliocene and Quaternary tectonic structures mainly consisting of segmented northwest–southeast normal faults, and associated seismicity in the central Betics do not agree with the transpressive tectonic nature of the Africa–Eurasia plate boundary in the Ibero-Maghrebian region. Active extensional deformation here is heterogeneous, individual segmented normal faults being linked by relay ramps and transfer faults, including oblique-slip and both dextral and sinistral strike-slip faults. Normal faults extend the hanging wall of an extensional detachment that is the active segment of a complex system of successive WSW-directed extensional detachments which have thinned the Betic upper crust since middle Miocene. Two areas, which are connected by an active 40-km long dextral strike-slip transfer fault zone, concentrate present-day extension. Both the seismicity distribution and focal mechanisms agree with the position and regime of the observed faults. The activity of the transfer zone during middle Miocene to present implies a mode of extension which must have remained substantially the same over the entire period. Thus, the mechanisms driving extension should still be operating. Both the westward migration of the extensional loci and the high asymmetry of the extensional systems can be related to edge delamination below the south Iberian margin coupled with roll-back under the Alborán Sea; involving the asymmetric westward inflow of asthenospheric material under the margins. 相似文献