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1.
C. Kurtuluş B. Doğan F. Sertçelik M. Canbay H. M. Küçük 《Marine Geophysical Researches》2009,30(2):121-134
The Edremit Gulf, which developed during the Neogene-Quaternary, is a seismically active graben in NW Anatolia (Turkey) surrounded
by the Sakarya continent. The sedimentary deposits in the gulf overlie the bedrock unconformably and can be separated into
two parts as upper and lower deposits based on similarity of their seismic characteristics, and because the contact between
them is clear. The lower deposits are characterized in the seismic profiles by the absence of well defined, continuous reflectors
and are strongly disturbed by faults. A tectonic map and structural model of the Edremit Gulf was derived from interpreting
21 deep seismic profiles trending NE–SW and NW–SE within the gulf. Two fault systems were distinguished on the basis of this
compilation. The NNW–SSE trending parallel faults are low-angle normal faults formed after compression. They controlled and
deformed the lower basin deposits. A syncline and anticline with a broad fold-curvature length resulted in folds that developed
parallel to basin boundaries in the lower basin deposits. The ENE–WSW trending high-angle faults have controlled and deformed
the northern basin of the Edremit Gulf. The folds developed within the northern lower deposits originated from the listric
geometry of the faults. These faults are normal faults associated with regional N–S extension in western Anatolia. The Edremit
Gulf began to open under the control of low-angle NNW–SSE trending faults that developed after the compression of western
Anatolia in an E–W direction in the early Neogene. Subsequently, regional N–S extensional stress and high-angle normal faults
cut the previous structures, opened the northern basin, and controlled and deformed the lower basin deposits in the gulf.
As a result, the Edremit Gulf has not been controlled by any strike-slip faults or the Northern Anatolian Fault. The basin
developed in the two different tectonic regimes of western Anatolia as an Aegean type cross-graben from the Neogene to Holocene. 相似文献
2.
Multiphase rifts tend to produce fault populations that evolve by the formation of new faults and reactivation of earlier faults. The resulting fault patterns tend to be complex and difficult to decipher. In this work we use seismic reflection data to examine the evolution of a normal fault network in the Oseberg Fault Block in the northern North Sea Rift System – a rift system that experienced Permian – Early Triassic and Middle Jurassic – Early Cretaceous rifting and exhibits N-S, NW-SE and NE-SW oriented faults.Both N-S- and NW-SE-striking faults were established during the Permian – Early Triassic rifting, as indicated by Triassic growth packages in their hanging walls. In contrast, the NE-SW-striking faults are younger, as they show no evidence of Permian – Early Triassic growth, and offset several N-S- and NW-SE-striking faults. Structural analysis show that a new population of NW-SE-striking faults formed in the Lower – Middle Jurassic (inter-rift period) together with reactivation of N-S-striking Permian – Early Triassic faults, indicating a NE-SW inter-rift extension direction.During the Middle Jurassic – Early Cretaceous rifting, faults of all orientations (N-S, NW-SE and NE-SW) were active. However, faults initiated during the Middle Jurassic – Early Cretaceous rifting show mainly N-S orientation, indicating E-W extension during this phase. These observations suggest a reorientation of the stress field from E-W during the Permian – Early Triassic rift phase to NE-SW during inter-rift fault growth and back to E-W during the Middle Jurassic – Early Cretaceous rift phase in the Oseberg area. Hence, the current study demonstrates that rift activity between established rift phases can locally develop faults with new orientations that add to the geometric and kinematic complexity of the final fault population. 相似文献
3.
对琼东南盆地陆架区晚中新世以来的断层活动性进行研究, 有助于理解南海西北部晚中新世以来的构造演化, 也对该区钻井平台的安全性评估、海洋工程勘查以及区域稳定性评价等有重要意义。研究区断层走向主要为NWW向, 多数断层在晚中新世时期停止活动。通过对断层几何形态的统计分析以及使用高分辨率断层落差图法(T-Z图示法)对断层活动性进行量化分析, 结果显示: 断层活动性在晚中新世末期(5.5Ma)发生转变; 研究区南部的断层落差值大于北部; 南部断层停止活动的时间较北部断层稍晚。这些研究成果表明, 晚中新世末期研究区断层受构造应力变化的影响, 在生长发育过程中断层活动性质发生了改变, 由逆断层转为正断层。红河断裂带对琼东南盆地的构造演化起着重要的控制作用, 文章推测研究区断层活动性变化是由红河断裂带的构造反转所导致, 因为红河断裂带在5.5Ma时发生了走滑运动的反转, 与研究区的断层活动性变化在时间和性质上相耦合。 相似文献
4.
Bone Gulf is one of the inter-arm basins of the unusual K-shaped island of Sulawesi. Its age, character and origin are disputed. This study is based on recently acquired 2D seismic lines, seabed multibeam mapping and limited well data, and is linked to stratigraphy on land. The gulf is probably underlain by pre-Neogene volcanogenic, sedimentary, metamorphic and ultramafic rocks, and includes crust of Australian origin. We favour basin initiation in the Miocene rather than Eocene, by extension associated with strike-slip deformation. The main basin trends N–S and is divided into several sub-basins and highs. The highs segment the gulf and their WNW–ESE orientations reflect pre-Neogene basement structures. They are interpreted as strike-slip fault zones active at different times in the Neogene. A southern high was active relatively early, whereas further north there is evidence of young displacements during the Late Neogene. These are visible on the seabed above a high linked to the Kolaka Fault on land. Early basin-bounding faults are oriented NNW–SSE and record extension and strike-slip movements, like the sub-parallel Walanae Fault of South Sulawesi which can be traced offshore into extensional faults bounding the young and narrow Selayar Trough. Sediment in the basins came mainly from the north with contributions from both west and east. Carbonate deposits formed at the margins while deeper marine sediments were deposited in the axial parts of the gulf. An Early Pliocene unconformity can be mapped across the study area marking major uplift of Sulawesi and subsidence of Bone Gulf. This regional event caused major influx of clastic sediments from the north, development of a southward-flowing canyon system, and back-stepping and drowning of carbonates at the basin margins. Hydrocarbons are indicated by seeps, and Bone Gulf has potential sources, reservoirs and seals, but the complex faulting history is a risk. 相似文献
5.
渤海的地质演化与断裂活动 总被引：3，自引：0，他引：3
李延成 《海洋地质与第四纪地质》1993,13(2):25-34
本文将渤海的地质演化分为:前中生代、中生代和新生代三大时期,并论述各个时期的构造特征和地层分布。渤海的断裂系统主要有北北东—北东、近东西和北西向三组,每组断裂既有其各自的发生、发展规率,同时彼此之间又有一定的关联。 相似文献
6.
The Fingerdjupet Subbasin in the southwestern Barents Sea sits in a key tectonic location between deep rifts in the west and more stable platform areas in the east. Its evolution is characterized by extensional reactivation of N-S and NNE-SSW faults with an older history of Late Permian and likely Carboniferous activity superimposed on Caledonian fabrics. Reactivations in the listric NNE-SSW Terningen Fault Complex accommodated a semi-regional rollover structure where the Fingerdjupet Subbasin developed in the hangingwall. In parallel, the Randi Fault Set developed from outer-arc extension and collapse of the rollover anticline.N-S to NNE-SSW faults and the presence of other fault trends indicate changes in the stress regime relating to tectonic activity in the North Atlantic and Arctic regions. A latest Triassic to Middle Jurassic extensional faulting event with E-W striking faults is linked to activity in the Hammerfest Basin. Cessation of extensional tectonics before the Late Jurassic in the Fingerdjupet Subbasin, however, suggests rifting became localized to the Hammerfest Basin. The Late Jurassic was a period of tectonic quiescence in the Fingerdjupet Subbasin before latest Jurassic to Hauterivian extensional faulting, which reactivated N-S and NNE-SSW faults. Barremian SE-prograding clinoforms filled the relief generated during this event before reaching the Bjarmeland Platform. High-angle NW-prograding clinoforms on the western Bjarmeland Platform are linked to Early Barremian uplift of the Loppa High. The Terningen Fault Complex and Randi Fault Set were again reactivated in the Aptian along with other major fault complexes in the SW Barents Sea, leading to subaerial exposure of local highs. This activity ceased by early Albian. Post-upper Albian strata were removed by late Cenozoic uplift and erosion, but later tectonic activity has both reactivated E-W and N-S/NNE-SSW faults and also established a NW-SE trend. 相似文献
7.
The response of benthic foraminifera and ostracoda to heavy metal pollution in Gulf of Izmir (Eastern Aegean Sea) 总被引：1，自引：0，他引：1
F. Bergin F. Kucuksezgin E. Uluturhan I.F. Barut E. Meric N. Avsar A. Nazik 《Estuarine, Coastal and Shelf Science》2006,66(3-4):368-386
Benthic foraminifera can be used as environmental bioindicators, especially in polluted environments where their sensitivity to pollutants may be expressed by a modification in the assemblage. Nineteen sediment samples were collected in November 2002 from surficial sediments of the Gulf of Izmir (Turkey). The Gulf of Izmir is located in Western Turkey and surrounded by a densely populated community. The gulf has been contaminated by numerous heavy metals, but geochemical analyses have shown that metals are significant pollutants only in the inner part of the gulf. Outer and Middle Sections showed low levels of heavy metals, except the estuary of Gediz River. Eight heavy metals have been analyzed in all the sampling points. Sixty-seven foraminifer and 22 ostracod species were identified in 16 sediment samples. Statistical analysis shows that there is a significant correlation between foraminifera species and heavy metals. The most polluted Inner Sections are dominated by the tolerant species Ammonia tepida that may be used as pollution indicator. The gradient observed in heavy metal concentrations between the Outer and Inner Sections has a prevalent influence on the foraminiferal distribution. There is a gradient of the number of species, increasing from the Inner Section toward the Outer Section. The occurrence of test abnormalities among foraminifera may represent a useful biomarker for evaluating long-term environmental impacts in a coastal region. 相似文献
8.
We studied the active deformation zone of the middle strand of the North Anatolian Fault Zone through the southern part of
the Sea of Marmara by means of high-resolution as well as deep seismic reflection data. Our main objective was to investigate
the active deformation within the uppermost sedimentary layers at high resolution as well as deeper sedimentary layers, focusing
on the tectonic and stratigraphic setting between Gemlik and Bandırma. The middle strand of the North Anatolian Fault reaching
the Gulf of Gemlik is a main fault which has a lazy-S shape in the Gulf of Gemlik, and extends westwards to Bandırma as a
main fault which is an E–W-trending single right-lateral fault controlling the zone along the Gemlik and Bandırma sub-basins.
Small-scale faults, consistent with a dextral shear regime, are present in the vicinity of the main fault. Several oblique
fault groups parallel to the main fault were detected. The deformation in the Gulf of Gemlik is characterized by a series
of synthetic and antithetic faults emanating from the main fault. The boundary faults in the Gulf of Gemlik have a compressive
component, which indicates the sill areas of the gulfs of Gemlik and Bandırma to be push-up structures. Four seismic stratigraphic
units were identified in the sediments of the gulfs of Gemlik and Bandırma, providing evidence of tectonic influence. The
present tectonic structure between Gemlik and Bandırma is not a pull-apart structure. The microseismic study in this area
has shown that fault planes are either strike-slip or compressional, and that the stress tensor is compatible with pure strike-slip
in the E–W fault system. 相似文献
9.
Çağatay M. N. Görür N. Alpar B. Saatçılar R. Akkök R. Sakınç M. Yüce H. Yaltırak C. Kuşcu I. 《Geo-Marine Letters》1998,18(1):1-9
The Gulf of Saros is an Upper Miocene transtensional basin in NW Anatolia, formed by the interaction between the North Anatolian
Fault and the N-S extensional tectonic régime of the Aegean. The present configuration of the basin evolved mainly during
the Plio-Quaternary under the increased activity of the North Anatolian Fault. During the late Miocene-late Quaternary, no
sedimentation took place on the shelves. After this long hiatus, an important change in tectonic style about 0.2 Ma BP allowed
sedimentation to resume in the gulf.
Received: 14 February 1997 / Revision received: 12 November 1997 相似文献
10.
珠江三角洲的活动断裂主要为弱活动断裂,分别属于NW,NE和EW向三组断裂,活动断裂是控制该三角洲断块运动和地震活动的关键。珠江三角洲主要为区域稳定性中等地区。 相似文献
11.
Neslihan Ocako?lu 《Geo-Marine Letters》2012,32(1):17-28
New (2009) multi-beam bathymetric and previously published seismic reflection data from the NE-SW-oriented Fethiye Bay and
the neighboring N-S-oriented Marmaris Bay off SW Anatolia were evaluated in order to interpret the seafloor morphology in
terms of the currently still active regional tectonic setting. This area lies between the Pliny Trench, which constitutes
the eastern sector of the subduction zone between the African and Eurasian plates in the Eastern Mediterranean, and the Fethiye-Burdur
Fault Zone of the Anatolian Plate. The bathymetric data document the very narrow shelf of the Anatolian coast, a submarine
plain between the island of Rhodes and Marmaris Bay, and a large canyon connecting the abyssal floor of the Rhodes Basin with
Fethiye Bay. The latter are here referred to as the Marmaris Plain and Fethiye Canyon, respectively. Several active and inactive
faults have been identified. Inactive faults (faults f1) delineate a buried basin beneath the Marmaris Plain, here referred
to as the Marmaris Basin. Other faults that affect all stratigraphic units are interpreted as being active. Of these, the
NE-SW-oriented Marmaris Fault Zone located on the Marmaris Plain is interpreted as a transtensional fault zone in the seismic
and bathymetric data. The transtensional character of this fault zone and associated normal faults (faults f3) on the Marmaris
Plain correlates well with the Fethiye-Burdur Fault Zone on land. Another important fault zone (f4) occurs along the Fethiye
Canyon, forming the northeastern extension of the Pliny Trench. The transpressional character of faults f4 inferred from the
seismic data is well correlated with the compressional structures along the Pliny Trench in the Rhodes Basin and its vicinity.
These observations suggest that the Marmaris Fault Zone and faults f3 have evolved independently of faults f4. The evidence
for this missing link between the Pliny Trench and the Fethiye-Burdur Fault Zone implies possible kinematic problems in this
tectonic zone that deserve further detailed studies. Notably, several active channels and submarine landslides interpreted
as having been triggered by ongoing faulting attest to substantial present-day sediment transport from the coast into the
Rhodes Basin. 相似文献
12.
Recently acquired (2005) multi-beam bathymetric and high-resolution seismic reflection data from the E–W-oriented Gulf of Gökova off SW Anatolia were evaluated in order to assess the uneven seafloor morphology and its evolution in terms of present-day active regional tectonics. Stratigraphically, the three identified seismic units, i.e., the basement, deltaic sediments deposited during Quaternary glacial periods, and modern gulf deposits, are consistent with those observed in previous studies. Structurally, the folds and faults with strike-slip and reverse components have been regionally mapped for the first time. Of these, NE–SW-oriented left-lateral strike-slip faults with compressional components forming the so-called Gökova Fault Zone intersect and displace two WNW–ESE-oriented submarine ridges and deep submarine plains. Thus, strike-slip faults are the youngest major structures in the gulf, and control present-day active tectonism. E–W-oriented folds on the inner and outer shelf, which are generally accompanied by reverse faults, delimit the margins of these submarine ridges, and deform the young basin deposits. These features also reveal the concomitant existence of a compressional tectonic regime. The compressional structures probably represent pressure ridges along left-lateral strike-slip fault segments. However, some E–W-oriented normal faults occur on the northwestern and partly also southern shelf, and along the borders of the adjacent deep submarine plains. They are intersected and displaced by the strike-slip faults. The lower seismicity along the normal faults relative to the NE–SW-oriented strike-slip faults suggests that the former are at present inactive or at least less active. 相似文献
13.
渤海海域晚更新世—全新世的活动构造 总被引：2，自引：0，他引：2
利用在渤海最新获得的约5 000 km的浅层地震资料,发现在渤海海域发育大量晚更新世—全新世断裂和褶皱,进而对其分布、浅层结构、运动学性质和活动性进行了研究,绘制了渤海海域活动断裂分布图。研究结果表明:渤海晚更新世—全新世活动断裂主要走向为北北东向、北西向和近东西向,东西向断裂数量最多;断裂的形成受区域应力场和早期断裂的控制,而褶皱则以背斜居多,通常沿早期断裂带发育;就分布密度而言,辽东湾内断裂密度远小于其他海域,而同一构造单元其边界部位断裂密度大于单元内部;具继承性发展的断裂多具有复杂的破裂结构,破裂带剖面上呈耙形或"Y"字型,晚更新世沉积层变形明显;受断裂错动地层的形成时代表明,多数断裂的最新活动发生在晚更新世中期-晚期,部分断裂在全新世发生过活动;多数断裂具有明显正断拉张作用,而郯庐断裂带和张家口-蓬莱断裂带内次级断裂还可能具走向滑移分量;渤海浅层断裂的活动性与现代地震震中的分布具有较好的相关性,这对于渤海地震危险性评价具有重要意义。 相似文献
14.
Erdal Dolu Erkan Gökaşan Engin Meriç Mustafa Ergin Tolga Görüm Hüseyin Tur Berkan Ecevitoğlu Niyazi Avşar Muhittin Görmüş Fatmagül Batuk Buğser Tok Oktay Çetin 《Geo-Marine Letters》2007,27(6):355-381
The Quaternary evolution of the Gulf of İzmit, situated on the tectonically active North Anatolian Fault Zone (NAFZ), was
investigated using seismic reflection, paleontologic, and sediment textural data. On the basis of seismic stratigraphic and
sedimentologic-paleontologic interpretations, four depositional units were distinguished within the Plio-Quaternary sequence
of the Gulf of İzmit. According to these data, Plio-Quaternary deposits supplied from the northern terrestrial area started
to accumulate during a progradational phase, in a south-facing half-graben. A coarse-grained sedimentary unit prograding into
the gulf from the south since 200 ka b.p. indicates a dramatic variation in the evolution of the gulf, with the initiation of a new strike-slip fault of the NAFZ
and a corresponding uplift of the Armutlu Peninsula in the south of the gulf. During the evolution of this fault from a wide
shear zone consisting of right-stepped strike-slip faults and pull-apart basins to a localized principal fault zone, sediments
were deposited under the influence of northerly prograding terrestrial and shallow-marine conditions due to relative sea-level
fluctuations in the Marmara Sea. During this period, the Gulf of İzmit was invaded mainly by Mediterranean and partly by Black
Sea waters. In the latest glacial period, shallow areas in the gulf became subaerially exposed, whereas the central and western
sub-basins of the gulf turned into lakes. The present evolution of the Gulf of İzmit is controlled by the after effects of
the new rupture of the NAFZ and the estuarine nature of the gulf environment. 相似文献
15.
The NW-SE striking Otway Basin in southeastern Australia is part of the continental rift system that formed during the separation of Australia from Antarctica. The development of this sedimentary basin occurred in two phases of Late Jurassic-Early Cretaceous and Late Cretaceous rifting. The evolution of this basin is mainly associated with extensional processes that took place in a pre-existing basement of Archean, Proterozoic to Paleozoic age. In this study, the total amounts of extension and stretching factor (β factor) have been measured for six transects across the entire passive margin of the Otway Basin region. The results show significant variation in extensional stretching along the basin, with the smallest stretching factors in the easternmost (β = 1.73, 1.9) and westernmost part of the basin (β = 2.09), and the largest stretching factors in the central part (β = 2.14 to 2.44). The domain with the lowest β factor is underlain mostly by thicker lithosphere of the Delamerian Orogen and older crustal fragments of the Selwyn Block. In contrast, the region with the largest β factor and amount of extension is related to younger and thinner lithosphere of the Lachlan Orogen. The main basement structures have been mapped throughout eastern South Australia and Victoria to examine the possible relationships between the younger pattern of extensional faults and the older basement fabrics. The pattern of normal faults varies considerably along onshore and offshore components of the Otway Basin from west to east. It appears that the orientation of pre-existing structures in the basement has some control on the geometry of the younger normal faults across the Otway Basin, but only in a limited number of places. In most areas the basement fabric has no control on the younger faulting pattern. Basement structure such as the north-south Coorong Shear Zone seems to affect the geometry of normal faults by changing their strike from E-W to NW-SE and also, in the easternmost part of the basin, the Bambra Fault changes the strike of normal faults from NW-SE to the NE-SW. Our results imply that the properties of the continental lithosphere exert a major influence on the β factor and amount of crustal extension but only a minor influence on the geometry of extensional faults. 相似文献
16.
Erkan Gökaşan Cem Gazioğlu Bedri Alpar Zeki Yücel Şükrü Ersoy Oğuz Gündoğdu Cenk Yaltırak Buser Tok 《Geo-Marine Letters》2001,21(4):183-199
Active faults aligning in NW–SE direction and forming flower structures of strike-slip faults were observed in shallow seismic data from the shelf offshore of Avc?lar in the northern Marmara Sea. By following the parallel drainage pattern and scarps, these faults were traced as NW–SE-directed lineaments in the morphology of the northern onshore sector of the Marmara Sea (eastern Thrace Peninsula). Right-lateral displacements in two watersheds of drainage and on the coast of the Marmara Sea and Black Sea are associated with these lineaments. This right-lateral displacement along the course of these faults suggests a new, active strike-slip fault zone located at the NW extension of the northern boundary fault of the Ç?narc?k Basin in the Marmara Sea. This new fault zone is interpreted as the NW extension of the northern branch of the North Anatolian Fault Zone (NAFZ), extending from the Ç?narc?k Basin of the Marmara Sea to the Black Sea coast of the Thrace Peninsula, and passing through B üy ük çekmece and K ü ç ük çekmece lagoons. These data suggest that the rupture of the 17 August 1999 earthquake in the NAFZ may have extended through Avc?lar. Indeed, Avc?lar and ?zmit, both located on the Marmara Sea coast along the rupture route, were strongly struck by the earthquake whereas the settlements between Avc?lar and ?zmit were much less affected. Therefore, this interpretation can explain the extraordinary damage in Avc?lar, based on the newly discovered rupture of the NAFZ in the Marmara Sea. However, this suggestion needs to be confirmed by further seismological studies. 相似文献
17.
张家口-蓬莱断裂带渤海段晚第四纪活动特征 总被引：7，自引：0，他引：7
张家口-蓬莱断裂带是华北地区一条显著的地震带.利用最新获得的高分辨率浅层地震资料研究了渤海海域内该断裂带晚第四纪以来的活动特征.研究表明:在渤海,张家口-蓬莱断裂带主要由沙西断裂、埕北断裂、沙南断裂、沙东北断裂、柏各庄断裂、石臼坨3号断裂、渤中2号断裂和BZ29断裂等一系列NW走向断裂组成,走向在290°～310°之间;在浅层沉积物中各断裂由多条次级小断裂组成;晚第四纪以来主要表现出强烈的垂向运动特征,具有正断性质;海域各断裂的最新活动时代为晚更新世(Q3)末期-全新世(Q4)初期,并具有相同的活动趋势,在20 ka B.P.和60 ka B.P.左右活动强烈,统计计算显示平均垂向活动速率分别为0.15 mm/a和0.1 mm/a,近20 000 a以来的垂向活动速率超过0.06 mm/a. 相似文献
18.
Multichannel seismic reflection and multi-beam bathymetry data were used to study the active tectonic and syn-tectonic stratigraphic setting of the Gulf of ?zmit in the Marmara Sea (Turkey). The gulf and its near surroundings are deformed by the northern strand of the dextral North Anatolian Fault. Three connected basins of the gulf, the western (Dar?ca), central (Karamürsel) and eastern (Gölcük) basins are formed by active faults, as observed in the stacked and migrated seismic sections, as well as the bathymetry map. The main branch and its surrounding sedimentary strata are confined by normal faults to the north and south. These normal faults converge at depth towards the main fault, forming a negative flower structure in the gulf. The average maximum sedimentation rate is 0.4 mm/year according to the three most recent seismo-stratigraphic units that are located to the south of the main fault branch within the central basin. A 20° south-dipping major discontinuity along the northern shoreline of the gulf represents the top of Paleozoic basement. 相似文献
19.
In this paper, we demonstrate the effectiveness of steerable filters as a method of delineating the boundaries of subsurface geological structures. Steerable filters, generally used for edge detection on 2-D images, have the properties of band pass filters with certain directions and are applied to many image processing problems. We first tested the method on synthetic data and then applied it to the aeromagnetic data of İskenderun Basin and adjacent areas.İskenderun Basin is located in the Northeastern Mediterranean where African–Arabian and Anatolian plates are actively interacting. The basin fill records a complex tectonic evolution since the Early Miocene, involving ophiolite emplacement, diachronous collision of Eurasian and Arabian plates and subsequent tectonic escape related structures and associated basin formation. Geophysical investigations of the tectonic framework of İskenderun Basin of Turkey provide important insights on the regional tectonics of the Eastern Mediterranean and Middle East. In this study we show geological structures, which are responsible for the magnetic anomalies in İskenderun Basin and enlighten the structural setting of the Northeastern Mediterranean triple junction using steerable filters. We obtained a magnetic anomaly map of the region from the General Directorate of Mineral Research and Exploration as raw data and then evaluated this by steerable filters. We determined the magnetic anomaly boundaries for İskenderun Basin by using various types of steerable filters and correlated these to drilling data and seismic profiles from the Turkish Petroleum Corporation. The result of the steerable filter analysis was a clarified aeromagnetic anomaly map of İskenderun Basin. The tectonic structure of İskenderun Basin is divided into regions by an N–S trending oblique-slip fault defined by the steerable filter outputs. We propose a new tectonic structure model of İskenderun Basin and modify the direction of the East Anatolian Fault Zone. In our model, East Anatolian Fault Zone cross-cuts the basin as a narrow fault zone and continues towards the Cyprus arc. 相似文献
20.
The right-lateral Blanco Transform Fault Zone (BTFZ) offsets the Gorda and the Juan de Fuca Ridges along a 350 km long complex zone of ridges and right-stepping depressions. The overall geometry of the BTFZ is similar to several other oceanic transform fault zones located along the East Pacific Rise (e.g., Siquieros) and to divergent wrench faults on continents; i.e., long strike-slip master faults offset by extensional basins. These depressions have formed over the past 5 Ma as the result of continual reorientation of the BTFZ in response to changes in plate motion. The central depression (Cascadia Depression) is flanked by symmetrically distributed, inward-facing back-tilted fault blocks. It is probably a short seafloor spreading center that has been operating since about 5 Ma, when a southward propagating rift failed to kill the last remnant of a ridge segment. The Gorda Depression on the eastern end of the BTFZ may have initially formed as the result of a similar occurrence involving a northward propagating rift on the Gorda ridge system. Several of the smaller basins (East Blanco, Surveyor and Gorda) morphologically appear to be oceanic analogues of continental pull-apart basins. This would imply diffuse extension rather than the discrete neovolcanic zone associated with a typical seafloor spreading center. The basins along the western half of the BTFZ have probably formed within the last few hundred thousands years, possibly as the result of a minor change in the Juan de Fuca/Pacific relative motion. 相似文献