Paleoseismic and morphometric manifestation of the transition between the Western Anatolian extensional regime and the North Anatolian Fault strike-slip zone

2020 ◽  
Author(s):  
Volkan Karabacak ◽  
Taylan Sançar ◽  
Yusuf Büyükdeniz
Keyword(s):  
Strike Slip ◽  
North Anatolian Fault ◽  
Slip Zone ◽  
Asymmetry Factor ◽  
The West ◽  
Southern Boundary ◽  
Geological Evidence ◽  
The North ◽  
Morphometric Analyses ◽  
Eastern Segment

<p>The strike-slip dominated North Anatolian Fault Zone (NAFZ) prolongs to the west and furcates into several branches where shear is distributed to multiple parallel/subparallel segments. The earlier structures that resulted from the ongoing Western Anatolian extension had a key role in the fact that the western part of the NAFZ has a wider deformation zone. Although the southern boundary of this zone is controversial, it is proposed that there is a strong interaction between the deformation zones of the NAFZ and Western Anatolian Extensional Province (WAEP) along the northern margin of the Uludag Range. Since this pivotal region marks the transition between the extensional regime and continental strike-slip zone, it is necessary to increase knowledge thereof. Within this ongoing study, we focused on the morphotectonic and paleoseismologic properties of the Ulubat and Bursa faults that delimits the northern boundary of the Uludag Range. The results of the morphometric analyses (topographic symmetry factor, asymmetry factor, hypsometric curve and integral, channel concavity, and integral analyses) that performed on 79 drainage basin to the south of these faults suggested that the vertical motion in the northeastern part of the Uludag Range changes abruptly to strike-slip dominated deformation, along with Ulubat Fault, towards the west of the Bursa basin.</p><p>The 50 km length, dextral Ulubat Fault was mapped in the field by using offset physiographic features and geological evidence. We divided the ENE–WSW striking Ulubat Fault into three segments that present the releasing double-bend geometry. There are two major changes in trends up to 20 degrees between each segment. The western segment has a length of 17 km in the E-W direction. The middle segment extends toward NE with a length of 20 km. The eastern segment stretches eastward for 13 km with a southward arc-shape geometry. We conducted the first paleoseismological trench studies on middle and eastern segments of the Ulubat Fault and identified at least 6 paleoearthquakes for the last 16 ka on both segments. The paleoseismic behavioral results which are consistent with the geometric segmentation show individual ruptures on each segment. Dated surface ruptures history show that the fault has used the same single trace in Holocene and the last events occurred in 1143 AD and 170 AD along the middle and eastern segments respectively.</p><p>Although further studies are needed to evaluate the paleoseismic recurrence interval, our results show that the Ulubat Fault takes over a considerable activity in the north of Uludag Range. The field evidence and morphometric analyses around the Uludag Range sign out that the Ulubat Fault forms the southernmost member of the NAFZ strike-slip domain. The eastern segment of the dextral Ulubat Fault has vertical component while the Bursa Fault exhibits the characteristics of the WAEP towards further east. This research was supported by the Disaster & Emergency Management Authority of Turkey (UDAP project; G-18-01).</p>

scholarly journals A reconstruction of Iberia accounting for W-Tethys/N-Atlantic kinematics since the late Permian-Triassic

2020 ◽  
Author(s):  
Paul Angrand ◽  
Frédéric Mouthereau ◽  
Emmanuel Masini ◽  
Riccardo Asti
Keyword(s):  
Plate Boundary ◽  
Strike Slip ◽  
Late Permian ◽  
Seismic Profiles ◽  
The West ◽  
Geological Evidence ◽  
The North ◽  
Kinematic Evolution ◽  
Well Data ◽  
Strike Slip Movement

Abstract. The West European kinematic evolution results from the opening of the West Neotethys and the Atlantic oceans since the late Paleozoic and the Mesozoic. Geological evidence shows that the Iberian domain well preserved the propagation of these two rift systems and is therefore key to significantly advance our understanding of the regional plate reconstructions. The Late Permian-Triassic tectonic evolution of Iberian rift basins shows that they have accommodated significant extension, but this tectonic stage is often neglected in most plate kinematic models, leading to the overestimation of the movements between Iberia and Europe during the subsequent Mesozoic (Early Cretaceous) rift phase. By compiling existing seismic profiles and geological constraints along the North Atlantic margins, including well data over Iberia, as well as recently published kinematic and paleogeographic reconstructions we propose a coherent kinematics model of Iberia that considers both the Neotethyan and Atlantic evolutions. Our model shows that the Europe-Iberia plate boundary was a domain of distributed and oblique extension made of two rift systems, in the Pyrenees and in the Iberian intra-continental basins. It differs from standard models that consider left-lateral strike-slip movement localized only in the northern Pyrenees in introducing a significant strike-slip movement south of Ebro accounting for Late Permian-Triassic extension and by emphasizing the need for an Ebro microcontinent. At a larger scale it emphasizes the role played by the late Permian-Triassic rift and magmatism, as well as strike-slip faulting in the evolution of the western Neotethyan Ocean and their control on localization of the Atlantic rift.

scholarly journals Basin Progress – Active Deformation Analysis by Tectonostratigraphic Elements and Geophysical Methods on North Anatolian Fault System (Eastern Marmara Region, Turkey)

2021 ◽  
Author(s):  
Bülent Doğan ◽  
Metin Aşcı ◽  
Ahmet Karakaş ◽  
Ertan Pekşen ◽  
Arzu Erener ◽  
...  
Keyword(s):  
Strike Slip ◽  
North Anatolian Fault ◽  
Fault System ◽  
Magnetic Method ◽  
Lake Basin ◽  
Active Deformation ◽  
Southern Boundary ◽  
The North ◽  
Dextral Strike Slip ◽  
Northern Branch

Abstract The Northern Branch of the North Anatolian Fault System controls and deforms the Izmit Basin and the Sapanca Lake Basin in the study area. Unlike the Sapanca Lake Basin, the oblique normal faults with WNW–ESE trending with maximum length of 5 km in the south of the basin have contributed to the deformation process in the formation of Izmit Basin. The fault sets mainly incline to the north. The N-S width of the dextral strike-slip active deformation was determined as 9 km at Izmit basin and 3.8 km at Sapanca Lake basin. Further, the minimum principal stress axes (σ3) vary in the trending ranges of N11°-74° E, which are caused by the transtensional stresses associated with strike-slip faulting in the Izmit Basin by a different tectonic source than the Sapanca Lake Basin. Besides, the crust depth of main strand of NAFS-NB was determined up to 1112 m by magnetic method. The secondary faults were determined by both magnetic and resistivity methods up to a depth of 110 m. The depression area between Izmit bay and Sapanca Lake on the northern Anatolian fault is an integrated basin with two dextral strike-slip tectonic origins. Thus, the Izmit Basin, along with the main strike-slip faulting, has been developed in the asymmetric negative flower structure, where only the southern boundary has become a fault. The Sapanca Lake Basin is a lazy-Z-shaped pull-apart system formed by the E–W trending fault as a releasing bend. A simple shear deformation ellipsoid with a long axis of approximately 35 km on the Northern Branch of the North Anatolian Fault System is defined for the Izmit – Sapanca integrated basin. Therefore, intra-basin deposits have different depths estimated from the gravity data in the Izmit – Sapanca integrated basin, and the maximum sediment thickness estimated is 2200 m in the middle of the Izmit Basin.

Unrest in the Magic Valley

2015 ◽  
Author(s):  
Chad Broughton
Keyword(s):  
San Antonio ◽  
Rio Grande ◽  
Farm Workers ◽  
The West ◽  
United Farm Workers ◽  
Southern Boundary ◽  
Border City ◽  
The North ◽  
Slow Moving ◽  
The Voice

One Evening in May 1967, in the parched border city of Mission, Texas, Ed Krueger had worked into the early evening on a painting and was late to the demonstration at the railroad crossing. He arrived there at 8:45 p.m. with his wife, Tina; his 18-year-old son, David; and Doug Adair, a young journalist writing for the magazine El Malcriado: The Voice of the Farm Worker. Just a few union members and bystanders were at the crossing when they arrived. Krueger, 36, a lanky and clean-cut minister, had been working with Local 2 of the United Farm Workers Organizing Committee (UFW) and had expected to see thirty or forty striking farmworkers and activists protesting the “scab melons” passing by on the next train. But they weren’t there, and Krueger was worried. They parked 75 feet south of the railroad crossing, on the west side of Conway Street. Krueger and his wife grabbed some hamburgers and sodas and leaned on their bumper to eat with their son. Adair went to talk to a reporter on the north side of the crossing. Joining Krueger was Magdaleno Dimas, an itinerant 29-year-old farmworker. A Mexico-born U.S. citizen, Dimas had a dragon tattoo on his right arm, a rose on his left, and an edgy zeal for the strike. They were waiting for a freight train carrying tens of thousands of recently harvested cantaloupes and honeydews loaded into thirty or so refrigerated cars. The melons had just been cut at La Casita ranch in Rio Grande City, thirty miles west of Mission. After a switch down-valley in Harlingen, the ranch’s melons would head north to San Antonio. La Casita, owned by a California company, operated nearly year round and employed 300 to 500 laborers on 2,700 acres of melons, peppers, carrots, cabbage, celery, and lettuce. The southern boundary of its well-ordered fruit and vegetable fields was the snaking Rio Grande River. All that separated La Casita from Mexico was a short swim across the slow-moving, greenish river that irrigated its fields.

Neotectonics of the SW Marmara region, NW Anatolia, Turkey

2006 ◽  
Vol 143 (2) ◽  
pp. 229-241 ◽  
Author(s):  
ÖMER FEYZI GÜRER ◽  
ERCAN SANGU ◽  
MUZAFFER ÖZBURAN
Keyword(s):  
Fault Zone ◽  
Structural Characteristics ◽  
Strike Slip ◽  
North Anatolian Fault ◽  
Marmara Region ◽  
Field Observations ◽  
Extensional Tectonics ◽  
North Anatolian Fault Zone ◽  
The North ◽  
Differential Movement

This study reports on the geometric and structural characteristics of the North Anatolian Fault Zone in the southwest Marmara region. The geometric and kinematic features of the faults in the region are described, based on field observations. In addition, the Neogene and Quaternary basin fill which occupies large areas in the region has been determined, and the tectonic regimes controlling these basins are explained. The neotectonic regime is also explained considering different deformation phases affecting the region. The N–S extension and E–W strike-slip have affected the region possibly since the latest Pliocene–Quaternary. Field observations show that these extensional tectonics around the south Marmara region are related to right strike-slip on the E–W North Anatolian fault zone and the N–S Aegean extensional system. The faults in this zone trend approximately E–W in the eastern part of the region and NE–SW towards the west of the region, indicating that they accommodate rotation in addition to differential movement between adjacent blocks.

scholarly journals A reconstruction of Iberia accounting for Western Tethys–North Atlantic kinematics since the late-Permian–Triassic

Solid Earth ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 1313-1332 ◽  
Author(s):  
Paul Angrand ◽  
Frédéric Mouthereau ◽  
Emmanuel Masini ◽  
Riccardo Asti
Keyword(s):  
North Atlantic ◽  
Kinematic Model ◽  
Plate Boundary ◽  
Strike Slip ◽  
Late Permian ◽  
Geological Evidence ◽  
Western Tethys ◽  
The North ◽  
Kinematic Evolution ◽  
Strike Slip Movement

Abstract. The western European kinematic evolution results from the opening of the western Neotethys and the Atlantic oceans since the late Paleozoic and the Mesozoic. Geological evidence shows that the Iberian domain recorded the propagation of these two oceanic systems well and is therefore a key to significantly advancing our understanding of the regional plate reconstructions. The late-Permian–Triassic Iberian rift basins have accommodated extension, but this tectonic stage is often neglected in most plate kinematic models, leading to the overestimation of the movements between Iberia and Europe during the subsequent Mesozoic (Early Cretaceous) rift phase. By compiling existing seismic profiles and geological constraints along the North Atlantic margins, including well data over Iberia, as well as recently published kinematic and paleogeographic reconstructions, we propose a coherent kinematic model of Iberia that accounts for both the Neotethyan and Atlantic evolutions. Our model shows that the Europe–Iberia plate boundary was a domain of distributed and oblique extension made of two rift systems in the Pyrenees and in the Iberian intra-continental basins. It differs from standard models that consider left-lateral strike-slip movement localized only in the northern Pyrenees in introducing a significant strike-slip movement south of the Ebro block. At a larger scale it emphasizes the role played by the late-Permian–Triassic rift and magmatism, as well as strike-slip faulting in the evolution of the western Neotethys Ocean and their control on the development of the Atlantic rift.

scholarly journals Origin and age of the Shenshan tectonic mélange in the Jiangshan-Shaoxing-Pingxiang Fault and late Early Paleozoic juxtaposition of the Yangtze Block and the West Cathaysia terrane, South China

2021 ◽  
Author(s):  
Lijun Wang ◽  
Kexin Zhang ◽  
Shoufa Lin ◽  
Weihong He ◽  
Leiming Yin
Keyword(s):  
South China ◽  
Strike Slip ◽  
Carbonaceous Shale ◽  
Early Paleozoic ◽  
Yangtze Block ◽  
The West ◽  
Northern Margin ◽  
The North ◽  
Tectonic Mélange ◽  
Different Parts

When and how the Yangtze Block (Yangtze) and the West Cathaysia terrane (West Cathaysia) in South China were amalgamated are critical to a better understanding of the Neoproterozoic to early Paleozoic tectonic evolution of South China and remain highly debatable. A key to this debate is the tectonic significance of the Jiangshan-Shaoxing-Pingxiang (JSP) Fault, the boundary between Yangtze and West Cathaysia. The Shenshan mélange along the JSP Fault has the typical block-in-matrix structure and is composed of numerous shear zone-bounded slivers/lenses of rocks of different types and ages that formed in different tectonic environments, including middle to late Tonian volcanic and volcanogenic sedimentary rocks (turbidite) of arc/back-arc affinity, a series of middle Tonian ultramafic to mafic plutonic rocks of oceanic island basalt affinity, a carbonaceous shale that was deposited in a deep marine environment, and a red mudstone. U-Pb zircon ages and acritarch assemblages (Leiosphaeridia-Brocholaminaria association) found in the turbidite confirm its Tonian age, and fossils from the carbonaceous shale (Asteridium-Comasphaeridium and Skiagia-Celtiberium-Leiofusa) constrains its age to the Early to Middle Cambrian. Field relationships and available age data leave no doubt that the ultramafic-mafic rocks are exotic blocks (rather than intrusions) in the younger metasedimentary rocks. We conclude that the Shenshan mélange is not an ophiolitic mélange, but rather a tectonic mélange that formed as a result of movement along the JSP Fault in the early Paleozoic. We suggest that Yangtze and West Cathaysia were two separate microcontinents, were accreted to two different parts of the northern margin of Gondwana in the early Early Paleozoic, and juxtaposed in the late Early Paleozoic through strike-slip movement along the JSP Fault. We further suggest that the ca. 820 Ma collision in the Jiangnan Orogen took place between Yangtze and a (micro)continent that is now partly preserved as the Huaiyu terrane and was not related to West Cathaysia. We compare our model for South China with the accretion of terranes in the North American Cordillera and propose a similar model for the relationship between the Avalon and Meguma terranes in the Canadian Appalachians, i.e., the two terranes were accreted to two different parts of the Laurentian margin and were later juxtaposed through margin-parallel strike slip faulting.

A reconstruction of Iberia accounting for West Tethys/North Atlantic kinematics since the Late Permian-Triassic

2020 ◽  
Author(s):  
Paul Angrand ◽  
Frédéric Mouthereau ◽  
Emmanuel Masini ◽  
Riccardo Asti
Keyword(s):  
Early Cretaceous ◽  
North Atlantic ◽  
Plate Boundary ◽  
Strike Slip ◽  
Significant Advance ◽  
Late Permian ◽  
The West ◽  
Geological Evidence ◽  
Kinematic Evolution ◽  
Strike Slip Movement

<p>The West European kinematic evolution results from the opening the West Neo-Tethys and the Atlantic oceans since the Late Paleozoic and the Mesozoic, respectively. Geological evidence suggests that the Iberian domain was strongly overprinted by the propagation of these two rift systems and is therefore key to significantly advance our understanding of the regional plate reconstructions. The Late Permian-Triassic tectonic evolution of Iberian rift basins show that they have accommodated a significant component of extension, which remain however difficult to quantify. This tectonic stage is therefore often neglected in most plate kinematic models, leading to the overestimation of the movements between Iberia and Europe during the subsequent Mesozoic (Early Cretaceous) rift phase.</p><p>We compile seismic profiles and geological constraints along the North Atlantic margins and over Iberia, as well as existing kinematic and paleogeographic reconstructions to build a coherent, global kinematics model that consider both the Neo-Tethyan and Atlantic evolutions. We use tectonic subsidence analyses from the literature to quantify the apparent extension during the Late Permian to Early Cretaceous extensive phase. We show that an improved knowledge of the distribution in space and time of the deformation between Europe and the Iberian domain can be obtained for the Late Permian-Mid Cretaceous period. Our model differs from standard models that consider left-lateral strike-slip movement localized in the northern Pyrenees. The Europe-Iberia plate boundary rather forms a domain of distributed and oblique extension made of two rift systems, in the Pyrenees and in the Iberian intra-continental basins. This reconstruction emphasizes the need for an Ebro block and the significant strike-slip movement south of the Ebro block that is however minimized by accounting for the previous Late Permian-Triassic extension. We propose that these two rifts accommodated the same order of magnitude of strike-slip movement during the evolution of the Iberia-Europe (diffuse) plate boundary.</p><p>Our reconstructions reveal that the Late Permian-Triassic rift and magmatic evolution of the western Europe, at the western tip of the Neo-Tethyan Ocean, controlled the subsequent localization of the Atlantic rift. Our study provides a significant advance that allows reconciling the main geological observations, including the lack of major strike-slip faulting and a large oceanic basin in northern Iberia. The temporal overlap between Late Variscan magmatism and the Neo-Tethyan extension is not directly addressed in this contribution but its impact on the Earth’s surface evolution and topography during initial rifting certainly requires further investigations.</p>

Geological evidence for the last two faulting events on the north Anatolian Fault zone in the Mudurnu Valley, western Turkey

1991 ◽  
Vol 193 (4) ◽  
pp. 335-345 ◽  
Author(s):  
Yasutaka Ikeda ◽  
Yasuhiro Suzuki ◽  
Erdal Herece ◽  
Fuat Şaroǧlu ◽  
Ahmet M. Isikara ◽  
...  
Keyword(s):  
Fault Zone ◽  
North Anatolian Fault ◽  
North Anatolian Fault Zone ◽  
Western Turkey ◽  
Geological Evidence ◽  
The North

scholarly journals When did the North Anatolian fault reach southern Marmara, Turkey?

Geology ◽  
2021 ◽  
Author(s):  
Volkan Karabacak ◽  
Taylan Sançar ◽  
Gökhan Yildirim ◽  
I. Tonguç Uysal
Keyword(s):  
Shear Zones ◽  
Strike Slip ◽  
North Anatolian Fault ◽  
Plate Boundaries ◽  
Marmara Region ◽  
Plate Motions ◽  
The North ◽  
Southern Branch ◽  
Timing Of Initiation ◽  
Northern Branch

We dated syntectonic calcites on fault planes from the southern branch of the western North Anatolian fault (NAF) in northern Turkey using U-Th geochronology. We selected strike-slip faults that are kinematically related to the current regional strain field. The isotopic ages cluster around different periods during the past ~700 k.y. The most prominent cluster peak of 510.5 ± 9.5 ka (1σ) is consistent with the maximum cumulative strike-slip offset data and tectonic plate motions measured by GPS data, highlighting the fact that the present configuration of the NAF in the southern Marmara region started at ca. 500 ka or earlier. These new isotopic ages, combined with previous considerations of regional tectonics, reveal that faulting along the western NAF initiated primarily in the southern Marmara region at least a few hundred thousand years earlier than the timing suggested for the northern branch of the western NAF. This study presents an innovative approach to constrain the timing of initiation of currently active fault segments along the NAF in southern Marmara. U-Th geochronology of fault-hosted calcite thus has a wide application in determining absolute ages of fault episodes in wider shear zones along plate boundaries.

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