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>

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 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.

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>

Deformation of continental blocks within convergent plates: Anatolia as a case study

2020 ◽  
Author(s):  
Cengiz Zabcı ◽  
Taylan Sançar ◽  
Müge Yazıcı ◽  
Anke M. Friedrich ◽  
Naki Akçar
Keyword(s):  
Fault Zone ◽  
Plate Boundary ◽  
Slip Rate ◽  
Shear Zones ◽  
Strike Slip ◽  
Central Anatolia ◽  
Western Boundary ◽  
The West ◽  
Secondary Importance ◽  
Continental Block

<p>Anatolia is part of the west-central Alpide plate-boundary zone, particularly where the deformation is characterized by the westward extrusion of this continental block between the Arabian-Eurasian collision in the east and the Hellenic Subduction in the west. Although, this motion mostly happens along the boundary structures, i.e., the North Anatolian and East Anatolian shear zones, there are multiple studies documenting the active deformation along NE-striking sinistral and NW-striking dextral strike-slip faults within the central and eastern parts of Anatolia. These secondary faults slice Anatolia into several pieces giving formation of the Malatya-Erzincan, Cappadocian and Central Anatolian slices from east to west, where their boundary geometries are strongly controlled by the weak zones, the Tethyan Suture Zones.</p><p>We compiled all geological slip-rate and palaeoseismological studies, which point out inhomogeneous magnitude of deformation along different sections of these secondary structures. The Central Anatolian Fault Zone, the westernmost NE-striking sinistral strike-slip structure and the western boundary between the Central Anatolia and Cappadocian slices, has an average horizontal slip-rate of about 1 to 1.5 mm/a for the last few tens of thousands of years. The earthquake recurrence of about 4500 years between two events revealed on the northern sections of the CAFZ also support this rate of deformation. However, the Malatya-Ovacık Fault Zone has a bimodal behaviour in terms of deformation rate, which is 2.5 times higher along its northern member, the Ovacık Fault (OF) than the southern one, the Malatya Fault (MF) (2.5 to 1 mm/a), respectively. This velocity difference between two distinct members of the same fault zone can be explained by the relative westward motion of slices where the OF makes the direct contact between the Central Anatolian and Malatya-Erzincan, and the MF delimits Cappadocian and Malatya-Erzincan slices. Although these structures, which are shallow and probably deform only the upper crust, are of having secondary importance, yet they are still capable of producing infrequent but strong earthquakes within this highly deforming convergent setting. This study is supported by TÜBİTAK projects no. 114Y227 and 114Y580.</p>

Kinematic restoration of the southern North Atlantic and the Alpine Tethys during the Mesozoic

2020 ◽  
Author(s):  
Gianluca Frasca ◽  
Gianreto Manatschal ◽  
Patricia Cadenas Martínez
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Plate Boundary ◽  
Boundary Region ◽  
Plate Boundaries ◽  
European Alps ◽  
Variable Degree ◽  
Kinematic Evolution ◽  
Tethys Realm ◽  
Iberian Plate

<p>Continental rifting preceding stable seafloor spreading is characterized by a multistage evolution during lithosphere extension. Wide regions of exhumed mantle contain linear magnetic anomalies with a strongly debated nature and origin. Contrasting information used to set up dynamic plate models has resulted in a plethora of alternative interpretations. Structural and stratigraphic records at plate boundaries show indeed variable degree of discrepancies with what expected from computed plate motions during rifting stages. The definition of robust spatial and temporal kinematic constraints using combined offshore and onshore approaches represents a major challenge to unravel rifted margins evolution.   <br> <br>In this study, we address the problem outlined above using the Mesozoic southern North Atlantic and the Alpine Tethys, west and east of the Iberian plate, as a natural laboratory. The two systems are part of the same Africa-Europe kinematic framework and record distinctive Mesozoic rift events and a subsequent Tertiary compression. While in the southern North Atlantic the kinematic framework is still preserved, in the Alpine Tethys, subsequent subduction/collision erased the paleogeographic framework. The study area is among the best investigated but also most debated geological domains on the globe.</p><p>In our analysis we (1) integrate rift domains in plate kinematic models and re-consider the nature of the magnetic anomaly J in the southern N-Atlantic; (2) discuss the results of recent studies in the northern part of the Iberian plate; and (3) show new data from the Alpine Tethys realm (Central European Alps and Southern Apennines). We discuss the implications of these observations for the geometry of the rift systems developed around Iberia.</p><p>Our robust data network radically reduces the range of possible kinematic solutions. We reconstruct thus the position of Iberia and Adria relative to Europe and Africa and we evaluate the kinematic evolution and the width of the southern North Atlantic and the Alpine Tethys domains during the Mesozoic. The analysis emphasizes (1) the stepping geometry of the plate boundary for the Atlantic-Tethys interaction, (2) the strong partitioning of deformation in time and space, and (3) the large-scale pattern of coeval compression and extension along the Africa-Europe diffuse plate boundary region.</p>

scholarly journals The Rockall and the Orphan Basins of the Southern North Atlantic Ocean: Determining Continuous Basins across Conjugate Margins

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 178
Author(s):  
Heide MacMahon ◽  
J. Kim Welford ◽  
Larry Sandoval ◽  
Alexander L. Peace
Keyword(s):  
Atlantic Ocean ◽  
Early Cretaceous ◽  
North Atlantic ◽  
Driving Forces ◽  
North Atlantic Ocean ◽  
The West ◽  
The North ◽  
Plate Reconstructions ◽  
Conjugate Margins ◽  
Atlantic Margin

Reconstructions of the opening of the North Atlantic Ocean generally result in the Orphan Basin, offshore Newfoundland, Canada, lying approximately conjugate to the rift basins on the Irish Atlantic margin at the onset of seafloor spreading toward the end of the Early Cretaceous. Most of these plate reconstructions have involved rigid plates with plate motions based solely on the interpretation of oceanic magnetic anomalies. In particular, these reconstructions often show the Rockall Basin, west of Ireland, forming a continuous Mesozoic basin with the West Orphan Basin, offshore Newfoundland. However, more recent plate reconstructions involving deformable plates have called this conjugate relationship into question. The goal of this study is to investigate the validity of this potentially continuous basin system by reconstructing and restoring present-day seismically-constrained geological models both spatially and temporally back to their original configurations pre-rift. By comparing the reconstructions in terms of sedimentary package thicknesses and crustal thicknesses in 3D, using both rigid and deformable plate reconstructions to orient the reconstructed models, we are able to test different basin connectivity scenarios using a multidisciplinary approach. Our analysis provides subsurface geophysical support for the hypothesis that the Rockall Basin was originally conjugate to and continuous with the East Orphan Basin during Jurassic rifting, later linking to the West Orphan Basin as rifting evolved during the Early Cretaceous. This complex basin evolution example highlights the need for using 3D rifting mechanism models to properly understand the fundamental driving forces during rifting and has significant implications for assessing basin prospectivity across conjugate margin pairs.

scholarly journals The Combined Effects of SST and the North Atlantic Subtropical High-Pressure System on the Atlantic Basin Tropical Cyclone Interannual Variability

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 329
Author(s):  
Albenis Pérez-Alarcón ◽  
José C. Fernández-Alvarez ◽  
Rogert Sorí ◽  
Raquel Nieto ◽  
Luis Gimeno
Keyword(s):  
High Pressure ◽  
Interannual Variability ◽  
Central America ◽  
North Atlantic ◽  
The West ◽  
The Bahamas ◽  
Pressure System ◽  
North Atlantic Subtropical High ◽  
The North ◽  
The North Atlantic

The combined effect of the sea surface temperature (SST) and the North Atlantic subtropical high-pressure system (NASH) in the interannual variability of the genesis of tropical cyclones (TCs) and landfalling in the period 1980–2019 is explored in this study. The SST was extracted from the Centennial Time Scale dataset from the National Oceanic and Atmospheric Administration (NOAA), and TC records were obtained from the Atlantic Hurricane Database of the NOAA/National Hurricane Center. The genesis and landfalling regions were objectively clustered for this analysis. Seven regions of TC genesis and five for landfalling were identified. Intercluster differences were observed in the monthly frequency distribution and annual variability, both for genesis and landfalling. From the generalized least square multiple regression model, SST and NASH (intensity and position) covariates can explain 22.7% of the variance of the frequency of TC genesis, but it is only statistically significant (p < 0.1) for the NASH center latitude. The SST mostly modulates the frequency of TCs formed near the West African coast, and the NASH latitudinal variation affects those originated in the Lesser Antilles arc. For landfalling, both covariates explain 38.7% of the variance; however, significant differences are observed in the comparison between each region. With a statistical significance higher than 90%, SST and NASH explain 33.4% of the landfalling variability in the archipelago of the Bahamas and central–eastern region of Cuba. Besides, landfalls in the Gulf of Mexico and Central America seem to be modulated by SST. It was also found there was no statistically significant relationship between the frequency of genesis and landfalling with the NASH intensity. However, the NASH structure modulates the probability density of the TCs trajectory that make landfall once or several times in their lifetime. Thus, the NASH variability throughout a hurricane season affects the TCs trajectory in the North Atlantic basin. Moreover, we found that the landfalling frequency of TCs formed near the West Africa coast and the central North Atlantic is relatively low. Furthermore, the SST and NASH longitude center explains 31.6% (p < 0.05) of the variance of the landfalling intensity in the archipelago of the Bahamas, while the SST explains 26.4% (p < 0.05) in Central America. Furthermore, the 5-year moving average filter revealed decadal and multidecadal variability in both genesis and landfalling by region. Our findings confirm the complexity of the atmospheric processes involved in the TC genesis and landfalling.

Newly identified strike-slip plate boundary in the northeastern Arabian Sea

Geology ◽  
2000 ◽  
Vol 28 (4) ◽  
pp. 355 ◽  
Author(s):  
Nina Kukowski ◽  
Thies Schillhorn ◽  
Ernst R. Flueh ◽  
Katrin Huhn
Keyword(s):  
Arabian Sea ◽  
Plate Boundary ◽  
Strike Slip

Mesozoic Tectonic Setting of SE Sundaland After Magmatism and Suture Evidences in JS-1 Ridge Area

2021 ◽  
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Tectonic Setting ◽  
Plate Boundary ◽  
Early Jurassic ◽  
The South ◽  
Magmatic Arc ◽  
Plate Convergence ◽  
Ridge Area ◽  
Cretaceous Subduction

Mesozoic plate convergence in SE Sundaland has been a source of debate for decades. A determination of plate convergence boundaries and timing have been explained in many publications, but not all boundaries were associated with magmatism. Through integration of both plate configurations and magmatic deposits, the basement can be accurately characterized over time and areal extents. This paper will discuss Cretaceous subductions and magmatic arc trends in SE Sundaland area with additional evidence found in JS-1 Ridge. At least three subduction trends are captured during the Mesozoic in the study area: 1) Early Jurassic – Early Cretaceous trend of Meratus, 2) Early Cretaceous trend of Bantimala and 3) Late Cretaceous trend in the southernmost study area. The Early Jurassic – Early Cretaceous subduction occurred along the South and East boundary of Sundaland (SW Borneo terrane) and passes through the Meratus area. The Early Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo and Paternoster terranes) and pass through the Bantimala area. The Late Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo, Paternoster and SE Java – South Sulawesi terranes), but is slightly shifted to the South approaching the Oligocene – Recent subduction zone. Magmatic arc trends can also be generally grouped into three periods, with each period corresponds to the subduction processes at the time. The first magmatic arc (Early Jurassic – Early Cretaceous) is present in core of SW Borneo terrane and partly produces the Schwaner Magmatism. The second Cretaceous magmatic arc (Early Cretaceous) trend is present in the SW Borneo terrane but is slightly shifted southeastward It is responsible for magmatism in North Java offshore, northern JS-1 Ridge and Meratus areas. The third magmatic arc trend is formed by Late Cretaceous volcanic rocks in Luk Ulo, the southern JS-1 Ridge and the eastern Makassar Strait areas. These all occur during the same time within the Cretaceous magmatic arc. Though a mélange rock sample has not been found in JS-1 Ridge area, there is evidence of an accretionary prism in the area as evidenced by the geometry observed on a new 3D seismic dataset. Based on the structural trend of Meratus (NNE-SSW) coupled with the regional plate boundary understanding, this suggests that both Meratus & JS-1 Ridge are part of the same suture zone between SW Borneo and Paternoster terranes. The gradual age transition observed in the JS-1 Ridge area suggests a southward shift of the magmatic arc during Early Cretaceous to Late Cretaceous times.

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