Lithosphere tearing at STEP faults: response to edges of subduction zones

Govers, Rob; Wortel, M. J. R.

doi:10.1016/j.epsl.2005.03.022

Cited by 582 publications

(601 citation statements)

References 57 publications

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“…To the west, along a profile located at the longitude of 70°W, where the proposed tear would be older, the Moho topography is less pronounced than along profile 67°W. A possible explanation for these observations is that the Moho interface has gradually ''relaxed'' since 55 Ma along profiles 67°W and 70°W, as the tip of the tear/strike-slip system has moved to the east, confirming the predictions of the shear tear model [Clark et al, 2008b;Govers and Wortel, 2005]. …”

Section: San Sebastián Strike-slip Faultsupporting

confidence: 67%

“…One of the implications of this interpretation is the existence of a basal decollement located at middle or lower crustal depths where the strikeslip fault and the thrusts merge and above which the orogen ''floats'' [Oldow et al, 1990]. Alternatively the strike-slip system has been interpreted as the location of an eastward propagating lithospheric tear in the context of slab detachment in convergent-to-transform plate boundaries [Clark et al, 2008b;Govers and Wortel, 2005;Molnar and Sykes, 1969]. The occurrence of the dramatic change in crustal thickness observed along the 67°W velocity model at the San Sebastián -El Pilar fault shows that the strike-slip system is not a fault confined to the crust but that it enters the mantle, and is therefore a lithospheric-scale feature (Figure 12).…”

Section: San Sebastián Strike-slip Faultmentioning

confidence: 99%

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Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Magnani¹,

Zelt²,

Levander³

et al. 2009

J. Geophys. Res.

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[1] We present the results of new seismic reflection and wide-angle data across the SE Caribbean plate boundary. The 550 km long N-S profile crosses the structures involved in the active 55 Ma long continent-arc oblique collision between the Caribbean (CAR) and the South American (SA) plate. From the north to the south these structures include the accretionary prism, the extinct volcanic arc (Leeward Antilles arc), the Tertiary Bonaire basin, the continental-size dextral strike-slip fault system (San Sebastián-El Pilar fault), the allochthonous exhumed terranes, and the authocthonous fold and thrust belt (Caribbean Mountain system) and foreland basin. The wide-angle data show that these elements are characterized by different velocity structures and that they are separated by sharp lateral velocity variations. The Leeward Antilles arc exhibits a velocity structure similar to that of the Lesser Antilles active volcanic arc, indicating that the extinct arc has not been modified by the collision with the SA plate. The data show a $20 km change in crustal thickness across the San Sebastián fault, suggesting that the dextral strike-slip fault is a crustal feature that likely continues in the mantle as a primary strand of the plate boundary between the South American and the Caribbean plates. South of the strike-slip fault and beneath the exhumed eclogitic terranes, the data image a north dipping, high-velocity (>6.5 km/s) anomaly in the upper crust (3-11 km), indicating that high-pressure/low-temperature rocks are the likely lithologies responsible for the high seismic velocities and suggesting that exhumation of these assemblages is enabled by the strike-slip fault.

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Section: San Sebastián Strike-slip Faultsupporting

confidence: 67%

Section: San Sebastián Strike-slip Faultmentioning

confidence: 99%

Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Magnani¹,

Zelt²,

Levander³

et al. 2009

J. Geophys. Res.

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“…The tectonostratigraphy includes from top to bottom includes the high-pressure-low-temperature (HP-LT) metamorphic Tavşanlı zone [Okay, 1981[Okay, , 1984[Okay, , 1986Whitney, 2006, 2008;Whitney and Davis, 2006;Çetinkaplan et al, 2008] with cooling ages of ∼80 Ma Sherlock et al, 1999], underlain by greenschists and blueschists of Paleocene metamorphic age of the Afyon zone [Okay, 1984;Okay et al, 1996;Candan et al, 2005]. Both HP zones exhumed already in the Paleocene to Eocene, and were at, or close to the surface throughout most of the metamorphic history of the Menderes Massif [Özcan et al, 1988;Göncüoglu et al, 1992;Harris et al, 1994]. South of the Menderes Massif, the northern and lowermost part of the Lycian Nappes also experienced late Cretaceous to Paleocene HP metamorphism, possibly equivalent to the Afyon zone Rimmelé et al, 2003aRimmelé et al, , 2005Rimmelé et al, , 2006Candan et al, 2005], whereas the southern part of the Lycian Nappes experienced no metamorphism [Dumont et al, 1972;Bernoulli et al, 1974;Gutnic et al, 1979;Robertson, 1997, 1998].…”

Section: Hinsbergen Et Al: Exhumation With a Twist Tc3009 Tc3009mentioning

confidence: 99%

“…The database from both the metamorphic and nonmetamorphic domains of the Aegean and west Anatolian orogen is among the richest in the world, making the region instrumental to geologically calibrate geodynamic processes, linking, e.g., back-arc extension and exhumation to slab roll-back [Berckhemer, 1977;Le Pichon and Angelier, 1979;Meulenkamp et al, 1988;Jolivet and Faccenna, 2000;Jolivet, 2001], nappe stacking to subduction [Faccenna et al, 2003;van Hinsbergen et al, 2005avan Hinsbergen et al, , 2005cJolivet and Brun, 2010], exhumation of (ultra-) highpressure ((U)HP) metamorphic rocks to subduction channel 1 [Thomson et al, 1999;Jolivet et al, 2003;Ring et al, 2007Ring et al, , 2010 or back-arc evolution [Avigad et al, 1997;Ring and Layer, 2003], and dating and calibrating tectonic and volcanic responses to slab edge tectonics [Govers and Wortel, 2005;van Hinsbergen et al, 2007;Zachariasse et al, 2008;Dilek and Altunkaynak, 2009].…”

Section: Introductionmentioning

confidence: 99%

Exhumation with a twist: Paleomagnetic constraints on the evolution of the Menderes metamorphic core complex, western Turkey

et al. 2010

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Much remains to be understood about the links between regional vertical axis rotations, continental extension, and shortening. In western Turkey, Miocene vertical axis rotations have been reported that occur simultaneously with the extensional exhumation of the Menderes metamorphic core complex, which has been related to back‐arc extension in the eastern part of the Aegean back arc. In this paper we explore the spatial and temporal relationships between vertical axis rotations in southwestern Turkey and extensional unroofing of the Menderes Massif. To this end, we provide a large set of new paleomagnetic data from western Turkey, and integrate these with the regional structural evolution to test the causes and consequences of oroclinal bending in the Aegean region. The Lycian Nappes and Bey Dağları are shown to rotate ∼20° between 16 and 5 Ma, defining the eastern limb of the Aegean orocline. This occurred contemporaneously with the exhumation of the central Menderes Massif (along extensional detachments) and after the latest Oligocene to early Miocene exhumation of the northern and southern Menderes massifs. Exhumation of the latter two was not associated with vertical axis rotations. The lower Miocene volcanics in the region from Lesbos to Uşak, to the north of the central Menderes Massif underwent a small clockwise rotation, insignificant with respect to Eurasia. This shows that exhumation of the central Menderes Massif was associated with a vertical axis rotation difference between the northern and southern Menderes massifs of ∼25°–30°. This result is in excellent agreement with the angle defined by the trends of Büyük Menderes and Alaşehir detachments, as well as the angle defined by the regionally curving stretching lineation pattern across the central Menderes Massif. These structures define a pivot point (rotation pole) for the west Anatolian rotations. The rotation of the southern domain, including the southern Menderes Massif, the Lycian Nappes, and Bey Dağları, must have led to N–S contraction east of this pole. The eastern limit of the rotating domain is formed by the transpressional couple of the Aksu thrust and Kırkkavak Fault in the center of the Isparta angle. Previously reported clockwise rotations in the volcanic fields near Afyon may be the result of distributed N–S shortening east of the pivot point. The precise accommodation of this shortening history remains open for investigation. Late Oligocene to early Miocene extension in the eastern part of the Aegean back arc was NE–SW oriented and likely bounded by a discrete transform. This transform may be associated with an early evolution of the eastern Aegean subduction transform edge propagator fault. Oroclinal bending in the west Anatolian region is likely related to a reconnection of the eastern part of the Aegean orocline with the African northward moving plate in tandem with roll back in the Aegean back arc, comparable to a recently postulated scenario for western Greece.

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“…The northern and southern margins of the Sevier belt were almost certainly truncated by Subduction Transform Edge Propagator (STEP) faults (Govers and Wortel 2005) because the adjacent North American platform terrace to the north lacks Sevier-age deformation (Hildebrand 2013). The geology to the south is less well known but the thrust belt is Laramide in age so STEP faults are interpreted here to delineate the northern and southern margins of the promontory in the mid-mantle anomaly.…”

Section: Plate Trajectories and Paleomagnetismmentioning

confidence: 99%

Geology, Mantle Tomography, and Inclination Corrected Paleogeographic Trajectories Support Westward Subduction During Cretaceous Orogenesis in the North American Cordillera

Hildebrand

2014

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Geological evidence, including the presence of two passive margin platforms, juxtaposed and mismatched deformation between North America and more outboard terranes, as well as the lack of rift deposits, suggest that North America was the lower plate during both the Sevier and Laramide events and that subduction dipped westward beneath the Cordilleran Ribbon Continent (Rubia). Terranes within the composite ribbon continent, now present in the Canadian Cordillera, collided with western North America during the 125–105 Ma Sevier event and were transported northward during the ~80–58 Ma Laramide event, which affected the Cordillera from South America to Alaska. New high-resolution mantle tomography beneath North America reveals a huge slab wall that extends vertically for over 1000 km, marks the site of long-lived subduction, and provides independent verification of the westward-dipping subduction model. Other workers analyzed paleogeographic trajectories and concluded that the initial collision took place in Canada at about 160 Ma – a time and place for which there is no deformational thickening on the North American platform – and later farther west where subduction was not likely westward, but eastward. However, by utilizing a meridionally corrected North American paleogeographic trajectory, coupled with the geologically most reasonable location for the initial deformation, the position of western North America with respect to the relict superslab parsimoniously accounts for the timing and extents of both the Sevier and Laramide events. SOMMAIRELes indications géologiques, en particulier la présence de deux marges de plateforme passives, de déformations adjacentes non-conformes entre l’Amérique du Nord et les terranes extérieurs, ainsi que l’absence de gisements de rift, permet de croire que l’Amérique du Nord était la plaque sous-jacente durant les événements de Sevier et de Laramide et que la subduction plongeait vers l’ouest sous le continent rubané de la Cordillères (Rubia). Les terranes du continent rubané composite, maintenant au sein de la Cordillère canadienne, sont entrés en collision avec l’ouest de l’Amérique du Nord durant l’événement Sevier (125-105 Ma), et ont été transportés vers le nord durant l’événement Laramide (~80–58 Ma), laquelle a affecté la Cordillère, de l’Amérique du Sud à l’Alaska. Une nouvelle tomographie haute résolution du manteau sous l’Amérique du Nord montre la présence d’un gigantesque mur de plaques vertical qui s’étend sur 1 000 km, marque le site d’une subduction de longue haleine, et offre une validation indépendante du modèle d’une subduction à pendage vers l’ouest. D’autres chercheurs ont analysé les trajectoires paléogéographiques et conclu que la collision initiale s’est produite au Canada vers 160 Ma – un moment et un endroit sans épaississement par déformation sur la plateforme d’Amérique du Nord – et plus tard plus à l’ouest, là où la subduction n’était vraisemblablement pas vers l’ouest, mais vers l’est. Cela dit, en considérant une trajectoire paléogéographique de l’Amérique du Nord corrigée longitudinalement, avec la position géologique la plus probable de la déformation initiale, la position de la portion ouest de l’Amérique du Nord par rapport aux restes de la super-plaque explique alors facilement la chronologie et l’étendue des épisodes Sevier et Laramide.

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Lithosphere tearing at STEP faults: response to edges of subduction zones

Cited by 582 publications

References 57 publications

Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Exhumation with a twist: Paleomagnetic constraints on the evolution of the Menderes metamorphic core complex, western Turkey

Geology, Mantle Tomography, and Inclination Corrected Paleogeographic Trajectories Support Westward Subduction During Cretaceous Orogenesis in the North American Cordillera

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