Future accreted terranes: a compilation of island arcs, oceanic plateaus, submarine ridges, seamounts, and continental fragments

Tetreault, J. L.; Buiter, Susanne

doi:10.5194/se-5-1243-2014

Cited by 62 publications

(35 citation statements)

References 286 publications

(321 reference statements)

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“…Continental basement is identified at ~ 5 s two‐way‐traveltime [ Mahanjane , ] suggesting a depth of ~6–7 km. Our inverse gravity model indicates an average crustal thickness of 19 km for the Beira High, which is consistent with it being either a continental fragment or an oceanic plateau [ Tetreault and Buiter , ]. Unfortunately, the only seismic refraction data collected over the Beira High could not provide velocities of its lower crust without ambiguity due to a sparse ray coverage [ Mueller et al ., ].…”

Section: Discussionsupporting

confidence: 59%

Reconstruction of the East Africa and Antarctica continental margins

et al. 2016

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The Early Jurassic separation of Antarctica from Africa plays an important role in our understanding of the dispersal of Gondwana and Pangea. Previous reconstruction models contain overlaps and gaps in the restored margins that reflect difficulties in accurately delineating the continent‐ocean‐boundary (COB) and determining the amount and distribution of extended continental crust. This study focuses on the evolution of the African margin adjacent to the Mozambique Basin and the conjugate Antarctic margin near the Riiser‐Larsen Sea. Satellite‐derived gravity data have been used to trace the orientations and landward limits of fracture zones. A 3‐D gravity inversion has produced a crustal thickness model that reliably quantifies the extent and amount of stretched crust. Crustal thicknesses together with fracture zone terminations reveal COBs that are significantly closer to the African and Antarctic coasts than previously recognized. Correlation of fracture zone azimuths and identified COBs suggests Antarctica began drifting away from Africa at approximately 171 Ma in a roughly SSE direction. An areal‐balancing method has been used to restore the crust to a uniform prerift thickness so as to perform a nonrigid reconstruction for both nonvolcanic and volcanic margins. Both margins reveal a trend of increasing extension from east to west. Our results suggest Africa underwent extension of 60–120 km, while Antarctic crust was stretched by 105–180 km. Various models tested to determine the direction of extension during rifting suggest that Antarctica moved away from Africa in a WNW‐ESE direction during the period between 184 and 171 Ma prior to the onset of seafloor spreading.

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Section: Discussionsupporting

confidence: 59%

Reconstruction of the East Africa and Antarctica continental margins

et al. 2016

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“…The oceanic crust density is varied from the classical value for a wet gabbro composition in the pressure-temperature conditions prevailing at the surface (2920 kg.m −3 Bousquet et al, 1997;Tetreault and Buiter, 2014). Crust density in the blueschist facies reaches 3160 kg.m −3 , but we try even higher densities, by imposing the mantle value, that would correspond to crust eclogitization and the heaviest crust, to maximize the column weight within the older plate (OP) in order to promote its 30 gravitational instability ( Fig.…”

Section: Crust and Tf Densitiesmentioning

confidence: 99%

Can subduction initiation at a transform fault be spontaneous?

Arcay¹,

Lallemand²,

Abecassis³

et al. 2019

Preprint

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Abstract. We propose a new exploration of the concept of spontaneous subduction, i.e., lithospheric gravitational collapse without any external forcing, at a transform fault (TF). We first seek candidates in recent subduction initiations at a TF that could fulfill the criteria of spontaneous subduction and retain 3 natural cases: Izu-Bonin-Mariana (IBM), Yap, and Matthew & Hunter. We next perform an extensive exploration of conditions allowing spontaneous gravitational sinking of the older plate in a oceanic TF using 2D thermo-mechanical simulations. Our parametric study aims at better deliminating the ranges of mechanical properties necessary to achieve the old plate sinking (OPS). The explored parameter set includes: crust and TF densities, brittle and ductile rheologies, and width of the weakened region around the TF. We focus on characterising OPS conditions in terms on (1) reasonable vs unrealistic values of mechanical parameters and (2) comparison to modern cases of subduction initiation in a TF setting. When modelled, OPS initiates following one of two distinct modes, depending mainly on the thickness of the overlying younger plate (YP). Asthenosphere may rise up to the surface above the sinking old plate provided that the YP remains motionless (verified for ages ≥ 5 Myr, mode 1). For lower YP ages (typically ≤ 2 Myr), the YP is dragged towards the OP resulting in a double-sided subduction (mode 2). When triggered, spontaneous OPS is extremely fast. The basic parameters to simulate OPS are the brittle properties of the shallow part of the lithosphere, controlling the plate resistance to bending, the distance away from the TF over which weakening is expected, and crust density. We find that all mechanical parameters have to be assigned extreme values to achieve OPS, that we consider as irrelevant. Furthermore, we point out inconsistencies between the processes and consequences of lithospheric instability as modelled in our experiments and geological observations of subduction infancy for the 3 natural candidates of subduction initiation by spontaneous OPS. We conclude that spontaneous instability of the thick OP at a TF evolving into mature subduction is an unlikely process of subduction initiation at modern Earth conditions.

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“…Clift and Vannucchi () indicated an average rate of tectonic erosion of 1 km/m.y. since 23 Ma for SW Mexico, which is high enough to have caused removal of the remnants of an accreted intraoceanic arc of average thickness (approximately 26 km; Tetreault & Buiter, ) during the Neogene.…”

Section: Northern Central America: a Collage Of Continental And Oceanmentioning

confidence: 99%

“…(1) Nonsteady subduction erosion can affect intraoceanic arcs in two ways: (a) tectonic erosion during the lifespan of an intraoceanic arc, with the removal of tens of kilometers of forearc crust (e.g., Azuero/Golfito Arc in Costa Rica, Buchs et al, ; Talkeetna Arc in Alaska, Clift et al, ; European Variscides, Oncken, ) and (b) tectonic erosion of an intraoceanic arc once it is accreted to a convergent margin (Clift et al, ). (2) Intraoceanic arcs may be underplated or subducted during arc‐arc collision events (Hall & Wilson, ; Tetreault & Buiter, , ; Yamamoto et al, ). (3) Chemical and mechanical weathering of igneous rocks, especially in tropical climates, may impede the study of intraoceanic arc records (Hall & Smyth, ; Hastie et al, ).…”

Section: Introductionmentioning

confidence: 99%

Sedimentary Record of Arc‐Continent Collision Along Mesozoic SW North America (Siuna Belt, Nicaragua)

et al. 2019

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The western margin of the Caribbean Plate is a typical example where oceanic and continental terranes have amalgamated by subduction, collision, and strike-slip processes. The boundaries between these blocks, as well as their tectonostratigraphic records, are generally covered by younger deposits and dense tropical vegetation, which may hamper reconstructing the accretionary evolution of the convergent margin. In that context, the study of overlap sedimentary assemblages represents an important tool to constrain the accretion timing of terranes. In northern Central America, the geology of the suture zone between the Chortis Block and the exotic Siuna Intraoceanic Arc indicates that the two terranes were assembled together during a Hauterivian arc-continent collision (approximately 134-131 Ma). The exotic origin of the intraoceanic arc is based on the nature of metamorphic blocks within and the kinematics of the Siuna Serpentinite Mélange. The short duration of the collision event is suggested by coeval exhumation of the Siuna Serpentinite Mélange and Chortis-derived coarse sedimentation (El Amparo Formation) along the suture zone, rapidly followed by onset of pelagic sedimentation (Rio Matis Formation). Although the collision appears to have been short lived and preserved only in the suture zone, postcollisional extension affected intra-arc to back-arc settings of the Chortis Block and led to the formation of kilometer-thick extensional basins. We envisage that the convergent margin inboard of SW Mexico-represented by the fringing Guerrero Intraoceanic Arc and the Mixteca continental terrane-underwent similar postcollisional extension, whereas the western margin of the proto-Caribbean oceanic realm experienced onset of WSW dipping subduction beneath the accreted Siuna Intraoceanic Arc.

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Future accreted terranes: a compilation of island arcs, oceanic plateaus, submarine ridges, seamounts, and continental fragments

Cited by 62 publications

References 286 publications

Reconstruction of the East Africa and Antarctica continental margins

Reconstruction of the East Africa and Antarctica continental margins

Can subduction initiation at a transform fault be spontaneous?

Sedimentary Record of Arc‐Continent Collision Along Mesozoic SW North America (Siuna Belt, Nicaragua)

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