Dynamic Evolution of Induced Subduction Through the Inversion of Spreading Ridges

Qing, Jiarong; Liao, Jie; Li, Lun; Gao, Rui

doi:10.1029/2020jb020965

Cited by 14 publications

(23 citation statements)

References 53 publications

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“…This behaviour is tied to low convergence rates, i.e., below 0.9 cm yr-1 (Figure 8B). Similar results have been obtained by Gülcher et al (2019) and Qing et al (2021), who observed in their numerical models, reactivation of multiple detachment faults upon their inversion but did not produce intra-oceanic subduction. When deformation does not localized in oceanic domain, the vertical rheological decoupling at the margin allows for the development of a long-lasting shear zone where stresses are relaxed through the formation of a decollement that propagate through the mantle.…”

Section: Favourable Conditions For Subduction Initiation At Passive Marginssupporting

confidence: 89%

“…Our results predict that even young (5 Myr old) oceanic lithospheres can support tectonic stress of up to 12 TN/m underlining its long-term stability. As such, subduction initiation along spreading ridges is largely favored by warm ridge and fast convergence rate (Figure 8C, see also Qing et al, 2021) and/or the implementation of lithosphere-scale pre-existing weak zones (Maffione et al, 2015) to localize deformation in the mantle lithosphere.…”

Section: Favourable Conditions For Subduction Initiation At Passive Marginsmentioning

confidence: 99%

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Kinematic Boundary Conditions Favouring Subduction Initiation at Passive Margins Over Subduction at Mid-oceanic Ridges

2021

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We perform numerical modelling to simulate the shortening of an oceanic basin and the adjacent continental margins in order to discuss the relationship between compressional stresses acting on the lithosphere and the time dependent strength of the mid-oceanic ridges within the frame of subduction initiation. We focus on the role of stress regulating mechanisms by testing the stress–strain-rate response to convergence rate, and the thermo-tectonic age of oceanic and continental lithospheres. We find that, upon compression, subduction initiation at passive margin is favoured for thermally thin (Palaeozoic or younger) continental lithospheres (<160 km) over cratons (>180 km), and for oceanic basins younger than 60 Myr (after rifting). The results also highlight the importance of convergence rate that controls stress distribution and magnitudes in the oceanic lithosphere. Slow convergence (<0.9 cm/yr) favours strengthening of the ridge and build-up of stress at the ocean-continent transition allowing for subduction initiation at passive margins over subduction at mid-oceanic ridges. The results allow for identifying geodynamic processes that fit conditions for subduction nucleation at passive margins, which is relevant for the unique case of the Alps. We speculate that the slow Africa–Europe convergence between 130 and 85 Ma contributes to the strengthening of the mid-oceanic ridge, leading to subduction initiation at passive margin 60–70 Myr after rifting and passive margin formation.

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Section: Favourable Conditions For Subduction Initiation At Passive Marginssupporting

confidence: 89%

Section: Favourable Conditions For Subduction Initiation At Passive Marginsmentioning

confidence: 99%

Kinematic Boundary Conditions Favouring Subduction Initiation at Passive Margins Over Subduction at Mid-oceanic Ridges

2021

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“…Because a large age contrast across the transform fault is rare, the SSI model is unlikely to be widely applicable to SI on Earth. In contrast, the ISI model with young oceanic plates seem to explain the observations better (e.g., Keenan et al., 2016; Qing et al., 2021; Zhou & Wada, 2021). Geological observations indicate that some SI occurred at a transform boundary under transpression (Johnston et al., 2011; Lithgow‐Bertelloni & Guynn, 2004).…”

Section: Discussionmentioning

confidence: 99%

Effects of Elasticity on Subduction Initiation: Insight From 2‐D Thermomechanical Models

Zhou

Wada

2022

JGR Solid Earth

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“…The high geothermal gradient of metamorphic sole is not always the case during SI. Such a high-temperature condition at a shallow depth can hardly be obtained in other cases, including passive margins (e.g., Mueller & Phillips, 1991;Nikolaeva, et al, 2010;Zhong & Li, 2019, SI at a ceased spreading center/ridge for a long time (e.g., Qing et al, 2021), or the induced SI at transform fault/weak zone (e.g., Gurnis et al, 2019Gurnis et al, , 2004. For some of the SI at the southwest Pacific, the age of the overriding oceanic lithosphere during SI is generally over 10 Ma, which is too cold for the formation of metamorphic soles.…”

Section: The Ophiolite Without Metamorphic Solementioning

confidence: 99%

Formation of Metamorphic Soles Underlying Ophiolites During Subduction Initiation: A Systematic Numerical Study

Zhong

2022

JGR Solid Earth

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The understanding of subduction initiation (SI) remains ambiguous due to limited geological records. The metamorphic sole, generally considered to be generated by oceanic crustal metamorphism during SI, is characterized by high temperature condition (∼800°C) at shallow depths (<40 km). However, the exact tectonic setting of the metamorphic sole with such a high geothermal gradient is still controversial. The petrological and geochemical signatures of ophiolites and metamorphic soles in nature indicate three different types: (a) supra‐subduction zone (SSZ)‐type ophiolite with mid‐ocean ridge basalt (MORB)‐type metamorphic sole; (b) SSZ‐type ophiolite with SSZ‐type metamorphic sole; and (c) MORB‐type ophiolite with MORB‐type metamorphic sole. To clarify the conditions of metamorphic sole generation in different tectonic settings, a series of numerical models are conducted. The model results indicate that the SI at a (back‐arc) spreading center or spontaneous SI at a transform fault provides the favorable high‐temperature condition for formation of the metamorphic sole underlying the ophiolite. The former regime generates SSZ‐type ophiolite with SSZ‐type sole, whereas the latter generates SSZ‐type ophiolite with MORB‐type sole. The P‐T conditions of natural metamorphic soles may not represent the characteristic subduction channel condition for the majority of ophiolites, but stand for the end‐member high‐temperature regime that facilitates weakening, detachment and further exhumation of metamorphic soles. It thus illustrates the less widely distributed metamorphic soles than ophiolites in nature. The model results are further compared with three present‐day back‐arc basins on the Earth to evaluate the likelihood of future metamorphic sole generation and preservation in these basins.

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Dynamic Evolution of Induced Subduction Through the Inversion of Spreading Ridges

Cited by 14 publications

References 53 publications

Kinematic Boundary Conditions Favouring Subduction Initiation at Passive Margins Over Subduction at Mid-oceanic Ridges

Kinematic Boundary Conditions Favouring Subduction Initiation at Passive Margins Over Subduction at Mid-oceanic Ridges

Effects of Elasticity on Subduction Initiation: Insight From 2‐D Thermomechanical Models

Formation of Metamorphic Soles Underlying Ophiolites During Subduction Initiation: A Systematic Numerical Study

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