Subduction initiation at passive continental margins: A review based on numerical studies

Zhong, Xinyi; Li, Zhong‐Hai

doi:10.1016/j.sesci.2021.06.001

Cited by 20 publications

(10 citation statements)

References 89 publications

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“…In the current model, the weak zone extends along the entire OCT; however, if the weakness only appears in specific segments of the OCT, its contribution to the SI will be greatly reduced. The importance of existing weakness or weakening mechanism for SI has been widely studied (Arcay et al, 2020;Hall, 2018;Niu et al, 2003;Regenauer-Lieb et al, 2001;Zhou et al, 2018Zhou et al, , 2020 as summarized in Zhong and Li (2021). Several potential weakening mechanisms have been suggested for the OCT zone, such as serpentinization of mantle rocks (e.g., Pinto et al, 2017), hydration (e.g., Regenauer -Lieb et al, 2001), inherited weak zones or faults (e.g., Baes et al, 2011;Zhou et al, 2020), thermal softening (e.g., Kiss et al, 2020), and shear-heating (e.g., Auzemery et al, 2020).…”

Section: What Controls the Absence Of Si In Southern Indian Continent...mentioning

confidence: 99%

Wedge‐Shaped Southern Indian Continental Margin Without Proper Weakness Hinders Subduction Initiation

Zhong

2022

Geochem Geophys Geosyst

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In the general history of the earlier Tethyan evolution, the younger oceanic plate began subduction shortly after the terrane collision and closure of the neighboring older ocean (Table S1 in the Supporting Information S1). For example, the subduction of Neo-Tethyan oceanic plate initiated at about 10-20 Myrs after the collision of Cimmerian terranes with Eurasia (Stampfli & Borel, 2002;Wan et al., 2019;Zhong & Li, 2020). However, there is no clear sign for subduction initiation (SI) in the present-day northern Indian Ocean, although it has been more than 50 Myrs since the collision between Indian and Eurasian continental plates (Stern, 2004;.The absence of SI in the Indian Ocean is thus a puzzling and widely debated issue. One possible reason is the high strain localization in the relatively weak Tibetan plate, which thus hinders the stress building in the Indian oceanic plate. However, this explanation is challenged by the high gravitational potential energy of the present

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Section: What Controls the Absence Of Si In Southern Indian Continent...mentioning

confidence: 99%

Wedge‐Shaped Southern Indian Continental Margin Without Proper Weakness Hinders Subduction Initiation

Zhong

2022

Geochem Geophys Geosyst

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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, 2020, 2021), 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., 2019, 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: Discussionmentioning

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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“…Therefore, the horizontally forced SZI model is preferred to overcome the increasing strength of the cooling lithosphere [76,78,81]. The far-field external horizontal forces can be caused by the mid-ocean ridge, mantle plume, neighboring sinking slab, and large-scale mantle convection [82]. However, [83] argues that vertical forces can accelerate, propagate, and facilitate the development of self-sustaining subduction zones that are initially dominated by horizontal forces.…”

Section: Subduction Zone Initiation (Szi)mentioning

confidence: 99%

The Ampferer-Type Subduction: A Case of Missing Arc Magmatism

El-Rus¹,

Khudier²,

Hamid³

et al. 2023

Updates in Volcanology - Linking Active Volcanism and the Geological Record

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Ampferer-type subduction is a term that refers to the foundering of hyper-extended continental or embryonic oceanic basins (i.e., ocean-continent transitions) at passive continental margins. The lithospheric mantle underlying these rift basins is mechanically weaker, less dense, and more fertile than the lithospheric mantle underlying bounded continents. Therefore, orogens resulting from the closure of a narrow, immature extensional system are essentially controlled by mechanical processes without significant thermal and lithologic changes. Self-consistent, spontaneous subduction initiation (SI) due to the density contrast between the lithosphere and the crust of ocean-continent transitions is unlikely to occur. Additional far-field external horizontal forces are generally required for the SI. When the lithosphere subducts, the upper crust or serpentinized mantle and sediments separate from the lower crust, which becomes accreted to the orogen, while the lower crust subducts into the asthenosphere. Subduction of the lower crust, which typically consists of dry lithologies, does not allow significant flux-melting within the mantle wedge, so arc magmatism does not occur. As a result of melting inhibition within the mantle wedge during Ampferer-type subduction zones, the mantle beneath the resulting orogenic belts is fertile and thus has a high potential for magma generation during a subsequent breakup (i.e., magma-rich collapse).

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Subduction initiation at passive continental margins: A review based on numerical studies

Cited by 20 publications

References 89 publications

Wedge‐Shaped Southern Indian Continental Margin Without Proper Weakness Hinders Subduction Initiation

Wedge‐Shaped Southern Indian Continental Margin Without Proper Weakness Hinders Subduction Initiation

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

The Ampferer-Type Subduction: A Case of Missing Arc Magmatism

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