Compression at Strike‐Slip Fault Is a Favorable Condition for Subduction Initiation

Zhong, Xinyi; Li, Zhong‐Hai

doi:10.1029/2022gl102171

Cited by 3 publications

(2 citation statements)

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“…Similarly, the back‐arc basins are generally composed of relatively weaker plates/terranes, due to the hydration from the subducting slab, relatively higher strain rate and lower lithospheric age (Arcay et al., 2006; Billen & Gurnis, 2001). Moreover, the transform faults or oceanic fracture zones are vertical weak belts cutting through the whole plate, leading to lithospheric weakening, which are widely considered to facilitate the SI (Baes et al., 2011; Boutelier & Beckett, 2018; Hall et al., 2003; Mueller & Phillips, 1991; Shuck et al., 2021; Sutherland et al., 2020; Toth & Gurnis, 1998; Zhong & Li, 2023; Zhou et al., 2020). As a summary, the lithospheric weakness may come from variable tectonic processes; this study does not aim to distinguish them, but instead applies variable degrees of terrane weakening to test their effects on the mode selection of terrane collision‐induced SI.…”

Section: Discussionmentioning

confidence: 99%

Terrane Collision‐Induced Subduction Initiation: Mode Selection and Implications for Western Pacific Subduction System

Cui,

2024

Geochem Geophys Geosyst

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In the regime of plate tectonics, the subduction of an oceanic plate generally terminates with the collision and accretion of continental terranes. Then, a new subduction zone may form in the neighboring oceanic plates, which is defined as the terrane collision‐induced subduction initiation (SI). Based on the analyses of the western Pacific subduction system in the Cenozoic, three types of collision‐induced SI have been observed: subduction polarity reversal, subduction transference and far‐field subduction. However, the dynamics and controlling factors of SI mode selection after terrane collision are not clear. In this study, a multi‐terrane collision model has been conducted with variable rheological strength of continental terranes and different convergence velocities. The model results indicate that the relative strength of the terranes controls the SI mode selection, with the new subduction zone tending to form beneath weaker terranes. In addition, the higher convergence velocity can facilitate the collision‐induced SI. An analytical study of force balance has been further conducted, which provides a mechanical explanation for the numerical prediction of a weak overriding terrane as a favorable SI site. The numerical models and force balance analyses are further compared with the natural cases in the western Pacific subduction system. This indicates that subduction polarity reversal is the most favorable mode after terrane collision in the western Pacific, possibly due to the weakness of overriding plate during the preceding subduction‐induced fluid/melt activity. This comprehensive study provides systematic constraints for the dynamics of collision‐induced subduction jump, especially for the western Pacific subduction zones in the Cenozoic.

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Section: Discussionmentioning

confidence: 99%

Terrane Collision‐Induced Subduction Initiation: Mode Selection and Implications for Western Pacific Subduction System

Cui,

2024

Geochem Geophys Geosyst

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“…We solve for the Stokes equations using traditional formulations used in geodynamics (Moresi et al, 2000;Ismail-Zadeh and Tackley, 2010) and show that a component of strike-slip motion can substantially reduce the strength of a nascent plate boundary while providing a triggering mechanism to nucleate a new subduction zone. The idea that strike-slip motion produces a more favorable condition for the far-field compression to induce subduction is examined by Zhong and Li (2023) with 3D models. Here, we address this problem with a sliced 3D geometry extended from the trenchperpendicular cross-section (x-z dimension), with an additional trench-parallel dimension (y-dimension) that accounts for the strike-slip motion (Supplementary Figure S1).…”

Section: Model Formulationmentioning

confidence: 99%

Strike slip motion and the triggering of subduction initiation

Gurnis

2023

Front. Earth Sci.

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Plate tectonic reconstructions of three of the best-defined Cenozoic subduction initiation (SI) events in the western Pacific, Izu-Bonin-Mariana, Vanuatu, and Puysegur subduction zones, show substantial components of strike-slip motion before and during the subduction initiation. Using computational models, we show that strike-slip motion has a large influence on the effective strength of incipient margins and the ease of subduction initiation. The parameter space associated with visco-elasto-plastic rheologies, plate weakening, and plate forces and kinematics is explored and we show that subduction initiates more easily with a higher force, a faster weakening, or greater strike-slip motion. With the analytical solution, we demonstrate that the effect of strike-slip motion can be equivalently represented by a modified weakening rate. Along transpressive margins, we show that a block of oceanic crust can become trapped between a new thrust fault and the antecedent strike-slip fault and is consistent with structural reconstructions and gravity models of the Puysegur margin. Together, models and observations suggest that subduction initiation can be triggered when margins become progressively weakened to the point that the resisting forces become smaller than the driving forces, and as the negative buoyancy builds up, the intraplate stress eventually turns from compressional into extensional. The analytical formulation of the initiation time, tSI, marking the moment when intraplate stress flips sign, is validated with a computational models. The analytical solution shows that tSI is dominated by convergence velocity, while the plate age, strike-slip velocity, and weakening rate all have a smaller but still important effect on the time scale of subduction initiation.

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Subduction initiation at an oceanic transform fault experiencing compression: Role of the fault structure and of the brittle-ductile transition depth

Arcay

Abecassis

Lallemand

2023

Earth and Planetary Science Letters

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Compression at Strike‐Slip Fault Is a Favorable Condition for Subduction Initiation

Abstract: Subduction initiation (SI) remains a confusing problem today, especially for how and where the subduction zones begin (

Cited by 3 publications

References 57 publications

Terrane Collision‐Induced Subduction Initiation: Mode Selection and Implications for Western Pacific Subduction System

Terrane Collision‐Induced Subduction Initiation: Mode Selection and Implications for Western Pacific Subduction System

Strike slip motion and the triggering of subduction initiation

Subduction initiation at an oceanic transform fault experiencing compression: Role of the fault structure and of the brittle-ductile transition depth

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