Dynamics of back‐arc extension controlled by subducting slab retreat: Insights from 2D thermo‐mechanical modelling

Sheng, Jian; Li, Cunzhu; Liao, Jie; Yang, Zefa; Jiang, Shiyi

doi:10.1002/gj.3336

Cited by 3 publications

(2 citation statements)

References 68 publications

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“…The specific mode that a model produces depends on different parameters, including properties of the hot region and plate ages in our cases. There have been many studies investigating the role of plate ages on back-arc extension (Sdrolias and Müller, 2006;Capitanio et al, 2011;Sheng et al, 2019;Dasgupta et al, 265 2021) or slab/plate behaviours (Garel et al, 2014), so details will not be discussed in this study. When the plate ages are fixed and the model shows Thinning but no Extension before a hot region is introduced, some models show Extension at the hot region (Mode EH), which means the hotter and weaker 'arc' is split apart; whereas some others show Extension at the same place as the thinning location even though the weakened zone is much closer to the trench (Mode EF), which implies the driving force (including the force which weakens the OP) is undoubtedly enhanced.…”

Section: The Role Of An Existing Arcmentioning

confidence: 99%

How a volcanic arc influences back-arc extension: insight from 2D numerical models

Zhang,

Davies

2023

Preprint

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Abstract. Investigating plate tectonics through the lens of back-arc extension in subduction systems, this study introduces a 'hot region' on the overriding plate (OP) in 2D thermo-mechanical models, simulating the role of an arc. The models identified two extension locations on the OP: at the hot region (Mode EH) or surprisingly at a far-field location which is about 750 km from the trench (Mode EF). The study also found that extension could occur at the same far-field location without a hot region when the OP is young and thin, or the subducting plate (SP) is old and strong. Our models suggest that EH mode is common, occurring in many cases like Mariana Trough and Lau Basin, while the EF mode is rare, potentially occurring in scenarios like the Japan Sea. The primary driving mechanism in our models is poloidal flow beneath the OP, and the extension process is the competition of basal drag which thins the OP versus thermal healing which thickens it, and also a competition of thermal weakening at the hot region and at the far-field location. Increased trench retreat rates, facilitated by increased hot region temperature and width, encouraged this flow and consequently promoted back-arc extension.

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Section: The Role Of An Existing Arcmentioning

confidence: 99%

How a volcanic arc influences back-arc extension: insight from 2D numerical models

Zhang,

Davies

2023

Preprint

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“…In case of back‐arc rifting, where extension occurs in close proximity to an active subduction zone, additional controlling factors include the rate of trench‐retreat (partly controlled by relative plate motions and the age of the oceanic lithosphere), the pattern of asthenospheric flow in three dimensions, the absolute plate motions, and the long term strength of the subduction interface (Behr & Becker, 2018; Chen et al., 2015; Currie et al., 2008; Funiciello et al., 2003; Király et al., 2016; Magni et al., 2014; Schellart & Moresi, 2013; Schellart et al., 2007; Sdrolias & Müller, 2006; Sheng et al., 2018; Wolf & Huismans, 2019). Moreover, for back‐arc rifts both the rate of extension and the rheological setup of the overriding plate (two main controlling factors for continental rifts) are externally controlled factors.…”

Section: Introductionmentioning

confidence: 99%

Wide Versus Narrow Back‐Arc Rifting: Control of Subduction Velocity and Convective Back‐Arc Thinning

2022

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Back‐arc basins such as the ones behind the island‐arcs of the Western Pacific Ocean or the ones in the Mediterranean Sea are ubiquitous structures of the Earth. They are extensional basins forming in the overriding plate behind subduction zones and similarly to continental rifts, they can exhibit different structural styles from narrow, localized rifting to wide‐rift extension. While these different structural styles have been long recognized, the factors controlling the style of extension in these basins have not been explored properly. We use thermo‐mechanical models to investigate how the relative rates of progressive build‐up of slab‐pull force and of convective thinning and thermal weakening of the overriding plate control the style of back‐arc rifting. Following subduction‐initiation, a high subducting plate velocity results in rapid build‐up of the slab‐pull force. The relatively low rate of convectively thinning and associated moderate weakening of the overriding plate require slab‐pull to build up to close to its maximum value to overcome the high back‐arc integrated strength resulting in a narrow back‐arc rift. In turn a low subducting plate velocity in comparison with the timescale of convective thinning of the overriding plate allows for significant back‐arc weakening before the slab‐pull force becomes large enough to drive back‐arc extension. In this case, the back‐arc exhibits a wide rifting style as extension occurs at significantly reduced overriding plate integrated strength. Our model results provide an explanation why some subduction zones exhibit wide, distributed extension in the overriding plate such as for instance observed in the Pannonian basin.

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How a volcanic arc influences back-arc extension: insight from 2D numerical models

Zhang,

Davies

2024

Solid Earth

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Abstract. Investigating plate tectonics through the lens of back-arc extension in subduction systems, this study introduces a “hot region” onto an overriding plate (OP) in 2D thermo-mechanical models, simulating the role of an arc. The models identified two extension locations on the OP: Extension in the Hot region (mode EH) and Extension at a Far-field location (mode EF), which is about 750 km from the trench. The study also found that extension can occur at the same far-field location without a hot region when the OP is young and thin or when the subducting plate (SP) is old with a high sinking velocity. Our models suggest that the EH mode is common, occurring in many cases like the Mariana Trough and Lau Basin, while the EF mode is rare, potentially occurring in locations like the Japan Sea. The primary driving mechanism in our models is poloidal flow beneath the OP, and the extension process involves competition between basal drag, which thins the OP, and thermal healing, which thickens it, as well as competition between thermal weakening in the hot region and that at the far-field location. Increased trench retreat rates, facilitated by increased hot-region temperature and width, have encouraged this flow and have consequently promoted back-arc extension.

show abstract

Dynamics of back‐arc extension controlled by subducting slab retreat: Insights from 2D thermo‐mechanical modelling

Cited by 3 publications

References 68 publications

How a volcanic arc influences back-arc extension: insight from 2D numerical models

How a volcanic arc influences back-arc extension: insight from 2D numerical models

Wide Versus Narrow Back‐Arc Rifting: Control of Subduction Velocity and Convective Back‐Arc Thinning

How a volcanic arc influences back-arc extension: insight from 2D numerical models

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