Overriding Plate Deformation and Topography During Slab Rollback and Slab Rollover: Insights From Subduction Experiments

Xue, Kai; Schellart, Wouter P.; Strak, Vincent

doi:10.1029/2021tc007089

Cited by 21 publications

(25 citation statements)

References 68 publications

(163 reference statements)

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“…These stresses are generated by the horizontal basal traction at the base of the OP increasing towards the trench (Figure 5A; Figure 7A and Supplementary Figure S4A). Our results agree with earlier geodynamic studies that found overall OP extension during slab rollback and trench retreat (e.g., Duarte et al, 2013;Chen et al, 2015;Chen et al, 2016;Xue et al, 2022). Additionally, although previous 3D subduction models have shown the importance of toroidal mantle flow during the first phases of subduction (e.g., Piromallo et al, 2006;Schellart, 2008;Stegman et al, 2010) and have suggested that toroidal flow is the primary contributor to OP extension (e.g., Duarte et al, 2013;Meyer and Schellart, 2013;Schellart and Moresi, 2013;Chen et al, 2016), the poloidal mantle flow beneath the OP associated with slab rollback is still large enough to generate extensional stresses.…”

Section: Alboran Domain Deformationsupporting

confidence: 93%

The Gibraltar slab dynamics and its influence on past and present-day Alboran domain deformation: Insights from thermo-mechanical numerical modelling

Gea

Negredo²,

Mancilla³

2023

Front. Earth Sci.

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The origin and tectonic evolution of the Gibraltar Arc system is the result of a complex geodynamic evolution involving the convergence of the Eurasian and African plates and the dynamic impact of the Gibraltar slab. Although geologic and geophysical data collected in the last few years have increased our knowledge of the Gibraltar Arc region, it is still unclear which are the mechanical links between the Gibraltar slab and the past deformation of the overriding Alboran lithosphere, as well as to which degree this subduction system is presently active. In this study, we use 2D numerical modelling to investigate the impact of the Gibraltar slab dynamics on the deformation of the overriding Alboran lithosphere. Our model simulates a WE generic vertical section at an approximate latitude of 36°N and considers an initial setup at about Burdigalian times (∼20 Ma), when the subduction front position is relatively well constrained by recent tectonic reconstructions. Our modelling shows a switch in the overriding plate (OP) stress state from extensional stresses during the slab rollback to compressional stresses near the trench when the rollback velocity decreases, caused by the change in slab-induced mantle flow. We also find that much of the crustal and lithospheric deformation occur during fast slab rollback and OP extension in the first 10 Myr of evolution, while after that only moderate deformation associated with subduction is predicted. Finally, we find that despite the subduction rollback ceases, the ongoing motion of the deeper portion of the slab induces a mantle flow that causes some amount of west-directed basal drag of the Alboran lithosphere. This basal drag generates interplate compresional stresses compatible with the distribution of intermediate-depth earthquakes in western Alboran.

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Section: Alboran Domain Deformationsupporting

confidence: 93%

The Gibraltar slab dynamics and its influence on past and present-day Alboran domain deformation: Insights from thermo-mechanical numerical modelling

Gea

Negredo²,

Mancilla³

2023

Front. Earth Sci.

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“…Slab rollback also comes with negative dynamic topography, with amplitudes that are comparable to observed topographic variations (∼thousands of metres) in both numerical and analogue models (e.g. Husson 2006;Xue et al 2022). Finally, mantle flow at the scale of lithospheric plates may also contribute to long-term vertical motions of subduction arcs.…”

Section: M P L I C At I O N S F O R O T H E R S U B D U C T I O N Z O...mentioning

confidence: 53%

“…Slab rollback models also show extension in the upper plate (e.g. Xue et al 2022) leading to the formation of crustal-scale normal faults which may lead to discernable subsidence as well (e.g. Sternai et al 2014).…”

Section: M P L I C At I O N S F O R O T H E R S U B D U C T I O N Z O...mentioning

confidence: 99%

Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Rijsingen

Calais

Jolivet

et al. 2022

Geophysical Journal International

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Summary Geological estimates of vertical motions in the central part of the Lesser Antilles show subsidence on timescales ranging from 125.000 to 100 years, which has been interpreted to be caused by interseismic locking along the subduction megathrust. However, horizontal GNSS velocities show that the Lesser Antilles subduction interface is currently building up little to no elastic strain. Here we present new present-day vertical velocities for the Lesser Antilles islands and explore the link between short- and long-term vertical motions and their underlying processes. We find a geodetic subsidence of the Lesser Antilles island arc at 1-2 mm/yr, consistent with the ∼100-year trend derived from coral micro-atolls. Using elastic dislocation models, we show that a locked or partially-locked subduction interface would produce uplift of the island arc, opposite to the observations, hence supporting a poorly-coupled subduction. We propose that this long-term, margin-wide subsidence is controlled by slab dynamic processes, such as slab rollback. Such processes could also be responsible for the aseismic character of the subduction megathrust.

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“…The data produced for this research are available in this in-text data citation reference: Xue et al (2021) under the CC BY 4.0 license.…”

Section: Data Availability Statementmentioning

confidence: 99%

Overriding plate deformation and topography during slab rollback and slab rollover: insights from subduction experiments

Xue¹,

Schellart²,

Strak³

2021

Preprint

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Overriding plate deformation (OPD) and topography vary at different subduction zones, with some subduction zones showing mainly overriding plate extension and low topography (e.g. Mariana, Tonga, Izu-Bonin subduction zones), while some showing mainly shortening and elevated topography (e.g. Makran, southern Manila subduction zones). Here we investigate how different subduction modes, namely trench retreat and trench advance, affect OPD and generate corresponding topography with fully dynamic analogue models of time-evolving subduction in three-dimensional space. We conduct two sets of experiments, one of which is characterized by trench retreat and slab rollback, and the other characterized by trench advance and slab rollover. We compute the mantle flow, the overriding plate strain and topography during subduction using the particle image velocimetry technique (PIV). The overriding plate in the experiments showing continuous trench retreat experiences overall extension, while in the experiments with trench advance following trench retreat it experiences overall shortening. The overriding plate in both trench retreat and trench advance subduction modes present fore-arc shortening and intra-arc extension. Our experiments indicate that the overall OPD except in the fore-arc region is mainly driven by the horizontal mantle flow at the base of the OP inducing a viscous drag force (FD), and is determined by the gradient of the horizontal mantle flow velocity (dvx/dx). Furthermore, a large-scale trenchward overriding plate tilting and an overall subsidence of the overriding plate were observed in the experiments showing continuous trench retreat, while a landward tilting and an overall uplift of the overriding plate were observed during long-term trench advance. The two types of topography during the two different subduction modes can be ascribed to the large-scale trenchward and landward mantle flow, respectively, and thus represent forms of dynamic topography. Our models showing trench advance provide a possible mechanism for OPD in the Makran subduction zone, which has experienced overall trench-normal tectonic shortening in the overriding plate, but shows extension in a local region of the coastal Makran that is spatially comparable to that in our experiments.&#160; In addition, these models might also provide an explanation for the regional topography at the Makran subduction zone, which shows a long-wavelength topographic high in the overriding plate near the trench that decreases northward.

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Overriding Plate Deformation and Topography During Slab Rollback and Slab Rollover: Insights From Subduction Experiments

Cited by 21 publications

References 68 publications

The Gibraltar slab dynamics and its influence on past and present-day Alboran domain deformation: Insights from thermo-mechanical numerical modelling

The Gibraltar slab dynamics and its influence on past and present-day Alboran domain deformation: Insights from thermo-mechanical numerical modelling

Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Overriding plate deformation and topography during slab rollback and slab rollover: insights from subduction experiments

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