Trench migration, net rotation and slab–mantle coupling

Funiciello, Francesca; Faccenna, Claudio; Heuret, Arnauld; Lallemand, Serge; Giuseppe, Erika Di; Becker, T. W.

doi:10.1016/j.epsl.2008.04.006

Cited by 180 publications

(218 citation statements)

References 59 publications

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“…Viscosity of the overriding lithosphere, when present, is 2.9 × 10 4 Pa s and the viscosity of the mantle ranges between 30 and 40 Pa s. The obtained viscosity ratio between the slab and the upper mantle varies between 7.75×10 2 and 25×10 2 (Table 1), which is in the high range of proposed values (e.g. Billen et al, 2003;Faccenna et al, 2007;Funiciello et al, 2008;Wu et al, 2008;Loiselet et al, 2009Loiselet et al, , 2010. In the following, we directly express the quantities with their corresponding scaled values for a better relevance to real Earth.…”

Section: Setupmentioning

confidence: 71%

The dynamics of laterally variable subductions: laboratory models applied to the Hellenides

et al. 2013

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Abstract. We designed three-dimensional dynamically selfconsistent laboratory models of subduction to analyse the relationships between overriding plate deformation and subduction dynamics in the upper mantle. We investigated the effects of the subduction of a lithosphere of laterally variable buoyancy on the temporal evolution of trench kinematics and shape, horizontal flow at the top of the asthenosphere, dynamic topography and deformation of the overriding plate. Two subducting units, which correspond to a negatively buoyant oceanic plate and positively buoyant continental one, are juxtaposed via a trench-perpendicular interface (analogue to a tear fault) that is either fully-coupled or shear-stress free. Differential rates of trench retreat, in excess of 6 cm yr −1 between the two units, trigger a more vigorous mantle flow above the oceanic slab unit than above the continental slab unit. The resulting asymmetrical sublithospheric flow shears the overriding plate in front of the tear fault, and deformation gradually switches from extension to transtension through time. The consistency between our models results and geological observations suggests that the Late Cenozoic deformation of the Aegean domain, including the formation of the North Aegean Trough and Central Hellenic Shear zone, results from the spatial variations in the buoyancy of the subducting lithosphere. In particular, the lateral changes of the subduction regime caused by the Early Pliocene subduction of the old oceanic Ionian plate redesigned mantle flow and excited an increasingly vigorous dextral shear underneath the overriding plate. The models suggest that it is the inception of the Kefalonia Fault that caused the transition between an extension dominated tectonic regime to transtension, in the North Aegean, Mainland Greece and Peloponnese. The subduction of the tear fault may also have helped the propagation of the North Anatolian Fault into the Aegean domain.

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Section: Setupmentioning

confidence: 71%

The dynamics of laterally variable subductions: laboratory models applied to the Hellenides

et al. 2013

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“…Previous work has argued that the upper mantle is dominantly non-Newtonian and strain rate softening [Billen, 2008;Cizkova and Bina, 2013], which implies that the effective viscosity ratio between a slab and the ambient upper mantle should be relatively high. Nevertheless, the effective viscosity ratio that we use in our experiments (~160) is well within the previous estimates of approximately 50-500 [e.g., Schellart, 2008;Funiciello et al, 2008;Ribe, 2010;Wu et al, 2008;Loiselet et al, 2009;Li and Ribe, 2012]. For the density difference we consider a natural upper limit of Δρ = 80 kg m 3 , which would correspond to an old lithospheric slab in which all the oceanic crust has been altered to eclogite and with no heat diffusion into the slab.…”

Section: 1002/2014gl062876mentioning

confidence: 78%

How weak is the subduction zone interface?

Duarte

Schellart

Cruden

2015

Geophysical Research Letters

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Several lines of evidence suggest that subduction zones are weak and that the unique availability of water on Earth is a critical factor in the weakening process. We have evaluated the strength of subduction zone interfaces using two approaches: (i) from empirical relationships between shear stress at the interface and subduction velocity, deduced from laboratory experiments; and (ii) from a parametric study of natural subduction zones that provides new insights on subduction zone interface strength. Our results suggest that subduction is only mechanically feasible when shear stresses along the plate interface are relatively low (less than~35 MPa). To account for this requirement, we propose that there is a feedback mechanism between subduction velocity, water released from the subducting plate, and weakening of the fore-arc mantle that may explain how relatively low shear stresses are maintained at subduction interfaces globally.

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“…We invariably observe (relatively fast) slab rollback in these models, whereas on Earth not all subduction zones show strong rollback and advancing trenches are also proposed (e.g. Funiciello et al, 2008;Schellart et al, 2008). OO3 and OO6 are in fact endmember models as on Earth the global coupling between plates may impose far-field control on the velocity of both overriding and subducting plate.…”

Section: Constraining the Motion Of The Lithosphere Platesmentioning

confidence: 99%

Using open sidewalls for modelling self-consistent lithosphere subduction dynamics

et al. 2012

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Abstract. Subduction modelling in regional model domains, in 2-D or 3-D, is commonly performed using closed (impermeable) vertical boundaries. Here we investigate the merits of using open boundaries for 2-D modelling of lithosphere subduction. Our experiments are focused on using open and closed (free slip) sidewalls while comparing results for two model aspect ratios of 3:1 and 6:1. Slab buoyancy driven subduction with open boundaries and free plates immediately develops into strong rollback with high trench retreat velocities and predominantly laminar asthenospheric flow. In contrast, free-slip sidewalls prove highly restrictive on subduction rollback evolution, unless the lithosphere plates are allowed to move away from the sidewalls. This initiates return flows pushing both plates toward the subduction zone speeding up subduction. Increasing the aspect ratio to 6:1 does not change the overall flow pattern when using open sidewalls but only the flow magnitude. In contrast, for freeslip boundaries, the slab evolution does change with respect to the 3:1 aspect ratio model and slab evolution does not resemble the evolution obtained with open boundaries using 6:1 aspect ratio. For models with open side boundaries, we could develop a flow-speed scaling based on energy dissipation arguments to convert between flow fields of different model aspect ratios. We have also investigated incorporating the effect of far-field generated lithosphere stress in our open boundary models. By applying realistic normal stress conditions to the strong part of the overriding plate at the sidewalls, we can transfer intraplate stress to influence subduction dynamics varying from slab roll-back, stationary subduction, to advancing subduction. The relative independence of the flow field on model aspect ratio allows for a smaller modelling domain. Open boundaries allow for subduction to evolve freely and avoid the adverse effects (e.g. forced return flows) of free-slip boundaries. We conclude that open boundaries in combination with intraplate stress conditions are to be preferred for modelling subduction evolution (rollback, stationary or advancing) using regional model domains.

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Trench migration, net rotation and slab–mantle coupling

Cited by 180 publications

References 59 publications

The dynamics of laterally variable subductions: laboratory models applied to the Hellenides

The dynamics of laterally variable subductions: laboratory models applied to the Hellenides

How weak is the subduction zone interface?

Using open sidewalls for modelling self-consistent lithosphere subduction dynamics

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