Influences of the buoyancy of partially molten rock on 3-D plume patterns and melt productivity above retreating slabs

Zhu, Guizhi; Gerya, Taras; Honda, Sawao; Tackley, P. J.; Yuen, David A.

doi:10.1016/j.pepi.2011.02.005

Cited by 21 publications

(26 citation statements)

References 36 publications

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“…9) thermo-mechanical models including water transport and melting. These models predicted (Zhu et al, 2009(Zhu et al, , 2011. (v) Large-scale rigid body rotation phenomena in subduction zones due to inhomogeneous hydration and cooling of the mantle wedge Nikolaeva et al, 2008).…”

Section: Small-scale Convection and Thermal-chemical Plumes In The Mamentioning

confidence: 94%

“…Several numerical experiments outline spontaneous subduction initiation across a pre-existing oceanic fracture zone in both 2D (e.g., Gerya et al, 2008a;Nikolaeva et al, 2008;Gerya, 2010) and 3D (e.g., Zhu et al, 2009Zhu et al, , 2011 without emphasis on the initiation process itself. Stable subduction initiation occurs for cases with a large cooling age contrasts between contacting plates (0.1-10 Myr vs. 40-90 Myr), combined with low strength (1-3 MPa) and large width and depth (≥20 km × 20 km) of the pre-existing fracture zone (Fig.…”

Section: Subduction Initiationmentioning

confidence: 99%

“…Further complications may come from three-dimensional aspects of the plate structure near pre-existing fracture zones such as transform faults. To date all subduction initiation experiments consider either 2D models (e.g., Hall et al, 2003;Gurnis et al, 2004;Nikolaeva et al, 2008Nikolaeva et al, , 2010, or laterally uniform plate boundary in 3D models (Zhu et al, 2009(Zhu et al, , 2011. In contrast, oceanic transform faults are characterized by notable lateral variations in the thermal and rheological structure and the buoyancy of the contacting plates, which could strongly affect likelihood and dynamics of subduction initiation in this geodynamic setting.…”

Section: Subduction Initiationmentioning

confidence: 99%

“…Considering potential links between subduction initiation and lithospheric thinning (Nikolaeva et al, 2010(Nikolaeva et al, , 2011, additional study areas may also include (Sobolev, personal communication) the East African margin, which has been strongly affected by the recent Afar plume activity (e.g., Pérez-Gussinyé et al, 2009). Future technical advances will likely be directed toward modeling of subduction initiation in 3D with realistic high-resolution global (e.g., Stadler et al, 2010) and regional (e.g., Zhu et al, 2009Zhu et al, , 2011 models, including free plate surfaces that can take into account actual plate configurations, the geometry of passive margin, oceanic transform/fracture zones and the distribution of continental/oceanic topography.…”

Section: Subduction Initiationmentioning

confidence: 99%

“…• Development of asymmetric one-sided terrestrial-style subduction by water-related weakening of plate interfaces ; • Seismic velocity structures associated with hydration and melting in the mantle wedge (e.g., Nikolaeva et al, 2008;Gerya and Meilick, 2011); • Magmatic productivity above slabs and the dynamics of crustal growth in volcanic arcs driven by water and melt transport (Gorczyk et al, 2007a,b;Nikolaeva et al, 2008;Zhu et al, 2009Zhu et al, , 2011Gerya and Meilick, 2011); • Slab dehydration and water-induced convection in the Earth's mantle transition zone (Richard et al, 2006;Richard and Bercovici, 2009); • Deep slab hydration induced by bending related variations in tectonic pressure (Faccenda et al, 2009). …”

Section: Fluid and Melt Transport In Subduction Zonesmentioning

confidence: 99%

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Future directions in subduction modeling

Gerya¹

2011

Journal of Geodynamics

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Section: Small-scale Convection and Thermal-chemical Plumes In The Mamentioning

confidence: 94%

Section: Subduction Initiationmentioning

confidence: 99%

Section: Subduction Initiationmentioning

confidence: 99%

Section: Subduction Initiationmentioning

confidence: 99%

Section: Fluid and Melt Transport In Subduction Zonesmentioning

confidence: 99%

See 3 more Smart Citations

Future directions in subduction modeling

Gerya¹

2011

Journal of Geodynamics

244

103

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A systematic 2‐D investigation into the mantle wedge's transient flow regime and thermal structure: Complexities arising from a hydrated rheology and thermal buoyancy

Voci

Davies

Goes

et al. 2014

Geochem Geophys Geosyst

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[1] Arc volcanism at subduction zones is likely regulated by the mantle wedge's flow regime and thermal structure and, hence, numerous studies have attempted to quantify the principal controls on mantle wedge conditions. In this paper, we build on these previous studies by undertaking a systematic 2-D numerical investigation into how a hydrated rheology and thermal buoyancy influence the wedge's flow regime and associated thermal structure. We quantify the role of a range of plausible: (i) water contents (0-5000 H/10 6 Si); (ii) subduction velocities (2-10 cm/yr); and (iii) upper-plate ages (50-120 Myr), finding that small-scale convection (SSC), resulting from Rayleigh-Taylor instabilities, or drips, off the base of the overriding lithosphere, is a typical occurrence. The morphology of SSC varies with viscosity and subduction parameters, with drips at their most prominent when subduction velocities and wedge viscosities are low. Our results confirm that high subduction velocities and wedge viscosities promote a dominantly corner-flow regime, and strong upper-plate erosion below the arc region. By contrast, we find that back-arc upper-plate erosion by SSC is largely controlled by wedge viscosity, occurring when: (i) viscosities are < 5Á10 18 Pa s; and (ii) the length of the upper plate, available for destabilization, exceeds the characteristic wavelength of instabilities. Thus, if hydrous weakening of wedge rheology extends at least 100-150 km from the trench, our 2-D models predict an unstable flow regime, resulting in temperature fluctuations of 50-100 K, which are sufficient to influence melting and the stability of hydrous minerals.

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Numerical modeling of geochemical variations caused by crustal relamination

Vogt

Castro

Gerya

2013

Geochem Geophys Geosyst

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[1] Geochemical consequences of composite diapirs formed in subduction zones have been studied using a thermomechanical numerical model of an ocean-continent subduction zone. This model includes dehydration of subducted crust, aqueous fluid transport, partial melting, and melt emplacement. Subduction of crustal material to sublithospheric depth results in the formation of a tectonic rock mélange composed of basalt, sediment, and hydrated /serpentinized mantle. At asthenospheric depth, this rock mélange may evolve into partially molten diapirs and rise through the mantle prior to emplacement (relamination) at crustal levels. We have investigated the composition and the geochemical evolution of liquids derived from such composite diapirs by analyzing the differing proportions of the crustal end-members in the source, i.e., basalt and sediment. Our results show that the proportions of the components (in the diapiric mélange) are limited to short-range variations within an interval of X b [=volume fraction of basalt/(basalt + sediment)] = 0.4 À 0.8, yielding melt with a relatively stable granodioritic major element composition. Hence, granodioritic melt is transported by rising composite diapirs to crustal levels, contributing to the growth of the continental crust. In addition to this, we have calculated Sr and Nd isotopic initial ratios of the diapiric mélange as a function of time, based on the fraction of the components in the mélange. Liquids derived from composite diapirs inherit the geochemical characteristics of the composite source and show distinct temporal variations of radiogenic isotopes depending on the changing values of X b . Partial melting of composite diapirs is therefore expected to produce melt with a constant major element composition but substantial changes in terms of radiogenic isotopes.

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Influences of the buoyancy of partially molten rock on 3-D plume patterns and melt productivity above retreating slabs

Cited by 21 publications

References 36 publications

Future directions in subduction modeling

Future directions in subduction modeling

A systematic 2‐D investigation into the mantle wedge's transient flow regime and thermal structure: Complexities arising from a hydrated rheology and thermal buoyancy

Numerical modeling of geochemical variations caused by crustal relamination

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