Supply rate of continental materials to the deep mantle through subduction channels

Ichikawa, Hiroki; Kawai, Kenji; Yamamoto, Shinji; Kameyama, Masanori

doi:10.1016/j.tecto.2013.02.001

Cited by 16 publications

(30 citation statements)

References 48 publications

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“…This will be a similar problem on the delamination of subducted oceanic crust (e.g., van Keken et al 1996;Karato 1997). As for the delamination from a subducting slab above 270 km, Ichikawa et al (2013aIchikawa et al ( , 2015, this volume) conducted a numerical simulation of a granitic subduction channel based on the finite difference method and found that a sustainable thickness of the channel in the deep mantle is ~2-3 km and that its corresponding flux of continental materials integrated over the length of the (Fig. 8.1).…”

Section: Discussionmentioning

confidence: 95%

“…Previous studies suggested that high concentrations of radioactive elements produce a temperature increase of ~200 K for 200 My Ichikawa et al 2013a). This temperature increase will produce the upwelling plume due to the thermal instability, which might be related to the supercontinental cycle (Ichikawa et al 2013b).…”

Section: Discussionmentioning

confidence: 99%

“…If a considerable amount of granitic materials were accumulated at around 660 km, radioactive elements included could affect the thermal history in the mantle (Ichikawa et al 2013a(Ichikawa et al , b, 2015. Previous studies suggested that high concentrations of radioactive elements produce a temperature increase of ~200 K for 200 My Ichikawa et al 2013a).…”

Section: Discussionmentioning

confidence: 99%

“…Against such a traditional view, ubiquitous subduction of continental crust was proposed by both geophysical and geological studies at convergent plate boundary, which suggest new concepts of tectonic erosion (Scholl and von Huene 2007) and arc subduction (Yamamoto et al 2009). Moreover, recent geodynamic studies have suggested that the subduction channel between the subducted slab and mantle wedge could have a potential to carry a considerable amount of granitic material into the deep mantle due to a drag force from the subducting slab (Ichikawa et al 2013a(Ichikawa et al , 2015. Since the granitic materials possess a large amount of incompatible element and radiogenic nuclide (e.g., Hofmann 1997), the fate and amount of subducted granitic materials must be of importance in geochemistry and also in the terrestrial thermal history .…”

Section: Introductionmentioning

confidence: 99%

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Elasticity of Continental Crust Around the Mantle Transition Zone

Kawai

Tsuchiya

2015

The Earth's Heterogeneous Mantle

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The fate and amount of granitic materials subducted into the deep mantle are still under debate. The density, elastic property, and phase stability of granitic materials in the mantle pressures are key to clarifying them. Here, we modeled highpressure properties of the granitic assemblage by using ab initio mineral physics data of grossular garnet, K-hollandite, jadeite, stishovite, and calcium ferrite (CF)-type phase. We find that the ongoing subducting granitic assemblage, such as sediments and average upper crust rocks, is much denser than pyrolite in the pressure range from 9 GPa (~270 km), at which coesite undergoes a phase transition to stishovite, to around 27 GPa (~740 km). Above this pressure, granitic material becomes less dense than a pyrolite. This indicates that the granitic assemblage becomes gravitationally stable at the base of the mantle transition zone (MTZ). Results suggest a possibility that the granitic materials could accumulate around the 740 km depth if carried into the depth deeper than 270 km and segregated at some depth. Comparison of the velocities between granitic and pyrolitic materials shows that granitic materials can produce substantial velocity anomalies in the MTZ and the uppermost lower mantle (LM). Seismic observations such as anomalously fast velocities, especially for the shear wave, around the 660-km discontinuity, the complexity of 660-km discontinuity, and the scatterers in the uppermost LM could be associated with the subducted granitic materials.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Elasticity of Continental Crust Around the Mantle Transition Zone

Kawai

Tsuchiya

2015

The Earth's Heterogeneous Mantle

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“…On the other hand, according to a 1-D numerical simulation, the subduction channels of thickness of 2-3 km at the surface are able to reach 270 km in depth (Ichikawa et al 2013b). This suggests that a large portion of low-density materials such as upper continental crust can sink into the deep mantle as pointed out by Dobrzhinetskaya et al (2006), Irifune et al (1994), and Afonso and Zlotnik (2011).…”

Section: Introductionmentioning

confidence: 99%

Effect of Water on Subduction of Continental Materials to the Deep Earth

Ichikawa

Kawai

Yamamoto

et al. 2015

The Earth's Heterogeneous Mantle

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The flows in the subduction channels with wet mantle wedge are calculated by 1-D finite difference method with fine numerical resolutions. The water content largely affects the viscosity of the mantle wedge. Previous simulation result using dry rheology on the mantle wedge shows that viscosity of the subduction channels controls the process and that the sustainable thickness of the channel in the deep mantle is ~2-3 km. However, little is known about the effect of the water content in the mantle wedge on the subduction channels. Here, in order to estimate the supply rate of continental materials to the deep mantle with water-rich environment on the mantle wedge, we have conducted a numerical simulation of a subduction channel. The results show that the water content controls the flux of the continental materials especially when temperature of mantle wedge is high. Therefore, the water content of the mantle wedge can be more important in the ancient mantle because of its high temperature.

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Sound velocities of aluminum‐bearing stishovite in the mantle transition zone

Gréaux

Kono

Wang

et al. 2016

Geophysical Research Letters

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The elasticity of Al‐bearing stishovite with 1.0, 3.3, and 4.5 wt % Al2O3 was investigated in the multianvil apparatus at high pressures and temperatures up to 21 GPa and 1700 K, by ultrasonic interferometry in conjunction with in situ X‐ray techniques. The moduli KS and G are found to decrease with increasing Al2O3 content, while their pressure and temperature derivatives do not change in a significant manner for 1.0 and 3.3 wt % Al2O3. The temperature derivatives for 4.5 wt % Al2O3, however, are larger, which may result from a change in the Al substitution mechanism at high Al2O3 content. It is shown that acoustic velocities of any mid‐ocean ridge basalt are lower by −0.4% than those calculated from pure stishovite data. Velocity perturbations up to −3.4% (VP) and −4.2% (VS) in subducted slabs are explained by the combination of the thermal equilibration (ΔT ~ 600 K) of the slab and Al enrichment in stishovite.

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Supply rate of continental materials to the deep mantle through subduction channels

Cited by 16 publications

References 48 publications

Elasticity of Continental Crust Around the Mantle Transition Zone

Elasticity of Continental Crust Around the Mantle Transition Zone

Effect of Water on Subduction of Continental Materials to the Deep Earth

Sound velocities of aluminum‐bearing stishovite in the mantle transition zone

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