Topography of the Moho and Conrad discontinuities in the Kyushu district, Southwest Japan

Oda, Hitoshi; Ushio, Takashi

doi:10.1007/s10950-007-9049-z

Cited by 29 publications

(28 citation statements)

References 16 publications

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“…We have chosen southwest Japan, where the crustal thickness is ~35 km (Oda and Ushio, 2007;Ueno et al, 2008), as a suitable natural laboratory (Fig. 1).…”

Section: Geological Background and Approachmentioning

confidence: 99%

Lower crustal H2O controls on the formation of adakitic melts

Zellmer

Iizuka

Miyoshi

et al. 2012

Geology

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“…We have chosen southwest Japan, where the crustal thickness is ~35 km (Oda and Ushio, 2007;Ueno et al, 2008), as a suitable natural laboratory (Fig. 1).…”

Section: Geological Background and Approachmentioning

confidence: 99%

Lower crustal H2O controls on the formation of adakitic melts

Zellmer

Iizuka

Miyoshi

et al. 2012

Geology

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“…The low-velocity zone beneath the Kyushu Mountains provides important insight into the tectonics of this region. Oda and Ushio (2007) estimated Moho relief from refracted P-wave data. As noted in Introduction, they inferred that the depth of the Moho is increases eastward and that the maximum depth is found in the area where Kyushu-Palau Ridge subducted.…”

Section: Beneath the Kyushu Mountainsmentioning

confidence: 99%

“…This gross structural trend is compatible with the observed Bouguer gravity anomaly, which is positive in western Kyushu and negative in eastern Kyushu. Oda and Ushio (2007) suggested that the shallow Moho and the low velocity zone estimated by Sadeghi et al (2000) reflects lower crustal erosion associated with a small-scale mantle upwelling in the Okinawa Trough and that the deeper Moho corresponds to the oceanic Moho of the subducting Kyushu-Palau ridge.…”

Section: Introductionmentioning

confidence: 99%

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Velocity structure in the crust beneath the Kyushu area

et al. 2010

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We present high-resolution three-dimensional tomographic images of the crust beneath the entire Kyushu arc, and particularly the western portion. Our results reveal a velocity anomaly that correlates well with an upper crustal gravity anomaly. Signi cant low-velocity anomalies exist beneath the Miyazaki plane and along the Beppu-Shimabara Graben. Another extensive low-velocity region near the bottom of the crust is located just below the volcanic front and between active volcanoes. The low-velocity anomalies exhibit low V p and V p /V s characteristics, and the spatial relationship between these anomalies, the Bouguer gravity anomaly, and the Moho suggests that low-density material at the base of the crust is responsible for both the seismic and gravity signatures. We interpret this material to constitute a relict ridge subducting below the Kyushu Mountains.

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“…3c), where intra-arc rifting takes place (Bird 2003). However, crustal thinning clearly cannot be called upon when considering the thickness of overriding crusts of Northern Chile (Yuan et al 2002), where crustal-scale convection may contribute to the high observed heat flux (Babeyko and SW Japan (Oda & Ushio 2007;Ueno et al 2008). These subduction zones are all built on thick to very thick continental crust.…”

Section: Effect Of Volatiles On Magma Differentiation and Ascentmentioning

confidence: 99%

Volatiles in subduction zone magmatism

Zellmer

Edmonds

Straub

2014

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Abstract:The volatile cycle at subduction zones is key to the petrogenesis, transport, storage and eruption of arc magmas. Volatiles control the flux of slab components into the mantle wedge, are responsible for melt generation through lowering the solidi of mantle materials, and influence the crystallizing phase assemblages in the overriding crust. Globally, magma ponding depths may be partially controlled by melt volatile contents. Volatiles also affect the rate and extent of degassing during magma storage and decompression, influence magma rheology and therefore control eruption style. The style of eruptions in turn determines the injection height of environmentally sensitive gases into the atmosphere and the impact of explosive arc volcanism. In this overview we summarize recent advances regarding the role of volatiles during slab dehydration, melt generation in the mantle wedge, magmatic evolution in the overriding crust, eruption triggering, and the release of some magmatic volatiles from volcanic edifices into the Earth's atmosphere.In contrast to mid-ocean ridge magmatism, where upwelling and adiabatic decompression of the mantle is the primary cause of melt generation, subduction zone magmatism is triggered by the depression of the mantle solidus due to influx of volatiles (dominantly There is ongoing debate about the processes that form extractable melts of the hydrated mantle wedge. One model suggests that efficient melt extraction requires a degree of melting of the wedge so large that melts are generally extracted at or above the 1300 8C isotherm, that is, close to the anhydrous solidus (Kushiro 1987;Schmidt & Poli 1998). The advective flux of heat carried by this melt then perturbs the location of the anhydrous solidus upwards (England & Katz 2010b), and melts eventually penetrate the lithosphere and enter the crust by hydrofracture and dyking. Alternatively, melting is dominated by decompression in slab and mantle diapirs that may rise upwards through the wedge (Behn et al. 2011).Here, we address volatile cycling from the dehydration of the subducting slab to arc volcanic degassing into the atmosphere (Fig. 1). A product of subduction is the output of volatiles as volcanic gases; another is the sinking of the slab containing 'residual' volatiles into the deep mantle. Volcanic gases in arcs are rich in H 2 O, chlorine, bromine and iodine compared to gases at rift and ocean island settings, which directly reflects the influence of slab-derived fluids on primary melt compositions by guest on May 10, 2018 http://sp.lyellcollection.org/ Downloaded from (Pyle & Mather 2009;Kutterolf et al. 2013; Kendrick et al. 2014a, b). Arc magmas are in general far richer in sulphur than their oceanic counterparts, reflecting the higher oxygen fugacity characteristic of arc melts and their enhanced capacity to carry dissolved sulphate (Wallace & Edmonds 2011). There is little direct evidence that primary arc melts are inherently richer in CO 2 than ocean island basalts, although it has been suggested that deep and pe...

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Topography of the Moho and Conrad discontinuities in the Kyushu district, Southwest Japan

Cited by 29 publications

References 16 publications

Lower crustal H2O controls on the formation of adakitic melts

Lower crustal H2O controls on the formation of adakitic melts

Velocity structure in the crust beneath the Kyushu area

Volatiles in subduction zone magmatism

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