Magmagenesis within the Hunter Ridge Rift Zone resolved from olivine-hosted melt inclusions and geochemical modelling with insights from geodynamic models

Durance, Patricia; Jadamec, M. A.; Falloon, Trevor J.; Nicholls, I.A.

doi:10.1080/08120099.2012.682096

Cited by 12 publications

(15 citation statements)

References 74 publications

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“…From these 3‐D flows, it is the toroidal return flow, driven by slab rollback and trench retreat, that drives backarc extension (section 4.2.1 and Figures , , , and ). Seismic anisotropy studies and geochemical studies indeed imply strong toroidal mantle return flow for Scotia [e.g., Livermore , ; Leat et al ., ; Müller et al ., ], Calabria [e.g., Trua et al ., ; Civello and Margheriti , ], Tonga [e.g., Turner and Hawkesworth , ; Smith et al ., ; Foley and Long , ], and New Hebrides [e.g., Heyworth et al ., ; Király et al ., ; Durance et al ., ]. The rapid backarc extension and the implied strong toroidal return flow at these subduction zones are in agreement with the predictions of our 3‐D numerical models.…”

Section: Discussionsupporting

confidence: 88%

A new driving mechanism for backarc extension and backarc shortening through slab sinking induced toroidal and poloidal mantle flow: Results from dynamic subduction models with an overriding plate

2013

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[1] We present numerical subduction models to investigate overriding plate deformation at subduction zones. All models show forearc shortening, resulting predominantly from shear stresses at the subduction zone interface and opposite-sense mantle shear stresses at the base of the forearc lithosphere. Models dominated by backarc extension show that it results from trench-normal positive velocity gradients in the mantle below the overriding plate. Such gradients result from toroidal mantle flow induced by slab rollback, with velocities below the leading part of the backarc faster than the overriding plate velocity. The velocity gradients induce basal shear stresses that increase trenchward and cause trenchward overriding plate motion at a velocity (v OP⊥ ) whose spatial average is below the trench retreat velocity (v T⊥ ). The combination of basal shear stresses and average v OP⊥ < v T⊥ causes trench-normal deviatoric tension in the backarc and backarc extension. Models dominated by backarc shortening show that it results from a relatively immobile subduction hinge and trenchward overriding plate motion driven by poloidal mantle flow. The poloidal mantle flow is induced by downdip slab sinking and causes the average v OP⊥ > v T⊥ . This results in trench-normal deviatoric compression and shortening in the leading part of the overriding plate as it collides with the subduction hinge. Ultimately, the geodynamic models demonstrate that backarc extension is favored for narrow slabs and near lateral slab edges and is driven by rollback induced toroidal mantle flow, while backarc shortening is favored for the center of wide slabs and is driven by poloidal mantle flow resulting from downdip slab motion.Citation: Schellart, W. P., and L. Moresi (2013), A new driving mechanism for backarc extension and backarc shortening through slab sinking induced toroidal and poloidal mantle flow: Results from dynamic subduction models with an overriding plate,

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Section: Discussionsupporting

confidence: 88%

A new driving mechanism for backarc extension and backarc shortening through slab sinking induced toroidal and poloidal mantle flow: Results from dynamic subduction models with an overriding plate

2013

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“…This study is based on results from 5 voyages to the southern termination of the Vanuatu Trench-North Fiji Basin-Hunter Ridge area between 1990-2009. These voyages include cruise 17 of the RV Akademik Alexander Nesmeyanov in 1990 (Pushchin 1990;Sigurdsson et al, 1993), the 1994 'ProFeTi' cruise of the RV Alis (Fleutelot et al, 2005;Durance et al, 2012) and three voyages of the RV Southern Surveyor in 2004and 2009(Patriat et al, 2015.…”

Section: Samplingmentioning

confidence: 99%

Subduction initiation terranes exposed at the front of a 2 Ma volcanically-active subduction zone

Patriat

Falloon

Danyushevsky

et al. 2019

Earth and Planetary Science Letters

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“…The subduction termination at the southern end of the New Hebrides subduction zone is an example where such complex 3-D processes occur, resulting in a diverse range of primitive subduction related magmas [Monzier et al, , 1997Sigurdsson et al, 1993;Danyushevsky et al, 2006Danyushevsky et al, , 2008Durance et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

Propagation of back‐arc extension into the arc lithosphere in the southern New Hebrides volcanic arc

Patriat

Collot

Danyushevsky

et al. 2015

Geochem Geophys Geosyst

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New geophysical data acquired during three expeditions of the R/V Southern Surveyor in the southern part of the North Fiji Basin allow us to characterize the deformation of the upper plate at the southern termination of the New Hebrides subduction zone, where it bends eastward along the Hunter Ridge. Unlike the northern end of the Tonga subduction zone, on the other side of the North Fiji Basin, the 908 bend does not correspond to the transition from a subduction zone to a transform fault, but it is due to the progressive retreat of the New Hebrides trench. The subduction trench retreat is accommodated in the upper plate by the migration toward the southwest of the New Hebrides arc and toward the south of the Hunter Ridge, so that the direction of convergence remains everywhere orthogonal to the trench. In the back-arc domain, the active deformation is characterized by propagation of the back-arc spreading ridge into the Hunter volcanic arc. The N-S spreading axis propagates southward and penetrates in the arc, where it connects to a sinistral strike-slip zone via an oblique rift. The collision of the Loyalty Ridge with the New Hebrides arc, less than two million years ago, likely initiated this deformation pattern and the fragmentation of the upper plate. In this particular geodynamic setting, with an oceanic lithosphere subducting beneath a highly sheared volcanic arc, a wide range of primitive subduction-related magmas has been produced including adakites, island arc tholeiites, back-arc basin basalts, and medium-K subduction-related lavas.

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Magmagenesis within the Hunter Ridge Rift Zone resolved from olivine-hosted melt inclusions and geochemical modelling with insights from geodynamic models

Cited by 12 publications

References 74 publications

A new driving mechanism for backarc extension and backarc shortening through slab sinking induced toroidal and poloidal mantle flow: Results from dynamic subduction models with an overriding plate

A new driving mechanism for backarc extension and backarc shortening through slab sinking induced toroidal and poloidal mantle flow: Results from dynamic subduction models with an overriding plate

Subduction initiation terranes exposed at the front of a 2 Ma volcanically-active subduction zone

Propagation of back‐arc extension into the arc lithosphere in the southern New Hebrides volcanic arc

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