Hydrogen partitioning between melt, clinopyroxene, and garnet at 3 GPa in a hydrous MORB with 6 wt.% H2O

Aubaud, Cyril; Hirschmann, M. M.; Withers, A. C.; Hervig, R. L.

doi:10.1007/s00410-008-0304-2

Cited by 65 publications

(46 citation statements)

References 68 publications

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“…In eastern NCC, the variation of petrochemistry of Cenozoic basalts was related to the temporal change in lithospheric thickness, and tholeiitic basalts from convection mantle were thought to be the signals of the thinnest is commonly C0.02, but \0.04 at pressure of 3.0 GPa (Aubaud et al 2008), the melting curves of both D bulk \0.01 and D bulk [0.04 are not shown here. The number labeled on the melting curves represents the water content in the source.…”

Section: Implications For the Lithospheric Evolution In Eastern Nccmentioning

confidence: 89%

Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

Zhang

Qian

et al. 2012

Contrib Mineral Petrol

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The geochemical characteristics of melt inclusions and their host olivines provide important information on the processes that create magmas and the nature of their mantle and crustal source regions. We report chemical compositions of melt inclusions, their host olivines and bulk rocks of Xindian basalts in Chifeng area, North China Craton. Compositions of both bulk rocks and melt inclusions are tholeiitic. Based on petrographic observations and compositional variation of melt inclusions, the crystallizing sequence of Xindian basalts is as follows: olivine (at MgO [ *5.5 wt%), plagioclase (beginning at MgO = *5.5 wt%), clinopyroxene and ilmenite (at MgO \ 5.0 wt%). High Ni contents and Fe/Mn ratios, and low Ca and Mn contents in olivine phenocrysts, combining with low CaO contents of relatively high MgO melt inclusions (MgO [ 6 wt%), indicate that Xindian basalts are possibly derived from a pyroxenite source rather than a peridotite source. In the CS-MS-A diagram, all the high MgO melt inclusions (MgO [ 6.0 wt%) project in the field between garnet ? clinopyroxene ? liquid and garnet ? clinopyroxene ? orthopyroxene ? liquid near 3.0 GPa, further suggesting that residual minerals are mainly garnet and clinopyroxene, with possible presence of orthopyroxene, but without olivine. Modeling calculations using MELTS show that the water content of Xindian basalts is 0.3-0.7 wt% at MgO = 8.13 wt%. Using 20-25 % of partial melting estimated by moderately incompatible element ratios, the water content in the source of Xindian basalts is inferred to be C450 ppm, much higher than 6-85 ppm in dry lithospheric mantle. The melting depth is inferred to be *3.0 GPa, much deeper than that of tholeiitic lavas (\2.0 GPa), assuming a peridotite source with a normal mantle potential temperature. Such melting depth is virtually equal to the thickness of lithosphere beneath Chifeng area (*100 km), suggesting that Xindian basalts are derived from the asthenospheric mantle, if the lithospheric lid effect model is assumed.

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Section: Implications For the Lithospheric Evolution In Eastern Nccmentioning

confidence: 89%

Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

Zhang

Qian

et al. 2012

Contrib Mineral Petrol

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“…In this model, the melt fraction depends on the water fraction, temperature, and pressure, but not on the degree of mantle depletion (i.e., major element composition) due to melt extraction, and this assumption is likely to result in an overestimate for the amount of produced melt; the validity of this will therefore be examined later. Water partitioning between solid and melt is assumed to reach equilibrium instantaneously, with a constant partition coefficient of 0.01 (Aubaud et al 2008;Kohn and Grant 2006). The energy transported by the aqueous fluid and energy for phase transformation related to hydration and dehydration are neglected.…”

Section: Modelmentioning

confidence: 99%

Numerical modeling of trace element transportation in subduction zones: implications for geofluid processes

Ikemoto

Iwamori

2014

Earth, Planets and Space

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This study presents the first numerical model for trace element transportation associated with dehydration and fluid migration from the subducting slab and aims to incorporate both fluid dynamical processes (e.g., flow mode and mass fluxes) in subduction zones and associated geochemical evidence (e.g., chemical compositions of arc lavas). The model includes temperature and flow structures associated with slab subduction and mantle-fluid two-phase flow, as well as phase relations of hydrous phases (e.g., dehydration-hydration reactions and melting) and trace element partitioning among the phases (solid, aqueous fluid, and melt). The model calculations show that if instantaneous chemical equilibrium is achieved associated with porous flow of slab-derived fluid, the elements expelled with the ascending fluid (e.g., Pb) are absorbed into the down-going hydrated mantle layer developed above the slab. As a result, these elements are considerably depleted in the resultant magma generated by fluidflux melting in the core part of the mantle wedge, and it therefore fails to reproduce the geochemical characteristics of arc lavas. In contrast, if disequilibrium element transport (e.g., associated with channel flow) is assumed when the hydrated mantle layer liberates the fluid, then the key elements are delivered to the melting region to reproduce certain arc lava signatures. These results suggest that disequilibrium fluid transport in the wedge mantle, such as through channels, plays an important role in element cycling in subduction zones.

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“…This results mainly from the preferential partitioning of H 2 O into the melt phase over NAMs in (residual) eclogite124. As these hydrous melts react with enclosing peridotite, H 2 O will be in part be incorporated into NAMs in the newly formed orthopyroxene-rich RZLs.…”

mentioning

confidence: 99%

Continuous eclogite melting and variable refertilisation in upwelling heterogeneous mantle

Rosenthal

Yaxley

Green

et al. 2014

Sci Rep

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Large-scale tectonic processes introduce a range of crustal lithologies into the Earth's mantle. These lithologies have been implicated as sources of compositional heterogeneity in mantle-derived magmas. The model being explored here assumes the presence of widely dispersed fragments of residual eclogite (derived from recycled oceanic crust), stretched and stirred by convection in the mantle. Here we show with an experimental study that these residual eclogites continuously melt during upwelling of such heterogeneous mantle and we characterize the melting reactions and compositional changes in the residue minerals. The chemical exchange between these partial melts and more refractory peridotite leads to a variably metasomatised mantle. Re-melting of these metasomatised peridotite lithologies at given pressures and temperatures results in diverse melt compositions, which may contribute to the observed heterogeneity of oceanic basalt suites. We also show that heterogeneous upwelling mantle is subject to diverse local freezing, hybridization and carbonate-carbon-silicate redox reactions along a mantle adiabat.

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Hydrogen partitioning between melt, clinopyroxene, and garnet at 3 GPa in a hydrous MORB with 6 wt.% H2O

Cited by 65 publications

References 68 publications

Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

Numerical modeling of trace element transportation in subduction zones: implications for geofluid processes

Continuous eclogite melting and variable refertilisation in upwelling heterogeneous mantle

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