Saline aqueous fluid circulation in mantle wedge inferred from olivine wetting properties

Huang, Y. C.; Nakatani, Takayuki; Nakamura, Michihiko; McCammon, Catherine

doi:10.1038/s41467-019-13513-7

Cited by 21 publications

(34 citation statements)

References 78 publications

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“…However, they noted that for the quartz-fluid system, the dihedral angle is drastically reduced upon addition of NaCl, to values as low as 40°. In a more recent study, Huang et al (2019) also observed a reduction of the dihedral angles in the olivine-fluid system to values <60° upon addition of NaCl. In the light of these data, one may plausibly assume that in most crustal lithologies, a HCl and/or NaCl-bearing fluid will likely form an interconnected network and, therefore, strongly enhance bulk conductivity.…”

Section: Remote Sensing Of Magmatic-hydrothermal Systemsmentioning

confidence: 79%

Electrical conductivity of HCl-bearing aqueous fluids to 700 ºC and 1 GPa

Klumbach

Keppler

2020

Contrib Mineral Petrol

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Subsurface magmatic–hydrothermal systems are often associated with elevated electrical conductivities in the Earthʼs crust. To facilitate the interpretation of these data and to allow distinguishing between the effects of silicate melts and fluids, the electrical conductivity of aqueous fluids in the system H2O–HCl was measured in an externally heated diamond anvil cell. Data were collected to 700 °C and 1 GPa, for HCl concentrations equivalent to 0.01, 0.1, and 1 mol/l at ambient conditions. The data, therefore, more than double the pressure range of previous measurements and extend them to geologically realistic HCl concentrations. The conductivities $$\sigma$$ σ (in S/m) are well reproduced by a numerical model log $$\sigma$$ σ = −2.032 + 205.8 T−1 + 0.895 log c + 3.888 log $$\rho$$ ρ + log$$\Lambda_{0}$$ Λ 0 (T,$$\rho$$ ρ ), where T is the temperature in K, c is the HCl concentration in wt. %, and $$\rho$$ ρ is the density of pure water at the corresponding pressure and temperature conditions. $$\Lambda_{0}$$ Λ 0 (T,$$\rho$$ ρ ) is the limiting molar conductivity (in S cm2 mol−1) at infinite dilution, $$\Lambda_{0}$$ Λ 0 (T,$$\rho$$ ρ ) = 2550.14 − 505.10$$\rho$$ ρ − 429,437 T−1. A regression fit of more than 800 data points to this model yielded R2 = 0.95. Conductivities increase with pressure and fluid densities due to an enhanced dissociation of HCl. However, at constant pressures, conductivities decrease with temperature because of reduced dissociation. This effect is particularly strong at shallow crustal pressures of 100–200 MPa and can reduce conductivities by two orders of magnitude. We, therefore, suggest that the low conductivities sometimes observed at shallow depths below the volcanic centers in magmatic–hydrothermal systems may simply reflect elevated temperatures. The strong negative temperature effect on fluid conductivities may offer a possibility for the remote sensing of temperature variations in such systems and may allow distinguishing the effects of magma intrusions from changes in hydrothermal circulation. The generally very high conductivities of HCl–NaCl–H2O fluids at deep crustal pressures (500 MPa–1 GPa) imply that electrical conductors in the deep crust, as in the Altiplano magmatic province and elsewhere, may at least partially be due to hydrothermal activity.

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Section: Remote Sensing Of Magmatic-hydrothermal Systemsmentioning

confidence: 79%

Electrical conductivity of HCl-bearing aqueous fluids to 700 ºC and 1 GPa

Klumbach

Keppler

2020

Contrib Mineral Petrol

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“…They are in contrast to magmatic podiform chromitites, of which silicate matrix is mainly composed of olivine. The fluid possibly redistributes chromium and chromite (or chromian spinel) within the mantle wedge significantly, where saline aqueous fluids are possibly circulating [67]. It can mobilize Pt and Pd in the mantle wedge and crust significantly, although we need more data and information on this subject.…”

Section: Discussionmentioning

confidence: 99%

“…Chlorine and other anions may form complexes with chromium that are soluble in water-rich fluids [21,62,63]. Saline fluids are also expected to be released from the slab to the mantle wedge [64][65][66][67]. If we carefully look peridotite xenoliths derived from the mantle wedge, we frequently observe some textures suggesting accumulation of fine chromite or chromian spinel grains (Figure 14).…”

Section: Origin Of the Fluidmentioning

confidence: 99%

Hydrothermal Chromitites from the Oman Ophiolite: The Role of Water in Chromitite Genesis

Arai

Miura²,

Tamura

et al. 2020

Minerals

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The role of water-rich solutions in the formation of chromitites has been the matter of controversy. We found small chromite concentrations (chromitites) in diopsidites, precipitated from high-temperature hydrothermal fluids, in the mantle to the crust of the Oman ophiolite. Here, we present petrologic characteristics of the hydrothermal chromitites to understand their genesis. In the chromitites, the chromite is associated with uvarovite in the crust and diopside + grossular in the mantle. They are discriminated from the magmatic podiform chromitite by dominance of the Ca-Al silicates in the matrix. The fluids responsible for chromite precipitation are possibly saline, being derived from the seawater circulated into the mantle through the crust. The saline fluids precipitate chromite to form chromite upon decompression and cooling, and transport platinum-group elements (especially Pt and Pd). The fluids obtain Ca and Al from the crustal rocks and Cr from the mantle rocks during circulation. Saline fluids are also supplied from the slab to the mantle wedge, and can metasomatically precipitate chromite and pyroxenes within peridotites. They re-distribute Cr and chromite in peridotites along with circulation of saline fluids in the mantle wedge.

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“…In hot subduction zones, such as Cascadia and Mexico, fluids liberated from the shallow subducting slabs at depths of 30-60 km can penetrate through the highly serpentinized mantle wedge and accumulate in the deep fore-arc region (Nakatani & Nakamura, 2016;Reynard et al, 2011). In intermediate and cold subduction zones, in contrast, saline fluid liberated at a depth of ∼80 km can penetrate all the way through the fore-arc mantle wedge without mantle melting and serpentinization due to low dihedral angles (Huang et al, 2019). Therefore, our experimental results can be applied to MT data of intermediate and cold subduction zones where the slab-derived saline fluids can be present in the non-serpentinized fore-arc mantle.…”

Section: Implication: Estimation Of Fluid Fractions In Fore-arc Mantle Wedgesmentioning

confidence: 99%

“…Recently, a growing number of MT observations have revealed high electrical conductivity anomalies (0.001-1 S/m) in the deep fore-arc crust and mantle wedge in some subduction zones (e.g., Araya Vargas et al, 2019;Pommier & Evans, 2017;Worzewski et al, 2011). Because the temperature is relatively low in fore-arc regions (<700-800°C, Syracuse et al, 2010), aqueous fluid rather than silicate melt has been assumed to be the highly conductive phase present in the lower crust and mantle wedge, supplied by the subducting slab through a permeable window in the fore-arc mantle wedge (Huang et al, 2019). Although conductive minerals such as sulfide (Ducea & Park, 2000), graphite (Frost et al, 1989;Glover, 1996), and magnetite (Manthilake et al, 2016) have also been suggested to be the cause of the observed high electrical conductivity, their volume fraction may not be sufficiently high to form interconnected networks in rocks.…”

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confidence: 99%

Electrical conductivity in texturally equilibrated fluid-bearing forsterite aggregates at 800 ºC and 1 GPa: implications for the high electrical conductivity anomalies in mantle wedges

Huang

Guo

Nakatani

et al. 2020

Preprint

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In subduction zones, aqueous fluids released from the subducting slab percolate through the mantle wedge, controlling arc magma genesis, and element recycling (e.g., Hermann et al., 2006;Iwamori, 1998;Tatsumi, 1986;van Keken et al., 2011). Although the pore fluid preserved in the subducting oceanic lithosphere will be expelled by compaction at relatively shallow depth, hydrous minerals may effectively carry water deep into the mantle and release it through dehydration reactions upon progressive metamorphism. Because the presence of fluid significantly enhances the bulk electrical conductivity of rocks (e.g., X.

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Saline aqueous fluid circulation in mantle wedge inferred from olivine wetting properties

Cited by 21 publications

References 78 publications

Electrical conductivity of HCl-bearing aqueous fluids to 700 ºC and 1 GPa

Electrical conductivity of HCl-bearing aqueous fluids to 700 ºC and 1 GPa

Hydrothermal Chromitites from the Oman Ophiolite: The Role of Water in Chromitite Genesis

Electrical conductivity in texturally equilibrated fluid-bearing forsterite aggregates at 800 ºC and 1 GPa: implications for the high electrical conductivity anomalies in mantle wedges

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Saline aqueous fluid circulation in mantle wedge inferred from olivine wetting properties

Cited by 21 publications

References 78 publications

Electrical conductivity of HCl-bearing aqueous fluids to 700 ºC and 1 GPa

Electrical conductivity of HCl-bearing aqueous fluids to 700 ºC and 1 GPa

Hydrothermal Chromitites from the Oman Ophiolite: The Role of Water in Chromitite Genesis

Electrical conductivity in texturally equilibrated fluid-bearing forsterite aggregates at 800 &ordm;C and 1 GPa: implications for the high electrical conductivity anomalies in mantle wedges

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Electrical conductivity in texturally equilibrated fluid-bearing forsterite aggregates at 800 ºC and 1 GPa: implications for the high electrical conductivity anomalies in mantle wedges