An improved experimental calibration of the olivine-spinel geothermometer

Li, Jianping; Kornprobst, Jacques; Vielzeuf, Daniel; Fabriès, Jacques

doi:10.1007/bf02840385

Cited by 63 publications

(28 citation statements)

References 19 publications

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“…This temperature estimate is consistent with the high-temperature microstructures and inferred deformation mechanisms of the Fresno Bench shear zones (Kumamoto et al, in revision;Nevitt et al, 2019;Skemer et al, 2010Skemer et al, , 2013Warren et al, 2008). The lower temperature range (900°C ± 26°C) given by the olivine-spinel thermometer (Li et al, 1995) is also consistent with these processes. Finally, these temperatures are consistent with melt-rock interaction and hydration by melt as discussed in the previous section.…”

Section: Geothermometrysupporting

confidence: 87%

“…In the nearly clinopyroxene-free rocks of the Fresno Bench outcrop, few thermometers are available. We calculate temperatures for our shear zone transects ( Figure S2) in two ways using our major element data: the Al/Cr-in-orthopyroxene thermometer of Witt-Eickschen and Seck (1991) and the olivine-spinel thermometer of Li et al (1995). Both of these thermometers are based on the closure temperatures of major element diffusion in their host mineral(s).…”

Section: Geothermometrymentioning

confidence: 99%

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Evolution of the Josephine Peridotite Shear Zones: 1. Compositional Variation and Shear Initiation

Kumamoto

Warren

Hauri

2019

Geochem Geophys Geosyst

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Shear localization in the upper mantle, a necessity for plate tectonics, can have a number of causes, including shear heating, the presence of melt, the development of a strong crystal preferred orientation, and the presence of water. The Josephine Peridotite of southwestern Oregon contains shear zones that provide an excellent opportunity to examine the initiation of shear localization. These shear zones are relatively small scale and low strain compared to many shear zones in peridotite massifs, which typically have extreme grain size reduction indicating extensive deformation. We use major, trace, and volatile element analyses of a large suite of harzburgites from the Fresno Bench shear zones to evaluate the mechanisms leading to shear localization. Lithological evidence and geochemical transects across three shear zones show a complex history of melting, melt addition, and melt‐rock interaction. The distribution of aluminum and heavy rare earth elements across the shear zones suggest that melt flow was focused in the centers of the studied shear zones. Water concentrations in orthopyroxene grains of 180–334 ppm H2O indicate a comparatively high degree of hydration for nominally anhydrous minerals. The correlation of water with aluminum and ytterbium in orthopyroxene is consistent with a melt source for this hydration, suggesting that water equilibrated between the melt and peridotite. The presence of melt and hydration of the host rock provide mechanisms for initial weakening that lead to localized deformation.

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Section: Geothermometrysupporting

confidence: 87%

Section: Geothermometrymentioning

confidence: 99%

Evolution of the Josephine Peridotite Shear Zones: 1. Compositional Variation and Shear Initiation

Kumamoto

Warren

Hauri

2019

Geochem Geophys Geosyst

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“…For calculations, we applied four geothermometers based on major-element mineral compositions measured by microprobe (see Supplementary Tables 1–6 ). These geothermometers include the Ca-in-OPx thermometer 65 , Al/Cr-in-OPx thermometer 66 , two-pyroxenes thermometer 65 (BKN) and olivine-spinel thermometer 67 . The horizontal lines link the two different grain sizes in the case of the two-phase thermometers.…”

Section: Figurementioning

confidence: 99%

Water pumping in mantle shear zones

et al. 2017

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Water plays an important role in geological processes. Providing constraints on what may influence the distribution of aqueous fluids is thus crucial to understanding how water impacts Earth's geodynamics. Here we demonstrate that ductile flow exerts a dynamic control on water-rich fluid circulation in mantle shear zones. Based on amphibole distribution and using dislocation slip-systems as a proxy for syn-tectonic water content in olivine, we highlight fluid accumulation around fine-grained layers dominated by grain-size-sensitive creep. This fluid aggregation correlates with dislocation creep-accommodated strain that localizes in water-rich layers. We also give evidence of cracking induced by fluid pressure where the highest amount of water is expected. These results emphasize long-term fluid pumping attributed to creep cavitation and associated phase nucleation during grain size reduction. Considering the ubiquitous process of grain size reduction during strain localization, our findings shed light on multiple fluid reservoirs in the crust and mantle.

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“…Therefore caution must be exercised when inferring magmatic history from these subsolidus samples. Subsolidus temperatures for our Josephine and Trinity samples were calculated using the twopyroxene geothermometer of Brey and and a revised olivine-spinel geothermometer of Fabries [1979;Liu et al, 1995]. For each sample we independently measured approximately 10 compositions of each mineral, olivine, spinel, opx and cpx in a thin section or a 25.4 mm diameter drill core mount.…”

Section: Subsolidus Reequilibrationmentioning

confidence: 99%

Significance of the concentration gradients associated with dunite bodies in the Josephine and Trinity ophiolites

Morgan

Liang

Kelemen

2008

Geochem Geophys Geosyst

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[1] Detailed transects were sampled across dunite bodies in the Josephine and Trinity ophiolites. The major peridotite lithologies sampled in the Josephine transect are a sequence of dunite and harzburgite and in the Trinity transect a sequence of dunite, harzburgite, lherzolite, and plagioclase lherzolite (DHL-PL). Major, minor, and selected trace element abundances in olivine, orthopyroxene, clinopyroxene, and spinel were measured. The composition profile from the Josephine transect has revealed a concentration gradient near the dunite-harzburgite contact. The composition profile from the Trinity transect has revealed several concentration gradients: two within the dunite, one in the harzburgite, and at least two in the plagioclase lherzolite. The composition profiles record complex histories of melt transport, melt-rock reaction, and subsequent subsolidus reequilibration. Analyses of closure distance suggest that compositional variation trends for a majority of major and minor elements in olivine, clinopyroxene, orthopyroxene, and spinel reported in this study were magmatic in origin. Subsolidus reequilibration may reduce the range or magnitude of variations for the 2+ cations such as Fe and Mg in olivine and spinel and significantly redistribute Ca and Li in coexisting minerals. Numerical simulations exploring the coupling of diffusion and advection in a porous matrix were used to explain compositional variations across the peridotite sequences. Melt flow from the host harzburgite into the dunite produces composition gradients near the dunite-harzburgite contacts similar to those from the Josephine transect. In contrast, melt flow from the dunite into the surrounding peridotite lithologies can produce concentration gradients similar to those observed in the Trinity transect. At least two chemically distinct episodes of melt flow within the same dunite channel system are proposed. Results from this study show that concentration gradients developed around the dunite-harzburgite and DHL-PL sequences can be used to infer part of the melt flow history of the dunite channel systems in the mantle. Results from this study and those from other ophiolite studies also demonstrate that concentration profiles in dunite and the surrounding peridotite lithologies are highly variable even among differing peridotite sequences within the same ophiolite, suggesting that the composition of instantaneous melt flowing through individual dunite channels is quite variable and the mantle source regions are heterogeneous.

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An improved experimental calibration of the olivine-spinel geothermometer

Cited by 63 publications

References 19 publications

Evolution of the Josephine Peridotite Shear Zones: 1. Compositional Variation and Shear Initiation

Evolution of the Josephine Peridotite Shear Zones: 1. Compositional Variation and Shear Initiation

Water pumping in mantle shear zones

Significance of the concentration gradients associated with dunite bodies in the Josephine and Trinity ophiolites

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