Fluorine in nominally fluorine-free mantle minerals: Experimental partitioning of F between olivine, orthopyroxene and silicate melts with implications for magmatic processes

Beyer, Christopher; Klemme, Stephan; Wiedenbeck, Michael; Stracke, Andreas; Vollmer, C.

doi:10.1016/j.epsl.2012.05.003

Cited by 95 publications

(70 citation statements)

References 63 publications

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“…The D ol=melt F value (0.116) of was dismissed because it is two orders of magnitude higher than that reported by Beyer et al (2012) at similar P-T conditions in the CMASF (CaO, MgO, Al 2 O 3 , SiO 2 , and F) and NCMASF (Na 2 O, CaO, MgO, Al 2 O 3 , SiO 2 , and F) systems and by Hauri et al (2006) in basaltic and basanitic systems. The discrepancy between these data is perhaps due to the presence of micro-inclusions, clinohumite lamellae, or clumped OH/F defects (Crépisson et al 2014) in the high F olivine ).…”

Section: F and CL Partition Coefficients For Hydrous Experimentsmentioning

confidence: 88%

“…Instead, it is suggested that F enrichment is most likely achieved by the percolation of silicate melts (Wu and Koga 2013). Experimentally determined F partition coefficients between mantle minerals (olivine, pyroxenes, and garnet) and anhydrous silicate melts (Beyer et al 2012;) allow the calculation of F content in melts produced by simple batch melting of an anhydrous lherzolite (with F =16 ppm, Saal et al 2002). The addition of those calculated anhydrous silicate melts (maximum F content approximately 400 ppm) into the mantle wedge does not generate high F content arc magmas (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Contrasting partition behavior of F and Cl during hydrous mantle melting: implications for Cl/F signature in arc magmas

Dalou

Koga

Voyer

et al. 2014

Prog. in Earth and Planet. Sci.

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We present the results of five experiments on F and Cl partitioning during hydrous mantle melting under conditions relevant to subduction zone magmatism (1.2-2.5 GPa, 1,180°C-1,430°C). For each experiment, we determined the F and Cl partition coefficients between lherzolitic mineral phases (olivine, orthopyroxene (opx), clinopyroxene (cpx), and garnet), amphibole, and hydrous basaltic melts (0.2-5.9 wt.% dissolved H 2 O). At constant pressure, D increases from 0.009 ± 0.0005 to 0.015 ± 0.0008. Experimentally determined F and Cl partition coefficients were used in a hydrous melting model of a lherzolitic mantle metasomatized by slab fluid. In this model, we vary the amount of metasomatic slab fluid added into the mantle while its composition is kept constant. Increasing the amount of fluid results in an increase of both the degree of melting (due to the effect of H 2 O addition) and the F and Cl input in the mantle wedge. Because of the change of F and Cl partition coefficients with the increase of H 2 O, the observed variation in the F and Cl contents of the modeled melts is produced not only by F and Cl input from the fluid, but also by the changes in F and Cl fractionation during hydrous melting. Overall, the model predicts that the Cl/F ratio of modeled melts increases with increasing fluid fraction. Therefore, a variation in the amount of fluid added to the mantle wedge can contribute to the variability in Cl/F ratios observed in arc melt inclusions.

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Section: F and CL Partition Coefficients For Hydrous Experimentsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Contrasting partition behavior of F and Cl during hydrous mantle melting: implications for Cl/F signature in arc magmas

Dalou

Koga

Voyer

et al. 2014

Prog. in Earth and Planet. Sci.

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“…From the lithophile behavior of F (McDonough and Sun, 1995) and based on previous studies (Beyer et al, 2012), it has been proposed that nominally anhydrous silicate phases (such as olivine and pyroxene Px) might accommodate the bulk F content of the whole upper mantle in regards to their high modal proportion in the mantle. However, the F contents measured in upper mantle natural Ol and Px are <100 ppm (Hervig and Bell, 2005;Beyer et al, 2012;Rossman, 2013a, 2013b).…”

Section: Fluorine In the Transition Zonementioning

confidence: 99%

“…By comparison, experimental studies performed to determine fluorine solubility in these major mantle mineral phases yielded maximum contents of fluorine of 4500 ppm to 1900 ppm in olivine (Bromiley and Kohn, 2007;Bernini et al, 2012), 626 ppm in pyroxenes (Dalou et al, 2012), and 1110 ppm in pyrope (Bernini et al, 2012). Like water, that is stored in silicate minerals as hydroxyl species, it has been proposed that the mantle fluorine budget can be entirely accommodated by these mineral phases (Beyer et al, 2012;Crépisson et al, 2014). Based on the observation of clumped fluoride-hydroxyl defects in pure-Mg olivine, the major upper mantle mineral, it is likely that fluorine and water cycles may be strongly coupled through the nominally anhydrous minerals (Crépisson et al, 2014).…”

Section: Introductionmentioning

confidence: 97%

“…For these reasons it seems necessary to determine how F is stored within potential reservoirs of the mantle, and to consider whether the fluorine content in the BSE may have been over or underestimated. Therefore in an attempt to put constrains on the fluorine content in the upper mantle, fluorine concentrations have recently been measured in nominally anhydrous mantle minerals (Beyer et al, 2012;Rossman, 2013a, 2013b). These studies have demonstrated that up to 47 ppm of fluorine can be incorporated in natural olivine and pyroxene.…”

Section: Introductionmentioning

confidence: 99%

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Is the transition zone a deep reservoir for fluorine?

Roberge

Bureau

Bolfan-Casanova

et al. 2015

Earth and Planetary Science Letters

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International audienceIt is now recognized that the transition zone (TZ) is a significant repository for water. This means that other volatile species may also be stored in this region such as halogen elements. We have measured the solubility of fluorine in wadsleyite (Wd) and ringwoodite (Rw) under hydrous and anhydrous conditions at different pressures and temperatures, relevant for the transition zone. F contents are similar in Wd (665 to 1045 ppm F, up to 956 ppm H2O) and in Rw (186 to 1235 ppm F, up to 1404 ppm H2O). This suggests that F may be incorporated in the same manner as water in the major nominally anhydrous minerals of the TZ: ringwoodite and wadsleyite and that the transition zone could be a major reservoir for fluorine. In the framework of the “water filter model” proposed by Bercovici and Karato (2003), the contrast of volatile element contents between a depleted upper mantle and an enriched transition zone could be maintained over geological time scales. Previous estimates of the fluorine content of the Bulk Silicate Earth (BSE), such as 25 ppm by mass (McDonough and Sun, 1995), have assumed a homogeneous mantle. Although we do not know whether the TZ is F saturated or not, we used our new experimental data and estimates of the lower mantle F content from ocean island basalts to estimate a maximum BSE fluorine content of 59 ppm by mass for a hydrous, F-saturated TZ. This upper bound on the range of possible BSE F content emphasizes the challenges when explaining the origin of volatile elements in the Earth from a carbonaceous chondrite late veneer

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Pyroxenes as tracers of mantle water variations

2014

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The concentration and distribution of volatiles in the Earth's mantle influence properties such as melting temperature, conductivity, and viscosity. To constrain upper mantle water content, concentrations of H 2 O, P, and F were measured in olivine, orthopyroxene, and clinopyroxene in mantle peridotites by secondary ion mass spectrometry. Analyzed peridotites are xenoliths (Pali Aike, Spitsbergen, Samoa), orogenic peridotites (Josephine Peridotite), and abyssal peridotites (Gakkel Ridge, Southwest Indian Ridge, Tonga Trench). The comparison of fresh and altered peridotites demonstrates that low to moderate levels of alteration do not affect H 2 O concentrations, in agreement with mineral diffusion data. Olivines have diffusively lost water during emplacement, as demonstrated by disequilibrium between olivine and coexisting pyroxenes. In contrast, clinopyroxene and orthopyroxene preserve their high-temperature water contents, and their partitioning agrees with published experiments and other xenoliths. Hence, olivine water concentrations can be determined from pyroxene concentrations using mineral-mineral partition coefficients. Clinopyroxenes have 60-670 ppm H 2 O, while orthopyroxenes have 10-300 ppm, which gives calculated olivine concentrations of 8-34 ppm. The highest olivine water concentration translates to an effective viscosity of 6 × 1019 Pa s at 1250°C and~15 km depth, compared to a dry effective viscosity of 2.5 × 10 21 Pa s. Bulk rock water concentrations, calculated using mineral modes, are 20-220 ppm and correlate with peridotite indices of melt depletion. However, trace element melt modeling indicates that peridotites have too much water relative to their rare earth element concentrations, which may be explained by late-stage melt addition, during which only hydrogen diffuses fast enough for reequilibration.

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Fluorine in nominally fluorine-free mantle minerals: Experimental partitioning of F between olivine, orthopyroxene and silicate melts with implications for magmatic processes

Cited by 95 publications

References 63 publications

Contrasting partition behavior of F and Cl during hydrous mantle melting: implications for Cl/F signature in arc magmas

Contrasting partition behavior of F and Cl during hydrous mantle melting: implications for Cl/F signature in arc magmas

Is the transition zone a deep reservoir for fluorine?

Pyroxenes as tracers of mantle water variations

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