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1c5c32b11b5ad1bd9c846a77784abc38 |
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Creator |
51ba1648465fe8c369f2825dd9ca5ad7 |
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Creator |
b75227dc49245aab76a534b836099ab7 |
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Creator |
5011773fcf23f000f9342da951f8316f |
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Creator |
ext-085d7fc1dadf130eb948d28f9b6de0ff |
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Creator |
ext-53ecc87ad78187e381b82b358982d06d |
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Creator |
ext-6911d2d0f44c394743105ab5f10324b0 |
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Creator |
ext-8fac57dfe889a52fbf0a000b5dfd36f7 |
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Creator |
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Creator |
ext-b2dee634b577c519d2548afaeb343fa7 |
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Creator |
ext-eb49b5668f1712166f12f9ba032e5832 |
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Date |
2015-08-01 |
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Is Part Of |
repository |
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Is Part Of |
p0003004X |
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abstract |
Apatite-melt partitioning experiments were conducted in a piston-cylinder press at
1.0–1.2 GPa and 950–1000 °C using an Fe-rich basaltic starting composition and an
oxygen fugacity within the range of ΔIW-1 to ΔIW+2. Each experiment had a unique F:Cl:OH
ratio to assess the partitioning as a function of the volatile content of apatite
and melt. The quenched melt and apatite were analyzed by electron probe microanalysis
and secondary ion mass spectrometry techniques. The mineral-melt partition coefficients
(<i>D</i> values) determined in this study are as follows: <i>D</i><sub>F</sub><sup>Ap-Melt</sup>
= 4.4–19, <i>D</i><sub>Cl</sub><sup>Ap-Melt</sup> = 1.1–5, <i>D</i><sub>OH</sub><sup>Ap-Melt</sup>
= 0.07–0.24. This large range in values indicates that a linear relationship does
not exist between the concentrations of F, Cl, or OH in apatite and F, Cl, or OH in
melt, respectively. This non-Nernstian behavior is a direct consequence of F, Cl,
and OH being essential structural constituents in apatite and minor to trace components
in the melt. Therefore mineral-melt <i>D</i> values for F, Cl, and OH in apatite should
not be used to directly determine the volatile abundances of coexisting silicate melts.
However, the apatite-melt <i>D</i> values for F, Cl, and OH are necessarily interdependent
given that F, Cl, and OH all mix on the same crystallographic site in apatite. Consequently,
we examined the ratio of <i>D</i> values (exchange coefficients) for each volatile
pair (OH-F, Cl-F, and OH-Cl) and observed that they display much less variability:
<i>K</i><sub>d<sub>Cl-F</sub></sub><sup>Ap-Melt</sup>=0.21±0.03, <i>K</i><sub>d<sub>OH-F</sub></sub><sup>Ap-Melt</sup>=0.014±0.002,
and <i>K</i><sub>d<sub>OH-Cl</sub></sub><sup>Ap-Melt</sup>=0.06±0.02. However, variations
with apatite composition, specifically when mole fractions of F in the apatite X-site
were low (<i>X</i><sub>F</sub> < 0.18), were observed and warrant additional study.
To implement the exchange coefficient to determine the H<sub>2</sub>O content of a
silicate melt at the time of apatite crystallization (apatite-based melt hygrometry),
the H<sub>2</sub>O abundance of the apatite, an apatite-melt exchange <i>K</i>d that
includes OH (either OH-F or OH-Cl), and the abundance of F or Cl in the apatite and
F or Cl in the melt at the time of apatite crystallization are needed (F if using
the OH-F <i>K</i><sub>d</sub> and Cl if using the OH-Cl <i>K</i><sub>d</sub>). To
determine the H<sub>2</sub>O content of the parental melt, the F or Cl abundance of
the parental melt is needed in place of the F or Cl abundance of the melt at the time
of apatite crystallization. Importantly, however, exchange coefficients may vary as
a function of temperature, pressure, melt composition, apatite composition, and/or
oxygen fugacity, so the combined effects of these parameters must be investigated
further before exchange coefficients are applied broadly to determine volatile abundances
of coexisting melt from apatite volatile abundances. |
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authorList |
authors |
| 45141 |
issue |
8-9 |
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status |
peerReviewed |
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volume |
100 |
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type |
AcademicArticle |
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type |
Article |
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label |
McCubbin, Francis M.; Vander Kaaden, Kathleen E.; Tartèse, Romain ; Boyce, Jeremy
W.; Mikhail, Sami ; Whitson, Eric S.; Bell, Aaron S.; Anand, Mahesh ; Franchi, Ian
A. ; Wang, Jianhua and Hauri, Erik H. (2015). Experimental investigation of F, Cl,
and OH partitioning between apatite and Fe-rich basaltic melt at 1.0–1.2 GPa and 950–1000
°C. American Mineralogist, 100(8-9) pp. 1790–1802. |
| 45141 |
label |
McCubbin, Francis M.; Vander Kaaden, Kathleen E.; Tartèse, Romain ; Boyce, Jeremy
W.; Mikhail, Sami ; Whitson, Eric S.; Bell, Aaron S.; Anand, Mahesh ; Franchi, Ian
A. ; Wang, Jianhua and Hauri, Erik H. (2015). Experimental investigation of F, Cl,
and OH partitioning between apatite and Fe-rich basaltic melt at 1.0–1.2 GPa and 950–1000
°C. American Mineralogist, 100(8-9) pp. 1790–1802. |
| 45141 |
Title |
Experimental investigation of F, Cl, and OH partitioning between apatite and Fe-rich
basaltic melt at 1.0–1.2 GPa and 950–1000 °C |
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in dataset |
oro |