An experimental study of water in nominally anhydrous minerals in the upper mantle near the water-saturated solidus

I. Kovács, David H. Green, Anja Rosenthal, Jörg Hermann, Hugh St C O'neill, William O. Hibberson, Beatrix Udvardi

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

The incorporation of water in olivine and pyroxenes interlayered within fertile lherzolite compositions was explored experimentally near the wet solidus of lherzolite at 2·5 and 4 GPa. The concentrations and activities of water were varied to establish the partitioning of water between nominally anhydrous minerals (NAMs) and the hydrous minerals pargasite and phlogopite. The water content in NAMs was determined by Fourier-transform infrared (FTIR) spectroscopy. The main absorption bands in NAMs from these experiments are very similar to those generally found in natural upper mantle peridotites. Olivine, orthopyroxene and clinopyroxene contain 32-190, 290-320 and 910-980 ppm of water under the studied conditions. The partition coefficients between coexisting clinopyroxene and orthopyroxene (D cpx/opx) are 2·7 ± 1·1 and 3·5 ± 1·5 at 2·5 and 4 GPa respectively, whereas values for coexisting orthopyroxene and olivine (D opx/ol) are 6·7 ± 2 and 4·7 ± 1·1, at 2·5 and 4 GPa respectively. The storage capacity in NAMs in a model mantle composition close to the vapour-saturated solidus (water-rich vapour) is ∼190 ppm at both 2·5 and 4 GPa. Pargasite is the most important phase accommodating significant amounts of water in the uppermost mantle. Its breakdown with increasing pressure at 3 GPa at the vapour-saturated solidus (which is at ∼1025°C at 2·5 GPa) results in a sharp drop in the water storage capacity of peridotite from ∼1000 ppm to ∼190 ppm H 2O. At pressures >3 GPa, melting in fertile lherzolite begins at the vapour-saturated solidus if the bulk H 2O concentration exceeds ∼190 ppm.

Original languageEnglish
Article numberegs044
Pages (from-to)2067-2093
Number of pages27
JournalJournal of Petrology
Volume53
Issue number10
DOIs
Publication statusPublished - Oct 2012

Fingerprint

solidus
Minerals
upper mantle
Earth mantle
experimental study
minerals
lherzolite
orthopyroxene
Water
pargasite
mineral
olivine
water
Vapors
clinopyroxene
vapors
mantle
hydrous mineral
phlogopite
pyroxenes

Keywords

  • Infrared spectroscopy
  • Nominally anhydrous minerals
  • Pargasite
  • Partial melting
  • Phlogopite
  • Upper mantle
  • Water

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Kovács, I., Green, D. H., Rosenthal, A., Hermann, J., O'neill, H. S. C., Hibberson, W. O., & Udvardi, B. (2012). An experimental study of water in nominally anhydrous minerals in the upper mantle near the water-saturated solidus. Journal of Petrology, 53(10), 2067-2093. [egs044]. https://doi.org/10.1093/petrology/egs044

An experimental study of water in nominally anhydrous minerals in the upper mantle near the water-saturated solidus. / Kovács, I.; Green, David H.; Rosenthal, Anja; Hermann, Jörg; O'neill, Hugh St C; Hibberson, William O.; Udvardi, Beatrix.

In: Journal of Petrology, Vol. 53, No. 10, egs044, 10.2012, p. 2067-2093.

Research output: Contribution to journalArticle

Kovács, I, Green, DH, Rosenthal, A, Hermann, J, O'neill, HSC, Hibberson, WO & Udvardi, B 2012, 'An experimental study of water in nominally anhydrous minerals in the upper mantle near the water-saturated solidus', Journal of Petrology, vol. 53, no. 10, egs044, pp. 2067-2093. https://doi.org/10.1093/petrology/egs044
Kovács, I. ; Green, David H. ; Rosenthal, Anja ; Hermann, Jörg ; O'neill, Hugh St C ; Hibberson, William O. ; Udvardi, Beatrix. / An experimental study of water in nominally anhydrous minerals in the upper mantle near the water-saturated solidus. In: Journal of Petrology. 2012 ; Vol. 53, No. 10. pp. 2067-2093.
@article{677483e842f64a18a8f02188b0926944,
title = "An experimental study of water in nominally anhydrous minerals in the upper mantle near the water-saturated solidus",
abstract = "The incorporation of water in olivine and pyroxenes interlayered within fertile lherzolite compositions was explored experimentally near the wet solidus of lherzolite at 2·5 and 4 GPa. The concentrations and activities of water were varied to establish the partitioning of water between nominally anhydrous minerals (NAMs) and the hydrous minerals pargasite and phlogopite. The water content in NAMs was determined by Fourier-transform infrared (FTIR) spectroscopy. The main absorption bands in NAMs from these experiments are very similar to those generally found in natural upper mantle peridotites. Olivine, orthopyroxene and clinopyroxene contain 32-190, 290-320 and 910-980 ppm of water under the studied conditions. The partition coefficients between coexisting clinopyroxene and orthopyroxene (D cpx/opx) are 2·7 ± 1·1 and 3·5 ± 1·5 at 2·5 and 4 GPa respectively, whereas values for coexisting orthopyroxene and olivine (D opx/ol) are 6·7 ± 2 and 4·7 ± 1·1, at 2·5 and 4 GPa respectively. The storage capacity in NAMs in a model mantle composition close to the vapour-saturated solidus (water-rich vapour) is ∼190 ppm at both 2·5 and 4 GPa. Pargasite is the most important phase accommodating significant amounts of water in the uppermost mantle. Its breakdown with increasing pressure at 3 GPa at the vapour-saturated solidus (which is at ∼1025°C at 2·5 GPa) results in a sharp drop in the water storage capacity of peridotite from ∼1000 ppm to ∼190 ppm H 2O. At pressures >3 GPa, melting in fertile lherzolite begins at the vapour-saturated solidus if the bulk H 2O concentration exceeds ∼190 ppm.",
keywords = "Infrared spectroscopy, Nominally anhydrous minerals, Pargasite, Partial melting, Phlogopite, Upper mantle, Water",
author = "I. Kov{\'a}cs and Green, {David H.} and Anja Rosenthal and J{\"o}rg Hermann and O'neill, {Hugh St C} and Hibberson, {William O.} and Beatrix Udvardi",
year = "2012",
month = "10",
doi = "10.1093/petrology/egs044",
language = "English",
volume = "53",
pages = "2067--2093",
journal = "Journal of Petrology",
issn = "0022-3530",
publisher = "Oxford University Press",
number = "10",

}

TY - JOUR

T1 - An experimental study of water in nominally anhydrous minerals in the upper mantle near the water-saturated solidus

AU - Kovács, I.

AU - Green, David H.

AU - Rosenthal, Anja

AU - Hermann, Jörg

AU - O'neill, Hugh St C

AU - Hibberson, William O.

AU - Udvardi, Beatrix

PY - 2012/10

Y1 - 2012/10

N2 - The incorporation of water in olivine and pyroxenes interlayered within fertile lherzolite compositions was explored experimentally near the wet solidus of lherzolite at 2·5 and 4 GPa. The concentrations and activities of water were varied to establish the partitioning of water between nominally anhydrous minerals (NAMs) and the hydrous minerals pargasite and phlogopite. The water content in NAMs was determined by Fourier-transform infrared (FTIR) spectroscopy. The main absorption bands in NAMs from these experiments are very similar to those generally found in natural upper mantle peridotites. Olivine, orthopyroxene and clinopyroxene contain 32-190, 290-320 and 910-980 ppm of water under the studied conditions. The partition coefficients between coexisting clinopyroxene and orthopyroxene (D cpx/opx) are 2·7 ± 1·1 and 3·5 ± 1·5 at 2·5 and 4 GPa respectively, whereas values for coexisting orthopyroxene and olivine (D opx/ol) are 6·7 ± 2 and 4·7 ± 1·1, at 2·5 and 4 GPa respectively. The storage capacity in NAMs in a model mantle composition close to the vapour-saturated solidus (water-rich vapour) is ∼190 ppm at both 2·5 and 4 GPa. Pargasite is the most important phase accommodating significant amounts of water in the uppermost mantle. Its breakdown with increasing pressure at 3 GPa at the vapour-saturated solidus (which is at ∼1025°C at 2·5 GPa) results in a sharp drop in the water storage capacity of peridotite from ∼1000 ppm to ∼190 ppm H 2O. At pressures >3 GPa, melting in fertile lherzolite begins at the vapour-saturated solidus if the bulk H 2O concentration exceeds ∼190 ppm.

AB - The incorporation of water in olivine and pyroxenes interlayered within fertile lherzolite compositions was explored experimentally near the wet solidus of lherzolite at 2·5 and 4 GPa. The concentrations and activities of water were varied to establish the partitioning of water between nominally anhydrous minerals (NAMs) and the hydrous minerals pargasite and phlogopite. The water content in NAMs was determined by Fourier-transform infrared (FTIR) spectroscopy. The main absorption bands in NAMs from these experiments are very similar to those generally found in natural upper mantle peridotites. Olivine, orthopyroxene and clinopyroxene contain 32-190, 290-320 and 910-980 ppm of water under the studied conditions. The partition coefficients between coexisting clinopyroxene and orthopyroxene (D cpx/opx) are 2·7 ± 1·1 and 3·5 ± 1·5 at 2·5 and 4 GPa respectively, whereas values for coexisting orthopyroxene and olivine (D opx/ol) are 6·7 ± 2 and 4·7 ± 1·1, at 2·5 and 4 GPa respectively. The storage capacity in NAMs in a model mantle composition close to the vapour-saturated solidus (water-rich vapour) is ∼190 ppm at both 2·5 and 4 GPa. Pargasite is the most important phase accommodating significant amounts of water in the uppermost mantle. Its breakdown with increasing pressure at 3 GPa at the vapour-saturated solidus (which is at ∼1025°C at 2·5 GPa) results in a sharp drop in the water storage capacity of peridotite from ∼1000 ppm to ∼190 ppm H 2O. At pressures >3 GPa, melting in fertile lherzolite begins at the vapour-saturated solidus if the bulk H 2O concentration exceeds ∼190 ppm.

KW - Infrared spectroscopy

KW - Nominally anhydrous minerals

KW - Pargasite

KW - Partial melting

KW - Phlogopite

KW - Upper mantle

KW - Water

UR - http://www.scopus.com/inward/record.url?scp=84866760344&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84866760344&partnerID=8YFLogxK

U2 - 10.1093/petrology/egs044

DO - 10.1093/petrology/egs044

M3 - Article

AN - SCOPUS:84866760344

VL - 53

SP - 2067

EP - 2093

JO - Journal of Petrology

JF - Journal of Petrology

SN - 0022-3530

IS - 10

M1 - egs044

ER -