Equation of state for natural almandine, spessartine, pyrope garnet: Implications for Quartz-in-Garnet elastic geobarometry

TY - JOUR

T1 - Equation of state for natural almandine, spessartine, pyrope garnet

T2 - Implications for Quartz-in-Garnet elastic geobarometry

AU - Mulligan, Suzanne R.

AU - Stavrou, Elissaios

AU - Chariton, Stella

AU - Tschauner, Oliver

AU - Salamat, Ashkan

AU - Wells, Michael L.

AU - Smith, Alexander G.

AU - Hoisch, Thomas D.

AU - Prakapenka, Vitali

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/5

Y1 - 2021/5

N2 - The equation of state (EoS) of a natural almandine74spessartine13pyrope10grossular3 garnet of a typical composition found in metamorphic rocks in Earth’s crust was obtained using single crystal synchrotron X-ray diffraction under isothermal room temperature compression. A third-order Birch-Murnaghan EoS was fitted to P-V data and the results are compared with published EoS for iron, manganese, magnesium, and calcium garnet compositional end-members. This comparison reveals that ideal solid solution mixing can reproduce the EoS for this intermediate composition of garnet. Additionally, this new EoS was used to calculate geobarometry on a garnet sample from the same rock, which was collected from the Albion Mountains of southern Idaho. Quartz-in-garnet elastic geobarometry was used to calculate pressures of quartz inclusion entrapment using alternative methods of garnet mixing and both the hydrostatic and Grunëisen tensor approaches. QuiG barometry pressures overlap within uncertainty when calculated using EoS for pure end-member almandine, the weighted averages of end-member EoS, and the EoS presented in this study. Grunëisen tensors produce apparent higher pressures relative to the hydrostatic method, but with large uncertainties.

AB - The equation of state (EoS) of a natural almandine74spessartine13pyrope10grossular3 garnet of a typical composition found in metamorphic rocks in Earth’s crust was obtained using single crystal synchrotron X-ray diffraction under isothermal room temperature compression. A third-order Birch-Murnaghan EoS was fitted to P-V data and the results are compared with published EoS for iron, manganese, magnesium, and calcium garnet compositional end-members. This comparison reveals that ideal solid solution mixing can reproduce the EoS for this intermediate composition of garnet. Additionally, this new EoS was used to calculate geobarometry on a garnet sample from the same rock, which was collected from the Albion Mountains of southern Idaho. Quartz-in-garnet elastic geobarometry was used to calculate pressures of quartz inclusion entrapment using alternative methods of garnet mixing and both the hydrostatic and Grunëisen tensor approaches. QuiG barometry pressures overlap within uncertainty when calculated using EoS for pure end-member almandine, the weighted averages of end-member EoS, and the EoS presented in this study. Grunëisen tensors produce apparent higher pressures relative to the hydrostatic method, but with large uncertainties.

KW - Equation of state

KW - Garnet

KW - Host inclusion elastic geobarometry

KW - QuiG

KW - Solid solution

UR - http://www.scopus.com/inward/record.url?scp=85104807424&partnerID=8YFLogxK

U2 - 10.3390/min11050458

DO - 10.3390/min11050458

M3 - 文章

AN - SCOPUS:85104807424

SN - 2075-163X

VL - 11

JO - Minerals

JF - Minerals

IS - 5

M1 - 458

ER -