Document Type

Article

Publication Date

4-27-2021

Publication Title

Minerals

Publisher

MDPI

Volume

11

Issue

5

First page number:

1

Last page number:

12

Abstract

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-ingarnet 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 endmember 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.

Keywords

Garnet; Equation of state; Solid solution; Host inclusion elastic geobarometry; QuiG

Disciplines

Earth Sciences | Geology | Mineral Physics

File Format

pdf

File Size

869 KB

Language

English

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Download


Share

COinS