Experimental measurements of the fugacity of CO2 and graphite/diamond stability from 35 to 77 kbar at 925 to 1650°C

Saved in:
Online Access: Get full text
doi: 10.1016/S0016-7037(97)00035-5
Authors:Frost, Daniel J.; Wood, Bernard J.
Author Affiliations:Primary:
University of Bristol, Department of Geology, Bristol, United Kingdom
Volume Title:Geochimica et Cosmochimica Acta
Source:Geochimica et Cosmochimica Acta, 61(8), p.1565-1574. Publisher: Pergamon, Oxford, International. ISSN: 0016-7037
Publication Date:1997
Note:In English. 59 refs.; illus., incl. 4 tables
Summary:The GCO and DCO oxygen buffer describe the upper fO2 stability of graphite or diamond with respect to a free C-O fluid. Of the available equations of state for CO2, the best agreement is found with that of Saxena & Frei, though this is outside the limits of experimental uncertainty at high P and low T. The results are accordingly parameterized with data from studies at a lower P in terms of a Redlich-Kwong type EOS. The new equation fits the experimental fugacity data within 0.15 log units at high P and agrees with low-P (<<<[dollar]I> 40 kbar) phase equilibrium data and experimental P-V-T measurements. The reactions which determine the speciation of C in the system Mg-Si-C-O are shown and T calculated for a typical mantle adiabat, the fO2 being referenced to the fayalite magnetite quartz buffer. It is unlikely that a C-O fluid could exist at P >><[dollar]I> 40 kbar in a mantle dominated by olivine. [R.K.H.]
Subjects:Applications; Carbon dioxide; Diamond; Equations of state; Experimental studies; Fugacity; Graphite; Mantle; Native elements; P-T conditions; Phase equilibria; Stability; Upper mantle
Abstract Numbers:97M/3816
Record ID:1997042764
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Tags: Add Tag
No Tags, Be the first to tag this record!
Be the first to leave a comment!
You must be logged in first