Publication Date:
2015-07-03
Description:
In this work a single crystal of synthetic hercynite, FeAl 2 O 4 , was investigated by X-ray diffraction up to 7.5 GPa and at room temperature, in order to determine its pressure–volume equation of state. The unit-cell volume decreases non-linearly with a reduction of 3.4% (i.e. 18.43 Å 3 ). The pressure–volume data were fitted to a third-order Birch-Murnaghan equation of state providing the following coefficients: V 0 = 542.58(3) Å 3 , K T0 = 193.9(1.7) GPa, K ' = 6.0(5). These results are consistent with previous investigations of Cr and Al spinels measured with the same experimental approach but the K T0 differs significantly from the experimental determination carried out more than 40 years ago by Wang and Simmons ( 1972 ) by the pulse echo overlap method. Our new results were used to redetermine the FeAl 2 O 4(hercynite) = FeO (wüstite) + Al 2 O 3(corundum) equilibrium in P–T space and obtain geobarometric information for Cr-Al spinels found as inclusions in diamond.
Print ISSN:
0026-461X
Electronic ISSN:
1471-8022
Topics:
Geosciences
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