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Shock compression of single-crystal forsterite

Watt, J. Peter and Ahrens, Thomas J. (1983) Shock compression of single-crystal forsterite. Journal of Geophysical Research B, 88 (B11). pp. 9500-9512. ISSN 0148-0227. https://resolver.caltech.edu/CaltechAUTHORS:20141031-122339769

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Abstract

Dynamic compression results are reported for single-crystal forsterite loaded along the orthorhombic a and c axes to pressures from 130 to 165 GPa. Hugoniot states for the two axes are well described by a single curve offset to densities 0.15–0.20 g/cm^3 lower than earlier data for single-crystal forsterite shocked along the b axis above 100 GPa. Earlier data of Syono et al. [1981a] show marginal support for similar b-axis behavior in the mixed-phase region from 50 to 92 GPa. Thus shocked forsterite is most compressible in the b direction for the mixed-phase and high-pressure regimes (P > 50 GPa). These data represent the highest pressures for which shock properties have been observed to depend on crystal orientation. Theoretical Hugoniots for mixed-oxide and perovskite-structure high-pressure assemblages of forsterite calculated from recent experimental data are virtually identical and agree with the b-axis data. The a- and c-axis data are also consistent with both high-pressure assemblages because uncertainties in equation of state parameters produce a broad range of computed Hugoniots. Our calculated “average” Hugoniot is up to 0.13 g/cm^3 less dense than the preferred theoretical Hugoniots, in agreement with earlier measurements on dense polycrystalline forsterite. Interpolation between the single-crystal forsterite Hugoniots and Hugoniots for fayalite and Fo_(45) gives Fo_(88) Hugoniots bracketing Twin Sisters dunite data not previously well fit by systematics. Release paths are steep for the a and b axes but c-axis release paths are much shallower. Hugoniot elastic limits measured for the a and b axes are in good agreement with previous data of Syono et al.; however, the present data for the a axis reveal a triple wave structure: two deformational shock waves as well as the elastic shock, a feature not previously found. The second shock, with amplitude about 9 GPa and a shock temperature of about 350°K, could perhaps be explained by the forsterite α→β or γ phase transformation.


Item Type:Article
Related URLs:
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http://dx.doi.org/10.1029/JB088iB11p09500DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/JB088iB11p09500/abstractPublisherArticle
Additional Information:Copyright 1983 by the American Geophysical Union. (Received September 23, 1982; revised June 2, 1983; accepted June 16, 1983.) Paper number 3B1078. We appreciate the careful construction and execution of these experiments by E. Gelle and M. Long and acknowledge useful discussions with G. A. Lyzenga andJ. M. Vizgirda. D. L. Anderson offered helpful comments on the manuscript. We are grateful to T.J. Shankland for providing these crystals to us. Computing support was provided by the Office of Computing Services and the Department of Geology, Rensselaer Polytechnic Institute. Supported by NSF grant EAR 80-18819. Contribution 3809, Division of Geological and Planetary Sciences, California Institute of Technology.
Funders:
Funding AgencyGrant Number
NSFEAR 80-18819
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences3809
Issue or Number:B11
Record Number:CaltechAUTHORS:20141031-122339769
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141031-122339769
Official Citation:Wett, J. P., and T. J. Ahrens (1983), Shock compression of single-crystal forsterite, J. Geophys. Res., 88(B11), 9500–9512, doi:10.1029/JB088iB11p09500.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51124
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:31 Oct 2014 20:10
Last Modified:03 Oct 2019 07:30

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