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Shock-wave equation of state of rhyolite

Anderson, William W. and Yang, Wenbo and Chen, George and Ahrens, Thomas J. (1998) Shock-wave equation of state of rhyolite. Geophysical Journal International, 132 (1). pp. 1-13. ISSN 0956-540X. http://resolver.caltech.edu/CaltechAUTHORS:20141028-155251695

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Abstract

We have obtained new shock-wave equation of state (EOS) and release adiabat data for rhyolite. These data are combined with those of Swegle (1989, 1990) to give an experimental Hugoniot which is described by U_s = 2.53(±0.08) + 3.393(±0.37)u_p for u_p < 0.48 km s^(−1), U_s = 3.85(±0.05) + 0.65(±0.03)up for 0.48 ≤ u_p < 2.29 km s^(−1), U_s = 1.52(±0.08) + 1.67(±0.02)u_p for 2.29 ≤ u_p < 4.37 km s^(−1), and U_s = 3.40(±034) + 1.24(±0.06)u_p for u_p ≥ 4.37 km s^(−1), with ρ_0 = 2.357 ± 0.052 Mg m^(−3). We suggest that the Hugoniot data give evidence of three distinct phases—both low- and high-pressure solid phases and, possibly, a dense molten phase. EOS parameters for these phases are ρ_0 = 2.494 ± 0.002 Mg m^(−3), K_(S0) = 37 ± 2 GPa, K′ = 6.27 ± 0.25, and γ = 1.0(V/V_0) for the low-pressure solid phase; ρ_0 = 3.834 ± 0.080 Mg m^(−3), K_(S0) = 128 ± 20 GPa, K′ = 3.7 ± 1.4, and γ = 1.5 ± 0.5 for the solid high-pressure phase; and ρ_0 = 3.71 ± 0.10 Mg m^(−3), K_(S0) = 127 ± 25 GPa, K′ = 2.1 ± 1.0, and γ = 1.5 ± 1.0 for the dense liquid. Transition regions of the Hugoniot cover the ranges of 9–34 GPa for the low-pressure—high-pressure solid transition and 90–120 GPa for the high-pressure solid—liquid transition. Release paths from high-pressure states, calculated from the EOS parameters, suggest that the material remains in the high-pressure solid phase upon release. Release paths from both the high-pressure solid and liquid fall above the Hugoniot until the Hugoniot enters the low-pressure—high-pressure mixed phase region, when the release paths then cross the Hugoniot and fall below it, ending at significantly higher zero-pressure densities than that of the low-pressure phase. The low-pressure release paths fall very close to the Hugoniot. Estimates of residual heat deposition, based on shock-release path hysteresis, range from 20 to 60 per cent of the shock Hugoniot energy.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1046/j.1365-246x.1998.00389.xDOIArticle
http://gji.oxfordjournals.org/content/132/1/1.abstractPublisherArticle
Additional Information:© 1998 RAS. Accepted 1997 June 25. Received 1997 June 23; in original form 1997 February 10. We thank E. Gelle and M. Long for assistance in the experiments and R. Blandford, R. Stagat, S. Peyton and K. McLaughlin for helpful technical discussions. This work was supported by NASA Grant NAGW-1941 and by the US Air Force Technical Applications Center under subcontract #SC-0064-90-0002 from Mission Research Corporation. Contribution 5634, Division of Geological and Planetary Sciences.
Funders:
Funding AgencyGrant Number
NASANAGW-1941
Mission Research CorporationSC-0064-90-0002
Subject Keywords:equations of state; rhyolite; shock waves
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Caltech Division of Geological and Planetary Sciences5634
Record Number:CaltechAUTHORS:20141028-155251695
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20141028-155251695
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50963
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:28 Oct 2014 23:47
Last Modified:28 Oct 2014 23:47

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