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Shock temperatures in calcite (CaCO3): Implication for shock induced decomposition

Gupta, Satish C. and Love, Stanley G. and Ahrens, Thomas J. (2000) Shock temperatures in calcite (CaCO3): Implication for shock induced decomposition. In: Shock compression of condensed matter--1999 : proceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter held at Snowbird, Utah, June 27-July 2, 1999. American Institute of Physics Conference Proceedings. Vol.2. No.505. American Institute of Physics , Melville, NY, pp. 1263-1266. ISBN 1-56396-923-8. https://resolver.caltech.edu/CaltechAUTHORS:GUPaipcp00a

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Abstract

The temperatures induced in crystalline calcite upon planar shock compression (95–160 GPa) are reported from two-stage light gas-gun experiments. The temperatures are obtained fitting 6-channel optical pyrometer radiances in the 450 to 900 nm range, to a Planck radiation law temperature varied from 3300 to 5400 K. Calculations demonstrate that the temperatures are some 400 to 1350 K lower than if either shock-induced melting and/or disproportionation of calcite behind the shock front was not occurring. Here calcite is modeled as disproportionating into a molecular liquid, or a solid CaO plus CO2 gas. For temperature calculations, specific heat at constant volume for one mole of CO2 is taken to be 6.7R as compared to 9R in the solid state; whereas calcite and CaO have their solid state values (15R and 6R). Calculations also suggest that the onset of decomposition in calcite to CaO and CO2 during loading occurs at ~75±10 GPa, along the Hugoniot whereas decomposition begins upon unloading from 18 GPa. The 18 GPa value is based on comparison of VISAR measurements of particle velocity profiles induced upon isentropic expansion with one-dimensional numerical simulation.


Item Type:Book Section
Related URLs:
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https://doi.org/10.1063/1.1303691DOIUNSPECIFIED
Additional Information:©2000 American Institute of Physics. Research supported by NASA. We thank K.G. Holland for helpful comments and M.D. Furnish for useful suggestions. Contribution # 8670 of Division of Geological and Planetary Sciences, (Caltech).
Subject Keywords:minerals; shock wave effects; high-pressure effects; entropy; temperature; dissociation
Series Name:American Institute of Physics Conference Proceedings
Issue or Number:505
Record Number:CaltechAUTHORS:GUPaipcp00a
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:GUPaipcp00a
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3250
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:24 May 2006
Last Modified:02 Oct 2019 23:01

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