A Caltech Library Service

Shock compression of a recrystallized anorthositic rock from Apollo 15

Ahrens, Thomas J. and O'Keefe, John D. and Gibbons, Rex V. (1973) Shock compression of a recrystallized anorthositic rock from Apollo 15. In: Proceedings of the Fourth Lunar Science Conference. Geochimica et cosmochimica acta. Supplement; 4. No.3. Pergamon Press , New York, NY, pp. 2575-2590.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


Hugoniot measurements on 15,418, a recrystallized and brecciated gabbroic anorthosite, yield a value of the Hugoniot elastic limit (HEL) varying from - 45 to 70 kbar as the final shock pressure is varied from 70 to 280 kbar. Above the HEL and to 150 kbar the pressure-density Hugoniot is closely described by a hydrostatic equation of state constructed from ultrasonic data for single-crystal plagioclase and pyroxene. Above - 150 kbar, the Hugoniot states indicate that a series of one or more shock-induced phase changes are occurring in the plagioclase and pyroxene. From Hugoniot data for both the single-crystal minerals and the Frederick diabase, we infer that the shock-induced high-pressure phases in 15,418 probably consist of a 3.71 g/cm^3 density, high-pressure structure for plagioclase (An_(93)) and a 4.70 g/cm^3 perovskite-type structure (En_(64)) for pyroxene. Using the Kelly Truesdell mixture theory we separately calculated the entropy production in each phase, and predict incipient and complete melting in the plagioclase occurs upon release from ~ 500 and ~ 600 kbar. For the pyroxene component, incipient and complete melting occurs upon release from 700 and 850 kbar. The onset of shock-induced vaporization will occur upon release from ~ 1300 kbar and would require the impact of an iron meteoroid traveling at a velocity of ~8 km/sec.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Additional Information:© 1973 Lunar and Planetary Institute. Provided by the NASA Astrophysics Data System. Contribution No. 2142, Division of Geological and Planetary Sciences, California Institute of Technology. We appreciate the help of A. Chodos in characterizing our sample and the excellent experimental assistance of H. Richeson and D. Johnson. Supported under NGL-05-005-105 and NGL-05-007-002 at the California Institute of Technology and the University of California, respectively.
Funding AgencyGrant Number
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences2142
Series Name:Geochimica et cosmochimica acta. Supplement; 4
Issue or Number:3
Record Number:CaltechAUTHORS:20150709-112806665
Persistent URL:
Official Citation:Shock compression of a recrystallized anorthositic rock from Apollo 15 Ahrens, T. J., O'Keefe, J. D., & Gibbons, R. V. Proceedings of the Lunar Science Conference, vol. 4, p.2575
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:58826
Deposited By: Ruth Sustaita
Deposited On:22 Jul 2015 18:56
Last Modified:03 Oct 2019 08:40

Repository Staff Only: item control page