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Shock melting and vaporization of lunar rocks and minerals.The entropy associated with the thermodynamic states produced by hypervelocity meteoroid impacts at various velocities are calculated for a series of lunar rocks and minerals and compared with the entropy values required for melting and vaporization. Taking into account shock-induced phase changes in the silicates, we calculate that iron meteorites impacting at speeds varying from 4 to 6 km/sec will produce shock melting in quartz, plagioclase, olivine, and pyroxene. Although calculated with less certainty, impact speeds required for incipient vaporization vary from 7 to 11 km/sec for the range of minerals going from quartz to periclase for aluminum (silicate-like) projectiles. The impact velocities, which are required to induce melting in a soil, are calculated to be in the range of 3 to 4 km/sec, provided thermal equilibrium is achieved in the shock state.
Document ID
19720046854
Document Type
Reprint (Version printed in journal)
Authors
Ahrens, T. J. (California Institute of Technology Pasadena, Calif., United States)
O'Keefe, J. D. (California, University Los Angeles, Calif., United States)
Date Acquired
August 6, 2013
Publication Date
April 1, 1972
Subject Category
SPACE SCIENCES
Funding Number(s)
CONTRACT_GRANT: NGL-05-007-002
CONTRACT_GRANT: NGL-05-005-105
Distribution Limits
Public
Copyright
Other