Experimental effects of high shock pressure on materials of geological and geophysical interest

[摘要] Shock recovery studies have been performed on a number of materials of geological and geophysical significance using a shock-loading propellant gun. These materials, including silicate glasses, feldspar, orthopyroxene, and pyroxenoid, have been shock-loaded to pressures up to approximately 550 kilobars. Optical and electron microscopic, optical spectral, and x-ray diffraction studies have been carried out on the recovered samples to determine the permanent effects of the shock-loading and the applicability of such information to research on naturally shocked lunar and terrestrial rocks and meteorites. The data on the pyroxene and feldspar are discussed in terms of their usefulness in interpreting, understanding, and calibrating the pressure and temperature conditions of shock metamorphism. The most significant observations include (1) the behavior of the silicate glasses, especially the occurrence of permanent densification until high postshock temperatures cause reversion to low density glass, (2) the permanent reduction of Mn(III) to Mn(II) by shock-loading to 496 kilobars, (3) the shock vitrification of calcic plagioclase to diaplectic and shock-fused glasses at pressures above 300 kilobars, (4) the shockproduction of deformation lamellae in bronzite, and (5) the formation of shock glass in bronzite at 226 kilobars.

[发布机构] University:California Institute of Technology;Department:Geological and Planetary Sciences

[关键词] Geology