Accession Number : ADA296929

Title :   Shock Propagation in Crustal Rocks: Sandstone, Limestone and Shale.

Descriptive Note : Final rept.,

Corporate Author : CALIFORNIA INST OF TECH PASADENA SEISMOLOGICAL LAB

Personal Author(s) : Ahrens, Thomas J. ; Anderson, William W. ; Zhao, Yusheng

PDF Url : ADA296929

Report Date : APR 1995

Pagination or Media Count : 56

Abstract : We present shock compression and release data for Coconino Sandstone, Solenhofen and Bedford limestones, and Chambless shale. Urnestone, sandstones, and shale display three separate phases on the Hugoniot curve. For sandstone these are quartz, stishovite, and a dense liquid. The limestone Hugoniot phases are calcite 1 and a dense liquid, with an intervening phase of either calcite 3 or aragonite. For dense liquid SiO2, Po=4.150 Mg/m3 and Kso=313.5 GPa. For dense liquid CaCO3, Po=3.377 Mg/m3 and Kso=139 GPa. Shock-induced phase transitions in both rocks are kinetically inhibited. Formulation of pressure phase can be modeled by f = Ae(-Ea/RT). For stishovite from quartz, A = 7.286 and Ea (kJ/mol) = 89.36-71.97 (Po/Poo), where Po and Poo are the non-porous and actual initial densities of the rock. A = 6.245 x 1O to the 9th power and Ea = 404+0.312 Poo for formation of SiO2 liquid from stishovite. Carbonate-rich (approx. 33% CaCO3 by weight) shale has a bulk modulus of Kso = 30.9 GPa. This appears to be the result of the clay/mica ratio and the presence of zeolitic water in the carbonate-rich shale rather than carbonate content Carbonate-rich shale transforms to high-pressure phase assemblages, with marked increases in density (p =3.6559,3.740 Mg/m3 for kaolinite, carbonate-rich and carbonate-poor shales, and slate, respectively, at P = 0), on shock compression. The behavior of this high pressure phase material is strongly influenced by the abundance of H2O in the rock. Release adiabat data show conversion of high to low<density material for shale upon release. Sandstone retains a factor of-2 more shock energy than limestone, so decoupling of explosions from seismic waves will be more efficient in sandstones. (AN)

Descriptors :   *SHOCK WAVES, *LIMESTONE, *SANDSTONE, *SEISMIC WAVES, *SHALE, COMPRESSION, PRESSURE GRADIENTS, MATHEMATICAL MODELS, DENSITY, PHASE TRANSFORMATIONS, ENERGY, EXPLOSIONS, GROUND SHOCK, HIGH PRESSURE, DISPLAY SYSTEMS, SEISMIC DATA, QUARTZ, WAVE PROPAGATION, LIQUID PHASES, HIGH DENSITY, CLAY, ARAGONITE, CALCITE, DECOUPLING, EARTH CRUST, COMPOSITION(PROPERTY), ADIABATIC CONDITIONS, EQUATIONS OF STATE, SEDIMENTARY ROCK, KAOLINITE, MICA, BULK MODULUS.

Subject Categories : Geology, Geochemistry and Mineralogy
      Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE