Accession Number : ADA301302

Title :   Equation of State of Clay, Shale and Slate.

Descriptive Note : Technical rept. 30 Sep 92-30 Apr 95,

Corporate Author : CALIFORNIA INST OF TECH PASADENA SEISMOLOGICAL LAB

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

PDF Url : ADA301302

Report Date : 01 NOV 1995

Pagination or Media Count : 60

Abstract : New shock compression and release adiabat data to approx. 150 GPa are reported for kaolinite clay and rocks derived from clay- and mica-rich materials. The kaolinite data yield an STP isentropic bulk modulus (Kso) of 49.4 GPa. This is very similar to K% for muscovite mica (52 GPa), although the density is lower (2.594 Mg/rn3 vs. 2.835 Mg/rn3 for muscovite). Unlike muscovite, kaolinite apparently transforms to a new (unidentified) phase under shock compression. Carbonate-poor shale (approx. 8% CaCO3 by weight) is less compressible (Ks0 = 61.1 GPa) than a carbonate-rich (-33% CaCO3 by weight) shale (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. The compressibility of slate (Kso = 50.5 GPa) is very similar to that of carbonate-poor shale at low pressures. All of these rocks transform to high-pressure phase assemblages, with marked increases in density (r = 3.359, 3.659, 3.740, and 4.110 Mg/rn3 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 in kaolinite and shales upon release, but not in slate. (AN)

Descriptors :   *CLAY, *EQUATIONS OF STATE, *SHALE, MATHEMATICAL MODELS, DENSITY, PHASE TRANSFORMATIONS, WATER, SHOCK WAVES, X RAY DIFFRACTION, HIGH PRESSURE, PHASE STUDIES, ROCK MECHANICS, QUARTZ, COMPRESSIVE STRENGTH, COMPOSITION(PROPERTY), ADIABATIC CONDITIONS, HYSTERESIS, SILICATES, HYDROXIDES, KAOLINITE, MICA, BULK MODULUS, CARBONATE MINERALS, METAMORPHIC ROCK.

Subject Categories : Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE