Static and Dynamic Compression of Earth Materials

The triennium, 1967 -1970 , has been a period of marked increase in acquisition of pressure-volume data for minerals, rocks, and compounds of geophysical interest. A wide assortment of data has been obtained by the conventional dilatometric techniques as well as by the more recently developed X-ray diffraction and shock-wave techniques. Highlights of progress during the last 3 years include hydrostatic compression measurements for Apollo 11 lunar samples [Stephens and Lilley, 1970; Schreiher et al., 1970] , static compression measurements of the spinel phase of (Mg,Fe)2SiC>4 solid solutions, which are likely constituents of the transition zone of the earth's mantle [Mao et al., 1969] , and Hugoniot data for high-pressure phases of ferromagnesian silicates, which may represent the constituents of the lower mantle [McQueen et al., 19676].