Shock Wave Equations of State of Chondritic Meteorites

We have obtained shock compression data for Murchison and Bruderheim chondritic meteorites. Data for Murchison suggest that the Hugoniot states are described by a smooth curve to >_90 GPa. having po = 2.656 Mg/m 3 . Kso = 24.2±.7 GPa, K'= 4.17±. 10, and constant y = 1.0. The data for Bruderheim suggest more complicated behavior. A mineral mixture model consistent with the Bruderheim data suggests that the Hugoniot state is a low pressure phase below 25 GPa, with po = 3.555 Mg/m . Ks, = 146 GPa. K'= 2.53. and constant py = 7.11 Mg/m 3 , and a high pressure phase above 65 GPa. with po = 4.40 Mg/m . Kso = 225 GPa. K'= 3.25, and constant py = 7.485 Mg/m 3 .