Pressure Dependence of the Elastic Constants of Calcite

Abstract

The values of the six elastic constants of single-crystal calcite are determined to 6 kbar at 25\ifmmode^\circ\else\textdegree\fi{}C by the pulse-echo method. The values of these constants at 1 atm and 25\ifmmode^\circ\else\textdegree\fi{}C agree fairly well with those obtained by Peselnick and Robie. The value of ${C}_{11}$ increases from 14.63\ifmmode\times\else\texttimes\fi{}${10}^{11}$ dyn/${\mathrm{cm}}^{2}$ to 14.70\ifmmode\times\else\texttimes\fi{}${10}^{11}$ dyn/${\mathrm{cm}}^{2}$ at 6 kbar. The values of ${C}_{33}$ and ${C}_{66}$ do not change with pressure to 6 kbar. These values are, respectively, 8.53\ifmmode\pm\else\textpm\fi{}0.05 and 4.33\ifmmode\pm\else\textpm\fi{}0.07\ifmmode\times\else\texttimes\fi{}${10}^{11}$ dyn/${\mathrm{cm}}^{2}$. The increases in the magnitude of ${C}_{13}$ and ${C}_{14}$ are nonlinear. The variation of ${C}_{44}$ shows a maximum between 3 and 4 kbar. The possible reasons for such a maximum are qualitatively discussed.