Variation in the Elastic Constants of Calcite with Temperature

Abstract

The temperature dependence of the elastic constants of calcite have been investigated by the ultrasonic phase‐comparison method from 25° to 375°C. The variation in the elastic constants and the elastic moduli of calcite is smooth and linear over the temperature range, and does not show the break in the variation of the elastic moduli with temperature reported by Reddy and Subrahmanyam at 200°C. The results of the present investigation are in agreement with the other related high‐temperature studies of calcite. The reported discontinuity in the variation of elastic moduli with temperature thus seems to be inconsistent with the high‐temperature behavior of calcite. This conviction is strengthened by the impossible behavior of compressibility of calcite with temperature as obtained from the calcite data of Reddy and Subrahmanyam. The elastic constants of calcite at T°C within the temperature range of the present work are adequately represented by the following equations: $$\begin{array}{c}{\mathrm{\hspace{0.17em}C}}_{11}{\text{=14.7994−57.82×10}}^{\text{−4}}\text{×(T−25)}\\ C_{33}{\text{=8.5694−14.06×10}}^{\text{−4}}\text{×(T−25)}\\ C_{44}{\text{=3.2790−14.36×10}}^{\text{−4}}\text{×(T−25)}\\ C_{66}{\text{=4.6316−14.03×10}}^{\text{−4}}\text{×(T−25)}\\ C_{13}{\text{=5.4540−25.76×10}}^{\text{−4}}\text{×(T−25)}\\ {\mathrm{\hspace{0.17em}C}}_{14}{\text{=−2.0966+8.32×10}}^{\text{−4}}\text{×(T−25)}\end{array}$$ .