Defects in Deformed Calcite and Carbonate Rocks

Abstract

Deformation of calcite crystals and rocks was the subject of an intensive investigation between 1950 and 1960. Through U-stage analysis of experimentally deformed material, deformation mechanisms were established and their variations were studied over a wide range of temperatures (for example Turner et al., 1954; Griggs et al., 1960). From this work it was concluded that at low temperatures, deformation occurs largely by twin gliding on $e = \left\{ {01\overline 1 } \right\}^1 with\left\langle {01\overline 1 \overline 1 } \right\rangle$ as glide direction and at higher temperature translation gliding on the unit rhomb$r = \left\{ {10\overline 1 1} \right\}with\left\langle {\overline 1 012} \right\rangle$ as glide direction dominates. Other mechanisms such as translation on the a-prism (Paterson and Turner, 1970) or on $f = \left\{ {02\overline 2 1} \right\}$ (Keith and Gilman, 1960) can also operate but because critical shear stresses are much higher, these systems are more rarely observed. Preferred orientation in deformed aggregates is in agreement with deformation predominantly by r-translation and e-twinning (for example Wenk et al., 1973).