Authors: Astrid Schneidewind, Arno Hiess, Hans Boysen

Abstract
Enstatite (MG,Fe)SiO3 with weak amounts of Fe belongs to the pyroxene group of minerals and is an abundant rock forming mineral of the earth's crust an upper mantle. Studying elastic properties of the crystals could be expected to shed light on how far the phase transitions are triggered by preformed stacking faults. Therefore we have investigated the temperature dependence of the dispersion curves of both longitudinal and transverse low energy acoustic phonon branches below and during the phase transition Ortho- to Protoenstatite in the temperature range from room temperature to 1420 °C.