Premelting effects in minerals: an experimental study

摘要: High-temperature calorimetry experiments show that the isobaric heat capacity (C(p)) of minerals increases in an anomalously rapid way when melting point is approached. These premelting effects can begin a few hundred degrees below point, and they should also be observed for other physical properties such as thermal expansion, compressibility sound velocities. Premelting could thus affect partially molten rocks. In this study, new evidence diopside (CaMgSi2O6), pseudowollastonite (CaSiO3), anorthite (CaAl2Si2O8), akermanite (Ca2MgSi2O7), Na2SiO3, L2SiO3 CaMgGeO4 olivine obtained by means calorimetry, electron microscopy vibrational spectroscopy, demonstrates represents unquenchable configurational changes within phases remaining crystalline up to reported points. The enthalpy entropy are consistent with cation disordering over various crystallographic sites structures. More generally, temperature-induced at roots intrinsic anharmonicity oxide silicate compounds.