Experimental and Theoretical Studies of the Viscosity of the Fluid Magmatic Systems in Conjunction with the Structure of Melts at the Thermodynamic Parameters of the Earth’s Crust and Upper Mantle

Paper provides a brief overview of the results of the established general regularities of the concentration, temperature, pressures and phase dependency of viscosity of the fluid-magmatic systems in connection with the anniversary of IEM RAS (50 years have passed since the establishment of this unique Institution). The study of the viscosity of such melts was carried out in the full range of compositions of natural magmas (acid-ultrabasic) in a wide range of fluid compositions (Ar, H2O, H2O + HCl, H2O + NaCl, H2O + HF, CO2, H2O + CO2, H2), and thermodynamic parameters of the earth’s crust and upper mantle (T = 800°–1950 °C, P = 100 MPa–12.0 GPa, Pfl= 10–500 MPa). The study of the viscosity of such melts was carried out in the IEM RAS in conjunction with the study of structural features of melts. The features of the unique equipment and techniques developed in the IEM RAS for such original studies are briefly considered. The possibilities and advantages of the developed structural-chemical model of reliable predictions and calculations of viscosity of fluid-magmatic systems in the full range of magma compositions from acidic to ultramafic at thermodynamic parameters of the earth’s crust and upper mantle are discussed. Some examples of successful application of the obtained experimental and theoretical results to natural processes are briefly considered.