EXPERIMENTAL-STUDY OF SHOCK AND PULS EVAP ORATION OF ULTRABASITE

Change of ultrabasic rock and their minerals' composition due to shock evaporation has been investigated. This study plays an important role in the interpretation of the geochemical processes taking place durin g accretion stage of the Earth's group planets. Shock and pulse (laser ) evaporation experiments showed preferential evaporation of silica. C omposition of evaporation products shifts to the basic and middle on t he acidity scale. Sharp increase of Si/Mg ratio in the vapor does not depend on water content in the target. Evidences have been obtained th at thermal reduction processes in vapor decrease if water-bearing rock s or minerals was evaporated. The data obtained support the hypothesis of shock evolution of primary ultrabasic matter to the more acid comp osition during vapor condensation on the surface of the growing planet .