The behaviours of Mg and Ca in some types of ultramaphic alkaline melts in the presence of H 2 O at high temperature and pressure (the experimental data)

The sample has been investigated, which was composed of olivine-melilite rock from the south-western part of the Kugda intrusion, situated in the eastern margin of the Maimecha-Kotuiskay alkaline- ultramaphic province (northern part of Siberia platform). The experiments were carried out using a high-pressure apparatus of the "piston-cylinder" type. The pressure was 5-15 kb and the temperature -800-1250 0 C. The water content in the system was 3 and 9 wt. All experiments were carried out in hermetically sealed Pt or Au ampoules. The samples were chemically analyzed using a scanning electron microscope (SEM). Besides, the chemical composition of the experimental phases was determined by means of more than 40 electron microprobe in 20 experimental samples. For phase identification the X-ray method was used too. The structural peculiarities of rocks and mineral compositions were studied by optical methods in polished and thin sections prior and after the experiment. It was shown that at pressures above 7.5-8 kb the olivine-melilite melt is separated into two melts: pyroxenite and melilite. Most part of Mg in this system was concentrated in a high temperature phase of diopside type. The remaining melt was depleted of Mg and enriched by Ca. The mineralization vapour practically did not contain Mg. The main components of the mineralization vapour were Ca, Na, Si and Fe

The banding in serpentinites and its influence on character of talc-magnesite and magnesite mineralization (natural and experimental data)

The geological setting of some banded talc-magnesite ores and magnesites was studied in the field (Urals, Russia; Finland, East Iran). Talc-magnesite and magnesite ores occur in ultramafic rocks. Experimental methods were used in order to determine the influence of physico-mechanical parameters on the formation of banded structures in talc-magnesite rocks and magnesites. Experiments were carried out with axial compression up to 10 kbar and confining pressure 2, 4, 6 and 8 kbars at room temperature. The samples were chemically analyzed using a Philips Analytical PW 2400 authomatic XRF Spectrometer and a scanning electron microscope (SEM). Some analyses were made with a "Camebax SX-50" electron microprobe, using an accelerating voltage of 20 kilovolts for all elements with a sample current of 20 nanoamps. X-ray method for phase identification was used. Structure peculiarities of rocks prior to the experiment and after were studied by optical methods in polished sections and thin sections. It was shown, that banding in talc-magnesite stone and magnesites are inherited from banded serpentinites and can affect on distribution and composition rock-forming minerals

Academical stress for the first and second year medical students and possible risks to mental health

Medical student’s activity is one of the strained types of labor in emotional aspects. This affects the level of their mental and physical health. In this study, we conducted a comparative analysis of the educational stress of first and second year medical students. The sample included all russian-speaking students. The academic stress, stressresistance, level of anxiety and depression were studie