ИСТИНА

Experimental study of interaction in the GLOSS-peridotite system in a wide P-T range allowed us to investigate phase relations, interphase element partitioning, and patterns of isomorphism in high-pressure minerals including hydrous phases. Most of the samples contain the intermediate (reaction) zones between the zones of GLOSS and peridotite modeling the crust-mantle interaction at different pressures corresponding to the upper mantle (7 GPa), transition zone (18 GPa) and uppermost lower mantle (24 GPa). We simulated the reactions between peridotite and GLOSS resulting in the formation of high-Al phases in the transition zone and lower mantle, mostly within the MgSiO3-Al2O3 series. The phase associations obtained in our runs show probability of the formation of hydrous Al-rich phases (up to 8 wt % H2O) upon crust-mantle interaction; some of this phases may supply water to the Earth's transition zone and lower mantle.