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Information × Registration Number 0209U006110, 0107U007411 , R & D reports Title High degree melting in the early history of the Ukrainian, Canadian and South African pre-cambrian shields; the conditions in which it had occured and its consequenses by geochemical and geoelectrical data. popup.stage_title Head Aryasova Olga Viktorivna, Registration Date 26-01-2009 Organization S.I.Subbotin Institute of geophysics HASU. popup.description2 Results of numerical modeling of rare-earth elements (REE) large-scale fractionation in cratonic mantle are presented, and conditions under which the mantle rocks are in diffusion equilibrium are considered. It is shown that the large-scale fractionating is due to the PT-dependence of diffusion coefficients resulting in a non-equilibrium and depth deреndent REE partition between melt and restite during episodes of depleted peridotite moderately high degree melting. At depths in excess of about 200 km the characteristic REE diffusion time is short, and the REE abundances in mantle minerals are diffusively equilibrated. This can be the basic reason of the similarity of the rare element patterns observed in the world kimberlite provinces. The geoelectrical data for the Western part of Ukrainian Shild are analyzed, and a 3D geoelectrical model of Ukrainian Shield is developed. Product Description popup.authors popup.nrat_date 2020-04-02 Close