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Newest bulk-rock analyses of 18 representative rocks of the Maksyutov complex reflect the presence of MORB, OIB, and IAT basaltic and andesitic series + their metasomatized equivalents. Computed isochemical phase equilibria diagrams in the system Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2 provide minimum P-T conditions of 650-675°C and 2.4-2.6 GPa, whereas Fe-Mg exchange thermometry yield temperatures up to 800-900°C at P=2.5-3.0 GPa. These data indicate the thermal maximum attained by the studied eclogites at their initial stage of decompression ascent, determining the gradient of the metamorphic field. At the same time, previously studied relicts coesite and microdiamond aggregates indicate the maximum pressure that determines the earlier period (in the subduction zone) geothermal gradient: at ~ 600°C, >2.8 GPa for coesite and >3.0 GPa for diamond. In any case, the Maksyutov eclogite complex probably reflects underflow of the Paleo-Asiatic oceanic crust under the continent, and not the subduction of the continental margin.