Petrology of gabbro-dolerites swarms in the Sharyzhalgai block from neoproterozoic dike with reference to the problem of breakup of the Rodinia supercontinent

Results of the detailed petrological study (including mineralogical, petrol ogical, and geochemical characterization and isotopic dating) of Neoprotero zoic dike swarms in the southern flank of the Siberian craton are employed in discussing the petrogenesis of the dike series and the environments of t heir origin. Variations in the composition of the gabbro-dolerites are dete rmined to have been caused by a combination of partial melting of the magma source and the further fractional crystallization of the melts. The parent al melts of the gabbro dolerites are demonstrated to have been derived with in a lithospheric magmatic chamber early during the extensional stage in th e inner parts of the Rodinia supercontinent.