Samborskaya I. Geochemistry of layered magmatic rocks of Alexandrovskaya intrusion (Middle-Dnieper megablock of Ukrainian Shield)

Characteristics of chemical composition of main types of rocks and minerals of Alexandrovskaya intrusion are analyzed. Geochemical and petrochemical characteristics of rocks are considered. Petrogenetical model of formation is represented, ore specialisation of rocks of this intrusion is determined. According mineralogical composition, texture-structural characteristics and chemical composition dunites, lherzolites, websterites, norites, gabbronorites, gabbro, andesine anorthosites, diorites, granodiorites and plagiogranites are distinguished among intrusion rocks. Due to geochemical researches Alexandrovskaya intrusion was established as layered intrusion with clear differentiation of rocks. Concealed stratification of ultramafites and mafites rocks are established. Ultramafic rocks (dunites, lherzolites, websterites) are proved to be a cumulative rocks. Andesine anorthosites are pick out for the first, their belonging is established together with diorites, granodiorites and plagiogranites to single series of magmatic rocks. Plagiogranites of Alexandrovskaya іntrusion are established to have considerable geochemical differences from plagiogranites of Sursky complex of Middle-Dnieper megablock, this indicated on it's different magmatic sources and conditions of formation. Distribution of ore elements in rocks and minerals was studied, it was concluded that Alexandrovskaya intrusion is potentially nickel-carrying.