The original cause of the Late Mesozoic tectonic-magmatic and mineragenic activation at the Pre-Cambrian Aldan Shield was the existence of the stagnated oceanic slab in the mantle transitional zone. Dehydration of the slab rocks (especially those on its boundaries) and accompanying events promoted the lower mantle derivatives to be involved into the ascending upper mantle flows (plumes) and favored the formation of the productive ore-magmatic systems.
