ИСТИНА

To clarify the nature of the petrogenetic processes that included in the formation of the Yoko-Dovyrensky layered intrusion, its rock, perhaps for the first time, were examined by structural petrology methods. Samples of dunite, wehrlite and troctolite were studied: the crystal size distribution of olivine, as well as the misorientation of its contact grains, were analyzed. By the analysis of the data maked a hypothesis about the complementarity of anortosites and wehrlites of Yoko-Dovyren and their formation by layering of primary troctolite cumulus mush. The dunites of the massif represent the earliest cumulates, the formation regime of which was different from that for wehrlites, although in the latter only olivine acts as the only cumulus phase.