The research is aimed at proving the age, nature of parental magma sources, and geodynamic conditions, under which alkaline intrusives of the Tuva Mongolian terrain were introduced. That is relevant when reconstructing development of the Paleoasian Ocean and Paleozoic magmatism in folded frames of the Siberian Craton. The studied Dakhunur intrusion of ultrabasic foidolites and foyaites in the Sangilen Upland is an Early Carboniferous derivative of a Paleozoic alkaline magmatism of the South-Eastern Tuva. According to the precision isotopic Ar-Ar data obtained for the first time, its formation took place ~ 328 Ma. Geochemical features of alkaline rocks of pluton revealed by ICP-MS method indicate the intrusion occurred in a difficult geodynamic environment, where mantle plume interacted with accretionary complexes of active continental margin. Based on this fact, the duration and conditions of a tectonic regime of formation of one of the largest igneous provinces in the Central Asian folded belt are estimated.