The Lukinda dunite–troctolite–gabbro massif in the Selenga–Stanovoy superterrane on the southeastern framing of the Siberian Platform was earlier considered Precambrian. The performed 40Ar/39Ar dating of the massif plagioclase yielded an Early Permian age (285 ± 7.5 Ma). The main specific petrochemical features of the intrusion rocks during their crystallization differentiation are an increase in SiO2 and CaO contents and a decrease in FeOtot content, with TiO2 content remaining low and showing minor variations. A specific geochemical feature of the Lukinda massif ultrabasite–basites is a slight domination of LREE over HREE, with (La/Yb)N = 1.0–8.2. The depletion of the massif rocks in LILE (except for Sr and Ba), REE, and HFSE suggests that the massif formed on an active continental margin.