The results of 190Pt–4He dating of placer-forming minerals of native platinum (PPM) from the cascade of platinum metal placer deposits of br. Mokhovaya, its tributaries and eluvium and proluvium of the peneplain surface developed on the dunites of the alkaline-ultramafic massif Chad (Aldan shield, Ayano-Maisky district of the Khabarovsk Territory) are presented. 190Pt and 4He were analyzed in 27 samples. Statistical processing of mineralogical and geochemical data allows to separate three isochrones with 190Pt–4He ages: 123 ± 6 Ma; 113 ± 6 Ma; 107 ± 6 Ma, which is in good agreement with the geological observations, and most importantly with the mineralogy of the platinum group elements (PGE) of the Chad massif. The range of 190Pt–4He age isochrones indicates the formation of platinum-metal ore formation was during 16 Myr. The geological and mineralogical data and the presence of 190Pt–4He isochrones of different ages allow us to conclude that the platinum-metal ore formation of the Chad massif was polycyclic during the Early Cretaceous. Comparison of the 190Pt–4He ages of the PPM of the alkaline-ultramafic massifs Chad and Kondyor testifies to the temporal nuances of platinum-metal mineral formation and the formation of the plutons themselves in the development of the Mesozoic tectonic-magmatic activation of the Aldan Shield.