Scientists from the Laboratory of Experimental Geochemistry and Petrology of the Earth's Mantle of the Novosibirsk State University and the Institute of Geology and Mineralogy named after. VS Sobolev (IGM) of the SB RAS, together with colleagues from the universities of Lyon, Clermont and Montpellier (France), investigated samples from the «Udachnaya» kimberlite pipe and found that the continental crust of the Siberian craton has been forming in two stages: The upper layer - 2.7 billion years ago, the lower layer - 1.8 billion years. Before that, it was thought that cratons were formed 2.5 billion years ago.