January 19
Novosibirsk geologists have identified two stages of formation of the Siberian platform crust
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.
Scientists have conducted studies of the content of hafnium isotopes and uranium-lead dating of zircons from crustal xenoliths from the «Udachnaya» kimberlite pipe, located in the central part of the Siberian craton. The studied samples of crustal xenoliths are carried out by kimberlite melt from depths of 10-50 km. The obtained results showed that most of the rocks of the lower layers of the crust of the Siberian craton were formed about 1.8 billion years ago (in Proterozoic), and the upper layers of the earth's crust - 2.7 billion years ago (in Archea).
The work of geologists from the NSU, IGM SB RAS, the universities of Lyon, Clermont and Montpellier (France), devoted to the history of the formation of the continental crust of the Siberian craton, was published in the January issue of the journal Earth and Planetary Science Letters.