A.I. LARICHEV, S.V. VIDIK, S.A. SERGEEV, I.V. OSADCHIY (VSEGEI)

Petrographic description and age of Aldan-Anabar block rocks of the Siberian Platform basement according to deep well logs

Results of studying the petrographic and chemical composition and determining the absolute age of basement rocks of the central Siberian Platform are described. Chemically, the analyzed rocks belong to the acid and medium rocks of the normal and moderately alkaline series of the pluton class. The REE distribution spectra, normalized to chondrite, are characterized by the predominance of light elements over heavy ones; at the level of heavy elements, the graph gradually flattens out. The obtained age datings of the rocks characterize four independent stages of the basement formation – 3,16–3,17; 2,83; 2,71–2,72 and 1,90 Ga, which corresponds to the range from the Lower Lopian Erathem (LP1) of the Upper Archean (AR2) to the Upper Karelian (KR2) of the Lower Proterozoic (PR1).
Keywords: Siberian Platform, basement, geochemistry, absolute age, zircons, U/Pb dating.