Age of Detrital Zircons and Sources of Terrigenous Deposits of the Olokit Zone (Northern Baikal Region)

Abstract

This work presents the results of U–Th–Pb (LA–ICP–MS) geochronological study of detrital zircons from terrigenous deposits of the Olokit zone of the Baikal–Patom fold–thrust belt of the Siberian Craton. It was established that the age of deposits of the Olokit Formation is in the range of 0.86–0.72 Ga. Archean and Early Proterozoic rocks of the southern part of the Siberian Craton and the Neoproterozoic complexes of the Baikal–Muya belt were the sources of detrital zircons of the terrigenous rocks of the Olokit zone. There is no evidence of rocks that could have been the sources of Mesoproterozoic (1.08–1.46 Ga) and Late Paleoproterozoic (1.65 Ga) detrital zircons for the deposits of the Ondok paleo-uplift in the Olokit zone, in the Baikal mountain region, and in the Siberian Craton. The data obtained and the results of paleomagnetic reconstructions indicate that Siberia and Laurentia in the Meso- and Early Neoproterozoic were in a fixed position relative to each other; an unknown continental block composed of Mesoproterozoic rocks could have occupied the space between them.