Sources of clastic material of the Neoproterozoic metasedimentary rocks of the Baikal–Patom belt, Northern Transbaikalia: Evidence from Sm-Nd isotope data

Abstract

First systematic data on the variations of ε Nd (T) in the Neoproterozoic sedimentary sequence of the Baikal-Patom fold belt (Northern Transbaikalia) are reported. The range of obtained ε Nd (T) is -19.4…-2.0. It was established that the rocks of the Ballaganach and most part of the Dal'nyaya Taiga groups are characterized by ε Nd (T) from -19.4 to -16.3. Upsection, beginning from the Khomolkha Formation, the rocks show a sharp change in the initial Nd isotope composition (ε Nd (T) -8.3…-2.0). The results of Sm-Nd study of metasedimentary rocks of the BPB, as well as the comparison of their Sm-Nd characteristics with those of the inferred source areas suggest that the input of terrigenous material at the early stage of sedimentation in the Baikal-Patom belt was mainly related to the destruction of the Early Proterozoic crust of the Siberian craton. Owing to a change of sedimentation setting from passive continental margin to the "foreland" basin at the late stage, the terrigenous material of the Siberian craton was diluted by clastics from juvenile Neoproterozoic crust of the Baikal-Muya belt.

Structure of the Golets Vysochaishy gold deposit (Northern Transbaikalia)

“…На месторождении Голец Высочайший вмещающие породы представлены высокопластичными терригенно-карбонатными отложениями хомолхинской свиты неопротерозойского возраста (~610 млн лет), накопление которых проходило в условиях спрединга задугового бассейна [Chumakov et al, 2013;Powerman et al, 2015;Chugaev et al, 2017;Budyak et al, 2019].…”