Late Precambrian terrigenous rocks of the Anamakit–Muya zone of the Baikal–Muya belt: geochemistry and results of LA-ICP-MS dating of detrital zircons

摘要: Abstract A comparative geochemical characteristics of Late Precambrian sedimentary rocks (Ust’-Kelyana and Tuluya rock units) in the Anamakit–Muya zone Baikal–Muya belt is given, conditions their sedimentation are considered. The first results U–Pb (LA-ICP-MS) dating detrital zircons Sm–Nd isotope data on unit deposits presented. Petrogeochemical study showed that studied sediments first-cycle similar composition to terrigenous island-arc sediments. low contents Th, Rb, Zr, Hf, LREE high Co, Ni, Sc, V, Cr, Fe2O3* sandstones Ust’-Kelyana evidence these oceanic-arc deposits. In contrast, enrichment LREE, Nb indicates similarity continental island arcs or active margin. Isotope-geochronological studies mixing material resulted from erosion Neoproterozoic igneous associations (625–700 Ma), like those Karalon–Mamakan (Yakor’ Karalon Formations), more ancient associations, Kelyana (812–824 Ma) and/or Dzhaltuk Groups. Judging minimum age zircon, lower time bound corresponds 0.6 Ga.