The first U-Pb (SHRIMP-II) evidence of the Franklin tectonic event at the western margin of the Siberian craton

Geochemical and isotope-geochronological evidence of the manifestation of Late Riphean intraplate magmatism within the Chernorechensky massif at the western margin of the Siberian craton were obtained. These rocks crystallized from high-temperature and anhydrous (water unsaturated) magmas with high concentrations of alkalis, iron, and, mostly incompatible elements, which is typical for anorogenic A-type granites in intraplate extension setting. Their U-Pb zircon age 723 ± 6 Ma can be correlated with the Franklin rift event widely manifested in the north of Laurentia, associated with the breakup of Rodinia. The synchronous successions and similar style of magmatic activity and concomitant rifting, as well as a similar sequence of tectonic-thermal events along the Arctic margin of Rodinia support the spatial proximity of Siberia and the North Atlantic cratons at this time as proposed for the paleogeographic reconstructions.