U-Pb isotopic geochronologic study of zircons from granites and ore-bearing metasomatites of the Berezitovoe gold-polymetallic deposit (Upper Priamurye, Russia)
Results of the U-Pb geochronologic studies of zircons from ore-bearing metasomatites of the Berezitovoe gold-polymetallic deposit of Upper Priamurye and the porphyry-like biotite-hornblende host granites of the Khaiktin-Orogzhan massif earlier thought to be Early Proterozoic magmatic formations of the Late Stanovoy Complex are examined. The studies were carried out by two methods: SHRIMP-II and LA-ICP-MS. It was revealed that Mass Spectrometer method coupled with laser ablation system enable precise U-Pb age dating of the rocks and the results obtained are comparable with the data obtained with the help of SHRIMP-II. Established weighted average isotopic ages of zircons are 344–355 Ma from porphyry-like granites of the Khaiktin-Orogzhan massif and 323–366 Ma from ore-bearing metasomatites of the Berezitovoe gold-polymetallic deposit. The data definitely indicate that the former were formed from granitoids of the Khaiktin-Orogzhan massif which are assumed to relate to an independent Late Paleozoic magmatic complex. Close-in-age Paleozoic magmatic complexes are widespread within the Selenga-Stanovoy superterrane in the Eastern and Western Transbaikalia.