U-Pb isotopic geochronologic investigations of zircons from granites and ore-bearing metasomatites of the Berezitiovoe gold-polymetallic deposit (Upper Amur region)

• Published in: Russian journal of Pacific geology Vol. 7; no. 6; pp. 384 - 402
• Main Authors: Vakh, A. S., Avcheko, O. V., Kiselev, V. I., Sergeev, S. A., Presnyakov, S. L.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-11-2013; Springer Nature B.V
• Subjects: Earth and Environmental Science; Earth Sciences; Geological time; Geology; Gold; Granite; Metamorphic rocks; Paleozoic; Stratigraphy; Studies; Russia; isotopic geochronology; zircon; granite; Upper Amur region; gold-polymetallic deposit; U-Pb method; North Asian craton
• ISSN: 1819-7140; 1819-7159
• DOI: 10.1134/S1819714013060067

The results of the U-Pb geochronologic studies of zircons from the ore-bearing metasomatites of the Berezitovoe deposit in the Upper Amur region and the porphyroid biotite-hornblende host granites of the Khaikta-Orogzhan massif, which were previously considered as Early Proterozoic magmatic formations of the Late Stanovoi Complex, are examined. The SHRIMP-II and LA-ICP-MS methods were used for this purpose. It was revealed that the mass spectrometer method coupled with a laser ablation system yields precise U-Pb rock dating, and its results are comparable with the data obtained by the SHRIMP-II method. The weighted average isotopic ages are 344–355 and 323–366 Ma as established for the zircons from the porphyroid granites of the Khaikta-Orogzhan massif and from the ore-bearing metasomatites of the Berezitovoe gold-polymetallic deposit, respectively. The data definitely indicate that the metasomatites were developed after the granitoids of the Khaikta-Orogzhan massif and belong most likely to an autonomous Late Paleozoic magmatic complex. Coeval Paleozoic magmatic complexes are widespread within the Selenga-Stanovoi superterrane in the eastern and western Transbaikal regions.