Abstract

This article presents the results of U–Pb geochronological study of gneiss-granites of the Mamskaya zone. The age estimate of 1874 ± 9 Ma (SIMS method) obtained for the magmatic protolith of gneiss-granites for the first time proves the close formation time of gneiss-granites from the Mamskaya zone and rapakivi-like granites of the Kodar complex in the Chara–Olekma block. In the Late Devonian and Carboniferous, according to preliminary data, the Paleoproterozoic protolith of the gneiss-granites underwent deep metamorphic processing during shear deformations and formation of pegmatoid granites and pegmatites.

中文翻译：

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Mamskaya 带（贝加尔湖-Patom 带）片麻岩-花岗岩的古元古代时代：地质意义

摘要

本文介绍了对 Mamskaya 区片麻岩-花岗岩的 U-Pb 年代学研究结果。首次获得的片麻岩-花岗岩岩浆原岩年龄估计为1874±9 Ma（SIMS法），证明了Mamskaya带片麻岩-花岗岩与Chara区Kodar杂岩的类rapakivi花岗岩形成时间相近– Olekma 块。在晚泥盆世和石炭世，初步资料表明，片麻岩-花岗岩的古元古代原岩在剪切变形过程中经历了深层变质作用，形成了伟晶岩和伟晶岩。