摘要
The Alax metamorphic block (basement) distributed in the western margin of the North China Craton is mainly composed of Archean Diebusige Rock Group, Paleoproterozoic Bayan-Wulashan Rock Group, Paleo-Middle Proterozoic Alax Rock Group and some orthogneisses. There are some augen and banded gneisses in the Alax Rock Group, which were commonly referred to in the past as the metamorphic strata of Alax Rock Group. However, the authors’ study indicates that these augen and banded gneisses are actually deformed granites (orthogneisses). The discovery of the Early Neoproterozoic granites in this area suggests that the Alax metamorphic basement was reformed by magmatic events of the Early Neoproterozoic orogenesis (Grenville orogenesis).