Exhumation of an Archean Granulite Terrane by Paleoproterozoic Orogenesis: Evidence from the North China Craton.

This article focuses on the petrology, geochronology, and metamorphic history of metadiabase dikes within an Archean granulite terrane of the North China Craton (NCC), providing insights into the crustal evolution and reactivation of Archean cratons. U–Pb dating of zircon, titanite, and rutile indicates that the metadiabase dikes were emplaced around 2.4 billion years ago (Ga) and underwent granulite-facies metamorphism at approximately 1.87 Ga, followed by retrograde decompression and cooling during the Paleoproterozoic. Garnet coronae formed between clinopyroxene and plagioclase at peak conditions of ~800°C and 10–13 kbar, with thermodynamic modeling showing that garnet growth required increasing pressure and temperature rather than isobaric cooling. The study concludes that Paleoproterozoic orogenic events, including crustal shortening and thickening linked to the underplating of the Khondalite series during the assembly of the supercontinent Columbia, caused burial, metamorphism, and subsequent exhumation of the Archean basement to mid-crustal levels (~15 km). This metamorphic overprint and exhumation pattern observed in the NCC aligns with similar dual-stage metamorphic histories documented in other global Archean granulite terranes.