Mesozoic magmatism and crustal evolution in the Xing’an–Mongolia Orogenic Belt, NE China

Abstract

The Xing’an–Mongolia Orogenic Belt (XMOB), located in the eastern Central Asian Orogenic Belt (CAOB), is a critical area for understanding Phanerozoic crustal accretion and reworking. Its geological record reflects the combined influence of Paleozoic ocean closure and extensive Mesozoic overprinting linked to the subduction of the Mongol–Okhotsk and Paleo-Pacific plates. This study integrates published geochronological, geochemical, and zircon Hf isotopic data to investigate the spatiotemporal patterns and petrogenesis of Mesozoic magmatic rocks in the XMOB, focusing on the Ergun and Xing’an blocks. The results suggest that the region’s Mesozoic magmatism was primarily driven by tectonic transitions associated with the closure of the Mongol–Okhotsk Ocean and rollback of the Paleo-Pacific slab. Isotopic evidence reveals distinct crustal processes in the two blocks, with vertical crustal reworking dominating in the Ergun Block and lateral crustal growth in the Xing’an Block. These findings shed new light on the tectono-magmatic evolution of northeastern China and contribute to broader understanding of continental crustal development in the eastern CAOB.