A Study of Orogenic Processes: The Tectonic Evolution of the Eastern Central Asian Orogenic Belt

Abstract The Great Xing'an Range (GXR) is a critical contentious region within the eastern Central Asian Orogenic Belt (CAOB), recording complex interactions among the Paleo‐Asian, Mongol‐Okhotsk, and Paleo‐Pacific Oceans since the Paleozoic. The well‐exposed metamorphic and deformed rocks in Keluo Complex (KC) provide important information for its evolutionary history. Our comprehensive analysis reveals a distinct NE‐SW trending zonation of the KC, with significant tectonic activity. These rocks feature ductile shear slip deformation and plastic deformation in minerals like quartz and feldspar, characterized by right‐lateral shearing as the core kinematic signature. EBSD quartz C‐axis fabrics indicate deformation temperatures of 500–600°C (prismatic < a > slip) and 300–400°C (rhomb < a > slip), recording multiple phases of deformation. Zircon U‐Pb dating yields Late Paleozoic protolith ages, while biotite 40 Ar/ 39 Ar dating (133.9 ± 1.34 Ma) constrains the timing of the deformation‐related cooling event in the Early Cretaceous. Combined with regional data, we demonstrate that the uplift of the GXR was primarily controlled by crustal extension triggered by the closure of the Mongol‐Okhotsk Ocean, with subsequent overprinting by the subduction rollback of the Paleo‐Pacific Ocean. The newly constructed tectonic model provides key constraints on multi‐ocean tectonic transition and orogenic mechanisms in the eastern CAOB.