Detrital zircon evidence for Gondwana accretion in the northwestern Yangtze Block

The Yangtze Block occupies a key paleogeographic position during the Ediacaran-Cambrian period. Nevertheless, its paleogeographic location and tectonic setting in global plate reconstructions for this timespan remain controversial. In this study, Ediacaran–lower Cambrian siliciclastic samples from the northwestern Yangtze Block were analyzed using detrital zircon U-Pb geochronology and trace element composition, complemented by regional geochronological datasets. Our results suggest a tectonic regime transition from extension to compression at Ediacaran–early Cambrian time. The appearance of ∼1.0 Ga and 0.7–0.5 Ga zircon age groups in the lower Cambrian strata records changing sediment provenance during Gondwana amalgamation. Provenance shifts and crustal evolution suggest a rapid paleogeographic reorganization of the Yangtze Block, linked to the assembly of Gondwana. Detrital zircon trace element signatures are compatible with a passive to convergent margin transition, synchronous with East Gondwana accretion. The northwestern Yangtze Block experienced rapid uplift and coarse clastic influx at ∼520 Ma, suggesting progressive incorporation into the Gondwana margin system