Late Cretaceous-Paleogene rift initiation of the southwestern East China Sea Basin: Implications from a fission-track study of the Changle–Nan’ao Belt

•A rapid cooling/exhumation event occurred in the Changle-Nan’ao Belt during the period from 80 to 70 Ma.•The Changle–Nan’ao Belt behaved as a single tectonic unit since 70 Ma.•Rifting started in the southwestern East China Sea and propagated southwards to the northeastern and then northwestern South China Sea during the Late Cretaceous-Paleogene.