增才 唐

The Cretaceous marks the peak of magmatic activity in southeastern (SE) China, which is attributed to the subduction of the paleo-Pacific plate beneath the South China Block. This region constitutes a significant igneous belt along the active continental margin of the western Pacific. Despite extensive research, the origin and evolution of Cretaceous felsic volcanic rocks are still debated. This study investigates the characteristics of zircon U-Pb-Hf isotopes and trace elements, and whole-rock geochemistry of Cretaceous volcanic rocks from the Wenzhou–Taizhou region in SE Zhejiang, and discusses their spatio-temporal patterns and petrogenesis. The results indicate that rhyolitic volcanic rocks formed during the period ca. 114 Ma and 95 Ma, representing two distinct magmatic episodes spanning the transition from the late Early to early Late Cretaceous. The late Early Cretaceous and early Late Cretaceous volcanic rocks are of a hybrid crust–mantle origin, as evidenced by their distinct Nb/Ta ratios, zircon ε_Hf(t) values, and variable trace element enrichments (Ti, Hf, U, Nb, and Yb). These compositional signatures suggest partial melting of late Paleoproterozoic to early Mesoproterozoic basement materials, with increasing mantle contributions over time. Both volcanic phases exhibit elevated Nb/Yb, Th/Nb, and U/Yb ratios, indicating a subduction-modified source akin to arc magmas. Together with calculated initial melt temperatures (800 °C for Late Cretaceous) and whole-rock rare-earth elements (REEs) distribution patterns (U-shaped with δEu = 0.37–0.65, seagull-shaped with δEu = 0.19–0.62, respectively), it is suggested that both phases of the volcanic magmas were generated through water-assisted (hydrous) melting, whereas the later phase formed at relatively higher temperatures and with a diminished water contribution via dehydration melting under extensional conditions. The generation of voluminous high-silica magmas in the SE China coastal region is probably linked to the rollback and retreat of the paleo-Pacific plate.

《地球科学》(ISSN 1000-2383;CN42-1874/P) (原刊名《地球科学——中国地质大学学报》ISSN 1000-2383;CN42-1233/P)，创刊于1957年，是由教育部主管、中国地质大学主办的综合性地学学术理论期刊，月刊，2015年改名为《地球科学》,她以反映中国地质大学教学与科研最新的、高水平的基础地质、应用地质、资源与环境地质及地学工程技术研究成果为主要任务。

《地球科学》(ISSN 1000-2383;CN42-1874/P) (原刊名《地球科学——中国地质大学学报》ISSN 1000-2383;CN42-1233/P)，创刊于1957年，是由教育部主管、中国地质大学主办的综合性地学学术理论期刊，月刊，2015年改名为《地球科学》,她以反映中国地质大学教学与科研最新的、高水平的基础地质、应用地质、资源与环境地质及地学工程技术研究成果为主要任务。