Geochemistry, petrology, and the tectonic evolution during the Middle Permian-Early Triassic in South Yellow Sea and East China Sea

The Yangtze Plate (YP) and the North China Plate (NCP) are key components of the East Asian continent, and their collision significantly influences the tectonic evolution of the eastern Asian continental margin. As the South Yellow Sea is located at the convergence of these plates, it becomes a pivotal area for understanding the tectonic evolution of East Asia. The characteristics and provenance of clastic rocks of the Middle Permian-the Early Triassic were analyzed and the strata in the Central Uplift including the Qinglong Formation (T1q) and Talung Formation (P3d), consisting of various mudstones and sandstones, were anatomized. Results show that quartz and feldspar are the main diagenetic minerals, while illite and chlorite show signs of secondary alterations. Geochemical imprints indicate a gradual shift in provenance from ancient sedimentary and mafic igneous rocks to intermediate igneous rocks. In the meantime, the tectonic background transformed from continent to continental island arc from the Middle Permian to the Early Triassic. Therefore, we inferred that a soft collision between the North China Plate and the Yangtze Plate likely occurred during the Late Permian, resulted in intensified collision between two plates in the Early Triassic, and shaped the South Yellow Sea. This study provided valuable information on the timing of plate collisions in the South Yellow Sea.