Sedimentary response of the superposition of two major tectonic systems on the southern margin of the South China Block during the Late Triassic

To confirm the potential provenance and the dynamic mechanism of basin evolution of the southern margin of the South China Block in the Late Triassic, we choose the Mashui Town section in Yangchun, western Guangdong as the study area. This article uses whole-rock geochemical analyses, sandstone detrital mode, detrital zircon ages, trace-element composition and basin provenance of the Late Triassic Xiaoping Formation to conclude that the southern margin of the South China Block was deposited in a complex tectonic setting during the Late Triassic. The detrital zircons of the Late Triassic Xiaoping Formation have major age groups of 1150–815 Ma, 550–340 Ma, and 300–220 Ma. We suggest that the detritus probably was recycled form the Proterozoic basement and derived from the Phanerozoic Wuyi Terrane, Yunkai Terrane, and Hainan Island area. The complex tectonic setting has both the characteristics of a peripheral foreland basin and an active continental margin, reflecting its superposition influence by the two major tectonic systems of the Paleo-Tethys Ocean and the Paleo-Pacific Ocean.