Sedimentary Records of the Upper Cretaceous Yetang Formation: Compression Tectonic Setting in the Xingning Basin, Southeastern Edge of the South China Block

Abstract

The southeastern edge of the South China Block (SCB) experienced the subduction of the Paleo-Pacific Block, resulting in varying tectonic settings across different regions of the SCB during the subduction. To explore the tectonic settings during sediment deposition in the southeastern edge of the SCB in the early Late Cretaceous, we analyzed the Jiao Yangjing-Yetang section of the Xingning Basin, Guangdong province. This section contains a sedimentary sequence of the Upper Cretaceous Yetang Formation, facilitating lithofacies analysis, U–Pb zircon chronology, trace elements analysis, crustal thickness estimation, Hf isotopes analysis, and age distribution comparison of detrital zircons. Our findings indicate that the Late Cretaceous Yetang Formation was deposited during the early Late Cretaceous Cenomanian stage (99.6 ± 1.9 Ma), and identifies five groups of detrital zircon U–Pb ages: 2320–1810, 1100–670, 500–400, 230–160, and 130–96 Ma. The early Late Cretaceous ℇ_Hf (t) values ranged from −7.4 to 0.6, suggesting that the debris originated from the southwestern Fujian and northern Guangdong regions. Trace elements analysis of detrital zircons indicates increasing crustal thickness during the early Late Cretaceous. The Xingning Basin was in a compressive environment during the late Early Cretaceous, and the compressive condition continued until the early Late Cretaceous period (99.6 ± 1.9 Ma).