Cenozoic Tectonothermal History of the Pearl River Mouth Basin, Northern South China Sea: Insights from Fission Track and Seismic Data

Abstract

Quantifying the timing and amplitude of multiple subsidence or uplift stages in sedimentary basins is crucial for understanding their tectonic evolution. In this study, 18 samples from 10 drilling wells in the Pearl River Mouth Basin (PRMB) were subjected to apatite and zircon fission track analyses, and suitable samples were selected for thermal history simulation using Hefty. The thermal history simulation results, combined with balanced cross-section analysis, constrain the Cenozoic tectonothermal history of the PRMB. The results indicate that the PRMB underwent differential uplift in the early Paleogene, followed by regional thermal subsidence in the late Paleogene. Subsequently, the PRMB began tectonic activation in the late Miocene due to the Dongsha movement, marked by two rapid cooling events of ca. 11–6.5 and 6.5 Myr to the present. These cooling events are characterized by a gradual migration from east to west. The first rapid cooling event can be attributed to the NW-SE compressive stress field in the northeastern South China Sea, driven by the clockwise rotation of the Philippine Sea Plate during the late Miocene. The second rapid cooling event is linked to intensive arc-continental collision and the Taiwan Orogeny triggered by the rapid WNW-ward migration of the Philippine Sea Plate.

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