Quartz Electron Spin Resonance (ESR) Dating of River Terraces in the Zhenjiang River of the Upper Beijiang River

River terraces are important geomorphic indicators that reveal the evolution of rivers, and their climatic and tectonic responses. Dating is key to studying terrace evolution. In the past decade, electron spin resonance (ESR) dating has been widely applied in Quaternary geology and environmental research, and has solved a series of Quaternary chronology problems. This study selected well-exposed river terrace sections of the Zhenjiang River in the upper reaches of the Beijiang River as the research object and used ESR dating to analyze the ages and formation mechanisms of the terraces of the Zhenjiang River system. The experimental data show that the Ti-Li core dose-response curve of quartz in the sediment samples of the Zhenjiang River terraces fits well with the ESR signal strength, indicating that the terrace samples are stable and meet the requirements of ESR dating. Two age data were obtained from the bottom and the top of the ZJ-P1 profile, with ages of 654 ± 79 ka and 231 ± 29 ka respectively; three age data (576 ± 38 ka, 523 ± 55 ka and 256 ± 26 ka) were obtained from the bottom to the top of the ZJ-P2 profile, and three age data (392 ± 56 ka, 132 ± 15 ka and 41 ± 6 ka) were obtained from the bottom to the top of the ZJ-P3 profile, being respectively. These results reflect the continuous sedimentation of the strata. Through the comparative analysis with the existing thermoluminescence age data of the Zhenjiang River and adjacent basins, it is determined that there are two distinct river terraces on the left bank of the Zhenjiang River in the upper reaches of the Beijiang River, and the final formation times of T2 and T1 are approximately 231 ± 29 and 41 ± 6 ka, respectively. Similarly, the ages of the river terraces in the main basins of northern Guangdong obtained by different dating methods were similar, indicating that the rivers in northern Guangdong were generally incised during the Middle and Late Middle Pleistocene and that the main rivers in northern Guangdong have synchronous evolution characteristics. On the basis of sedimentary characteristics of the river terraces in the Zhenjiang section of the upper reaches of the Beijiang River, terrace dating data, and previous research, it is shown that the formation of the second terrace in the Zhenjiang section was mainly influenced by tectonic uplift movements; the final formation time was in the Middle and Late Pleistocene, and the first terrace was formed under the combined action of climate change and tectonic activity during the late Pleistocene. Based on the ages of the samples at the top of the T2 and T1 gravel layers and the incision heights, the corresponding incision rates were calculated to be 0.056 and 0.524 mm/a, respectively. Finally, a comparison with the downcutting rates of other river terraces in neighboring areas showed that the Jinjiang and Zhenjiang Rivers exhibited higher downcutting rates since the Middle to Late Pleistocene, indicating the presence of tectonic uplift in northern Guangdong during this period. This study determined the ages and formation mechanisms of low-level river terraces in the Zhenjiang River section using ESR dating and provides an important reference for the study of climatic and tectonic responses in northern Guangdong.