粤东沿海地区海蚀遗迹分布及宇宙成因核素测年分析OA

The tectonic activity since the Late Pleistocene plays a critical role in evaluating crustal stability in the coastal areas of South China.Previous studies have systematically examined the relationship between sedimentation and faulting in subsidence zones,whereas uplift areas have received limited attention due to dating constrains.Cos-mogenic nuclide dating effectively resolves the chronological challenges in uplift regions.This study investigates ma-rine erosional landforms along the eastern Guangdong coastal zone,focusing on granite-based marine terraces in Zhelang,Shanwei.By determining the exposure ages of four marine terraces using cosmogenic nuclides,we quan-tify the differential movement rates in uplift areas.The results reveal that the four marine terraces correspond to modern sea level,the Holocene highstand,and paleo-sea levels during MIS3 and MIS4.The elevation differences between paleo-sea levels and contemporary terraces indicate tectonic uplift in Shanwei since MIS4.The maximum uplift exceeding 100 m since MIS3 yields an average rate of～2 mm/a,consistent with current uplift rates observed in the southwestern Pearl River Delta.Similarly,a local average uplift of 106 m since MIS4 corresponds to a rate of～1.5 mm/a calculated over 70 ka,aligning with uplift rates derived from the Shipai Formation in the Pearl River Delta.These results reveal that the basement faults(blocks)in the Shanwei area have exhibited relatively pro-nounced activity characteristics since the Last Glacial Period.These findings provide an important geological refer-ence for assessing the safety of the Shanwei urban area and the neighboring city clusters of the Guangdong-Hong Kong-Macao Greater Bay Area,and should be given high priority in regional stability evaluations.