New Insights into Geoheritage and Modern Human Activity in Xiqiaoshan, Guangdong Province, Over the Past 40‒50 ka

Between 1958 and 1999, notable lithic localities recorded prehistoric activities in Xiqiao Town of Nanhai District, Foshan City, Guangdong Province, from which double-shouldered and microlith-stone artefacts were uncovered. Currently, the "Xiqiaoshan site" is recognized as a substantial Neolithic quarry and processing location, dating back to 4‒7 ka B P. Subsequently, from 2011 to 2022, we conducted multiple geological environmental surveys and analyses on Xiqiaoshan Mountain. A well-preserved Quaternary stratigraphic profile was discovered north of Fuxian village in the southeast foothills of Xiqiaoshan Mountain. The sedimentological, geochemical, and geochronological results indicate the presence of two primary sedimentary strata in the Fuxian locality. The upper unit comprises the Holocene swamp facies, with a calibrated AMS14C dating range from 5052‒5409 a B P; whereas, the lower unit comprises the late Pleistocene alluvial-diluvial strata, with a calibrated AMS14C dating range from 38420‒40502 a B P, and an optically stimulated luminescence (OSL) dating range of 41.977‒43.796 ka B P. Late Pleistocene strata yielded two sand-gravel layers containing Paleolithic artefacts, which are marked as layers A1 and A2. The predominant artefacts in lower layer A1 include larger scrapers, pointed tools, tongue-shaped edged tools, and small flake tools, such as various scrapers, denticulates, notches, knives, utilized flakes, and cores, including tanged axe-shaped knives. In the upper layer A2, backed or tanged knives appear more frequently. The other small flake tools from this layer (A2) were not significantly different from those in lower layer A1. One bifacially prepared core for producing small elongated flakes is of particular interest for this artefact. Based on the average deposition rate, the computational age of the A1 layer was 46.511‒47.325 ka B P, whereas that of the A2 layer was 41.977‒42.167 ka B P. Although the number of artefacts within the Holocene sediments (>5 ka B P) overlying the late Pleistocene strata is limited, the characteristics of inheritance and development are still evident in the types of artefacts. The discovery presented in this study has completely updated and extended the connotation of Xiqiaoshan National Geopark and "Xiqiaoshan culture,"breaking through the late Pleistocene Paleolithic remains records with exact dating in the Pearl River Delta region for the first time. Therefore, a ground-breaking discovery can accurately trace the footsteps of modern humans in the coastal areas of South China from 40‒50 ka. It also reveals the rich features of lithic industry and the developmental characteristics and evolution of its cultural connotations during this period. The present study shows that during the relatively warm and humid conditions of marine isotope stages 3 (MIS3) interglacial period and the subsequent cold and arid stage of MIS2, human population in the Fuxian locality encountered environmental challenges and adopted new subsistence strategy, which is of great significance for understanding modern human responses and adaptations to global and regional environmental and climate change.