572 / 2024-09-18 13:53:15

Evolutionary history of the sandy coast in South China from the Middle-Late Pleistocene: A case study from Lufeng, China.

sediment-starved coast;,Sea level change,Sediment sources,Middle-Late Pleistocene

Session 27 - Coastal environment evolution : from the past to the future

The coastal zone is the area where land-sea interactions are most intense, and coastal zones without large river inputs represent the largest areas of land-sea interaction. Based on core along the coast of the Twelve Lakes in Lufeng, an age model was constructed using optically stimulated luminescence (OSL) dating and accelerator mass spectrometry radiocarbon dating (AMS ¹⁴C). In combination with ground-penetrating radar (GPR), sediment grain size, and elemental geochemical indicators, methods such as end-member analysis (EMA) and empirical orthogonal function (EOF) analysis were employed to identify changes in depositional facies and sediment sources. These study results indicate that sediments mainly originated from transport by small rivers in the surrounding area, and the sandy coasts of southern China have experienced multiple marine transgression events since the Middle-Late Pleistocene: The first phase (MIS 6 or earlier) records variegated clay deposits from a period of terrestrial exposure and weathering during a low sea level; The second phase (MIS 5e~ MIS 5d) reflects shallow marine deposition during the high sea level stage of the last interglacial period in an opening embayment, environment; The third phase (from MIS 5c to the present) records terrestrial aeolian and beach deposits in an environment lacking direct sediment supply. This evolutionary model suggests that glacial-interglacial cycles and sea-level changes are the main controlling factors for the evolution of sandy coasts.