Beach Sediments from Northern South China Sea Suggest High and Oscillating Sea Levels During the Late Holocene

Understanding the history of the late Holocene sea level change is critical for predicting the potential effects of future sea level changes. The coral reef region of the Leizhou Peninsula, in the northern coast of the South China Sea, is an ideal site for studying the Holocene sea level history because of its tectonic stability and the possession of numerous prehistoric sea level indicators. The paleobeach sedimentary records from the Leizhou Peninsula indicated a higher-than-present sea level stand, from 1.7 to 1.2 Cal. ka BP (or 14C ages from 2.1 to 1.7 ka BP), which was punctuated by a short-term drop in the sea level at ∼1.5 Cal. ka BP. At 1.2 Cal. ka BP, the sea level was at least 128 cm higher than the present level. After that time, the sea level fell significantly resulting in the retreat of the coastline by ∼210 m and the formation of the modern beach-sand bank geomorphic system. Additional evidence from the coral reef records at this site suggested that similar to the climate change, the sea level also oscillated in the millennial-, centennial-, and interdecadal-scale cycles over the mid-late Holocene.