Super paleo-typhoons striking southern Hainan Island in the northern South China Sea during the mid-late Holocene: Coral boulder evidence from a fringing reef

Abstract

Hainan Island, situated at the northern margin of the South China Sea, is highly vulnerable to typhoon impacts, particularly super typhoons, which have caused catastrophic damage. Despite their persistent threats, research on these extreme events remains limited. At the Xiaodonghai Fringing Reef (XFR) in southern Hainan Island, coral boulders (CBs) distributed across the reef flat are interpreted as typhoon-transported features, serving as proxies for reconstructing past typhoon activity. This study establishes the relationships between (1) typhoon landfall wind velocities and wave heights along the South China and East China coasts, and (2) the mass of CBs on the XFR reef flat and their inferred typhoon wave heights. Utilizing these relationships, nine CBs were identified as having been transported by super typhoons. Through field positioning, radiometric dating, and comparisons with modern typhoon records, we identify five distinct phases of super paleo-typhoon (SuperPTY) that struck southern Hainan Island during the mid-late Holocene: 6970–6310 cal. aBP, 5890–5840 cal. aBP, 2490–1890 cal. aBP, 1630–1600 cal. aBP, and 1490–1450 cal. aBP. Notably, no super typhoons impacts have been recorded in recent decades. These SuperPTY phases correlate with atmospheric-oceanic teleconnections driven by the El Niño-Southern Oscillation and the Pacific Decadal Oscillation, as well as regional sea level fluctuations—factors that may also influence future super typhoon activity around Hainan Island under global warming. Further investigations into high-resolution sedimentary archives are recommended to advance understanding of spatiotemporal patterns in super typhoon occurrence.