Global patterns of shore platform evolution and cliff retreat: Insights from cosmogenic radionuclides

초록

Rocky coasts are actively evolving geomorphic features whose long-term evolution is critically influenced by Relative Sea Level (RSL) change. Cosmogenic radionuclides (CRNs) offer a powerful tool to quantify these millennial-scale rates of shore platform evolution and cliff retreat. This study synthesizes global CRN research on rocky coasts and presents a detailed case study of the Korean Peninsula, a unique natural laboratory with distinct RSL end-members: the actively uplifting East Coast and the tectonically stable West Coast. Our analysis, incorporating new and re-evaluated 10Be data, reveals contrasting evolutionary patterns. East Coast platforms predominantly show Holocene formation with varied site-specific cliff retreat rates (e.g., Jangsa: 1.4 to 7.0 mm/yr acceleration; Ayajin/Jukbyeon-ri: deceleration). In stark contrast, West Coast platforms exhibit significantly higher 10Be concentrations and "stair-step" profiles, providing strong evidence for widespread interglacial relict surfaces. These findings underscore RSL change as a fundamental long-term boundary condition, interacting with regional tectonics and oceanographic forcing. While CRNs offer invaluable insights, challenges remain in model assumptions and accounting for complex shielding. Future research necessitates enhanced data acquisition, refined process-based modeling, and integrated datasets to improve predictions of rocky coast responses to accelerating sea-level rise.

키워드