Tectonic subsidence of the southeast China coast: New evidence from Late Pleistocene transgression in Ningde bay

Abstract

Subsidence of the ancient Zhejiang-Fujian Uplift (ZFU) is important to understand opening of the Chinese marginal seas and geomorphology of the east China coast. However, little was known about its subsidence history during the Quaternary. In this study we clarify three marine sedimentary layers constrained by luminescence (OSL) chronology in Ningde area of the southeast China coast, to reveal the regional subsidence evolution related to the ancient ZFU. The results show that three marine sedimentary layers above bedrock in Ningde area are formed during global sea-level highstands of MIS1, MIS3 and MIS5e, constrained by OSL datings of the three representative cores. Limited marine influence of MIS5e highstand indicated both by microfacies of the representative cores and by the paleo-shoreline outlined from 120 cores, implies that tectonic subsidence occurs here during the Late Quaternary. The offsets between the peak global sea level and the corrected paleo-shoreline elevations of MIS5e and MIS3 reveal that the average subsidence rate is ∼0.5 m/kyr since MIS5e and ∼ 0.8 m/kyr between MIS5e and MIS3 in Ningde area. This evidence suggests that the ancient ZFU possibly subsided rapidly since MIS5e and stabilized since MIS3. This study provides new insights into the subsidence history of the ancient ZFU and land-sea interaction in the tectonic subsidence region.