Fluvial landscape change in Anqing through the last glacial cycle: Implications for eustatic controls on the Yangtze River's continental-scale incision-aggradation cycles

Abstract

The Yangtze River is known as the ‘mother river of China’ because it flows through the country's most densely populated and historically wealthiest regions. However, the evolution of the Yangtze River and its controls remain unclear. In this study we dated samples extracted from five bedrock-penetrated boreholes in Anqing, in the lower Yangtze River Valley. The resultant optically stimulated luminescence (OSL) and radiocarbon (14C) dates would suggest that fluvial sediments accumulated during the ∼33–44 ka and ∼11-0.2 ka periods, with extensive erosion during the >44 ka and 33-11 ka timeframes. We also reviewed data from 13 OSL and 14C dated boreholes located between the middle reaches of the Yangtze River and its estuary. The results would suggest that most of the fluvial sediments were deposited during Marine Isotope Stages (MIS) 3 and 1, with a clear erosion hiatus during the Last Glacial Maximum (LGM). Glacial-interglacial cycle-driven eustasy was the main driver of the Yangtze River's incision-aggradation process. The eustatic forcing during the glacial-interglacial cycle influenced the changes in the landscape of the Yangtze River Valley as far inland as ∼1200 km from the present-day shoreline.