Holocene paleoshoreline changes of the Red River Delta, Vietnam

Abstract

The Red River Delta (RRD), one of the two largest deltas in Vietnam, has been severely affected by natural hazards induced by global climate change. Understanding the Holocene paleoshoreline is crucial in developing adaptive planning in response to future shoreline changes based on past natural shoreline changes. This study presents new data pertaining to pollen, grain size, lithological characteristics, and 14C dating of six cores from the RRD. The purpose of this study was to determine the paleoenvironments and paleoshorelines of the RRD in the Holocene to provide information useful for modeling future changes, e.g., for calibration sea level in paleobathymetry and sea level change models; for making the necessary ecological and cultural adaption to survive. We identified 4 units and 10 sedimentary facies indicating periods of sedimentary evolution since late Pleistocene. The main indicators for paleoshoreline interpretation are true mangrove and backmangrove pollen. The inferred paleoshoreline changes and five paleogeographic maps for 10.5, 9.2, 7.8, 6.5, and 3.7 cal. kyr BP were constructed based on paleoshoreline indicators, and paleoenvironmental reconstructions from the dataset of our whole RRD study area.