Abstract:

The ecological environment and land desertification issues in the vicinity of Poyang Lake are increasingly severe， posing significant constraints on regional economic development. While research on the northeastern Poyang Lake has been progressively undertaken， investigations in the southern Poyang Lake remain incomplete. Particularly， the question of whether the sand dunes in the southern area were transported from distant sources or accumulated from nearby origins during the Last Glacial Period remains unresolved. The Houtian sand dunes in the southern Poyang Lake present an ideal location for studying material sources due to their well-established timing of deposition and continuous sedimentation. This study conducted U-Pb age analysis on six detrital zircon samples from the Houtian section， spanning from the Last Glacial Period to the present， resulting in a dataset of 512 valid zircon U-Pb ages. Analysis outcomes reveal that the most prominent peak in detrital zircon U-Pb ages within the sand dune samples is approximately 830 Ma， followed by around 430 Ma， corresponding to the tectonic-magmatic thermal events during the NeoProterozoic Jinning period and the Early Paleozoic Caledonian period. MDS analysis further confirms a strong correlation between the primary peak of the samples and magmatic rocks in the Jiuling region of the eastern segment of the Jiangnan orogenic belt， while the secondary peak exhibits good affinity with sand sediments from the Ganjiang River. Therefore， the provenance of the study area is mainly derived from the mixture of sediments from nearby Jiuling Mountain and Ganjiang. The formation mechanism is that the water level decreased during the dry period of the Last Glacial period， which led to the flood plain and bare surface of the banks of the Ganjiang River tributaries and the main stream of the Ganjiang from Jiuling Mountain， and the strong winter wind was transported to the river terrace for a short distance.

Key words: sand hill, zircon U-Pb dating, provenance tracing, southern Poyang Lake