PROVENANCE OF THE HOLOCENE SEDIMENTS IN THE JIANHU GANGXI SECTION AND THE IMPLICATIONS FOR THE DRAINAGE SYSTEM ADJUSTMENT OF THE SUBEI BASIN

The provenance of the Holocene continental deposits in the Jianhu Gangxi Section, as the records of regional change in drainage system, is significant to the understanding of the river system adjustment and the evolution of the Subei Basin, especially to the investigation of the interaction between land and sea. Special attention is paid by the authors to the sources of the Holocene deposits of the Jianhu Gangxi Section using the detrital zircon U-Pb as a tool. The zircon age distribution pattern and the comparison with regional source drainage show that the Quaternary sediments of the Jianhu Gangxi Section could be subdivided into seven age groups: < 200, 200~350, 350~550, 700~1 100, 1 300~1 600, 1 700~2 100 and 2 400~2 600 Ma. As possible sources, the zircon age distribution patterns of the Yangtze River, the Yellow River, the Huai River and the Feihuanghe are rather different. Since the area became land, the Huai River has remained the main sediment source of the Jianhu area and the Feihuanghe has made certain contribution to the sedimentation while the contributions of the Yangtze River and the Yellow River remain negligible.