RESPONSES OF MACROELEMENTS TO PROVENANCE CHANGES LAST CENTURY IN THE YALU RIVER ESTUARY

In order to reveal the response of sediments to provenance changes last century in the Yalu River estuary, macroelement composition analysis was performed for 21 samples taken from the Core YLJ-40 collected at the west-branch of the river. For the purpose of comparison, 31 surface sediment samples taken from the adjacent shallow sea and provenance zones were also determined. Based on the results of Q cluster analysis, the vertical variation analysis of macroelements, and the discrimination function calculation for each layer of the core as well as the samples from the provenance zones, the sedimentary records of the West-branch of the Yalu river can be divided into two sedimentary units and five time intervals, which is consistent with previous studies. In addition, Floodings, most probably caused by typhoons, happened in the Yalu River estuary in 1932, 1977, 1983, 1985, and 1995 also left their footprints in the records, which can be used as supplementary dating markers to verify the ²¹⁰Pb dating data. The analysis of discrimination function further confirmed that the lower unit of the core was the fluvial deposits of the Yalu River, while the upper unit was primarily shoal deposits of the resuspended sediments in shallow sea occasionally with some river deposits from the Yalu by extreme events, such as flooding or typhoons.