The Study on Characteristics of Slackwater Deposits of Palaeoflood Sedimentary in the Loess Regions

Analysis of slackwater sediments has become a widely accepted in palaeoflood research. The identification the palaeoflood deposits are important for the study of palaeoflood. This paper reports the identification of the palaeoflood slackwater sediments in the Holocene loess profile in the loess region. We measured the magnetic susceptibility, clay content, CaCO3 and clay/silt ratio, in the HXZ- E profile,Qishuihe River Valley and compared with the loess accumulation. The results show that indexes in the palaeoflood deposits except the third deposit are between the soil and the loess accumulation. These indicate the palaeoflood deposits have the weak pedogenic. Through the research of these indexes we can identity the palaeoflood slackwater sediments from the loess accumulation. This research result is not only practical to the flood control, water resources exploitation and eco- environmental construction for Yangling, a well- known agricultural and high- tech city in River Basin, but scientificly significant to the comprehensive improvement of the eco- environment of the river basin.