关键词: 二里头遗址, 异常洪水, 粒度, 磁化率, 相关分析

Abstract: A fluvial sediment profile was found in the south of Erlitou Site, Luoyang Basin, locating in the frontier lines of terraceⅡ. The OSL dating, magnetic susceptibility analysis and grain size analysis were taken. It is showed that the depositional age of the profile is between 2000?5000 aBP. The profile can be divided into three sections: the lower section (113?123 cm) is with fine grain size and high magnetic susceptibility, and the grain size curves indicated flood plain environment, showing floodplain deposits; the middle section (90?113 cm) is with coarse grain size and low magnetic susceptibility, and the grain size curves indicated boundary beach-flood plain environment, showing riverbed-boundary beach deposits; the middle section (0?90 cm) is with fine grain size and high magnetic susceptibility, and the grain size curves indicated flood plain environment, showing floodplain deposits. It is found that the middle riverbed-boundary beach deposits covered on the Longshan ash pit of the terraceⅡ, which records a great flood spreading over the river terrace. This flood is significantly correlated with the pollen analysis result. The 4000 aBP abnormal flood and the changes of the river might be regional responses of the 4200 aBP global abnormal climate event. The location of Erlitou city site might be greatly influenced by the flood event.

Key words: Erlitou Site, paleoflood, grain size, magnetic susceptibility, correlation analysis