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Based on field landscape investigations,thermoluminescence(TL),magnetostrati-graphy and loess-paleosol sequence,we found that there are at least four Yellow River ter-races,whose ages are 0.86 Ma,0.62 Ma,0.13 Ma and 0.05 Ma,in Yuxi Fault-Uplift(from Sanmen Gorge to Mengjin) and at least three Yellow River terraces,whose ages are 1.24 Ma,0.25 Ma and 0.05 Ma,in Huabei Fault Depression(from Mengjin to Kouma).All the terraces have a similar structure that several meters of paleosols directly develop on the top of fluvial silt.It shows that the Yellow River incised and consequently abandoned floodplain converted to terrace during the interglacial period.Therefore,there may be a link between the formation of terraces and glacial-interglacial climatic cycles.However,the differences in the Yellow River terrace sequences and ages between Yuxi Fault-Uplift and Huabei Fault Depression indicate that the surface uplift should play an important role in the formation of these terraces.
Based on field landscape investigations, thermoluminescence (TL), magnetostrati-graphy and loess-paleosol sequence, we found that there are at least four Yellow River ter-races, whose ages are 0.86 Ma, 0.62 Ma, 0.13 Ma and 0.05 Ma, in Yuxi Fault-Uplift (from Sanmen Gorge to Mengjin) and at least three Yellow River terraces, whose ages are 1.24 Ma, 0.25 Ma and 0.05 Ma, in Huabei Fault Depression (from Mengjin to Kouma). All the terraces have a similar structure that several meters of paleosols directly develop on the top of fluvial silt. It shows that the Yellow River incised and unsuited floodplain converted to terrace during the interglacial period.Therefore, there may be a link between the formation of terraces and glacial-interglacial climatic cycles .Wowever, the differences in the Yellow River terrace sequences and ages between Yuxi Fault-Uplift and Huabei Fault Depression indicate that the surface uplift should play an important role in the formation of these terraces.