Optically stimulated luminescence dating of sediments from the Yellow River terraces in Lanzhou: Tectonic and climatic implications

Abstract

The stratigraphic chronology of Yellow River terraces was investigated and studied in Lanzhou Basin, western Chinese Loess Plateau. The optically stimulated luminescence (OSL) dating results show that terraces T 1, T 2 and T 3 formed at 8 ka, 20 ka and 70 ka, respectively. Lateral accretion of the riverbed facies gravel sediments occurred during interglacial periods while vertical aggradations of the terrace sediments deposited predominantly under cold and dry glacial period. A thick layer of aeolian loess with a basal age about 35 ka indicates a remarkable drop of air temperature and a dry, cold climate. The temporal correlation between terrace formation and tectonic movement has not yet been established in this research, but the stratigraphic chronology of the terrace sections provides the timing of the terrace formation, the incision rate of the Yellow River, and the slip rate of the fault horizon.