Residual dose of quartz Optically Stimulated Luminescence signals in modern sediments of the Yellow River Basin
The Optically Stimulated Luminescence(OSL)dating of modern fluvial sediments is important for building of accurate luminescence chronology and understanding fluvial geomorphological evolution and erosion-deposition processes.The complex sediment sources and deposition processes of the Yellow River highlight the systematic understanding of the modern OSL residual doses throughout the entire river basin.Here,equivalent doses of modern quartz of different grain sizes and from different reaches of the Yellow River were measured.The results showed distinct residual doses among different grain sizes of quartz.Coarse-grained quartz exhibited most sufficient bleaching(average 5.0 Gy),while fine-grained quartz showed the poorest bleaching(average 14.6 Gy),with a maximum residual dose of 52.8 Gy(approximately equivalent to 20 ka).Moreover,regional variations were observed in the bleaching levels of quartz of different grain sizes.In the source region of the Yel-low River and Tongguan-Huayuankou reaches,the residual doses of coarse-grained quartz(1.5-6.9 Gy)were smaller than that of medium-grained quartz(2.6-23.9 Gy).However,the residual doses of medium-grained quartz in reaches between the Lanzhou to Jin-Shaan Gorge reach(0.4-1.0 Gy)and Jinan to Yellow River Estuary(about 1.2 Gy)were smaller.Furthermore,the residual doses of different grain sizes tended to decrease with in-creasing transport distance in the lower reaches of the Yellow River.These results indicate that the residual doses of modern sediments in the Yellow River Basin may be controlled by factors such as sediment source,transport mode,and transport distance.Such complex mechanisms highlight the necessity of residual dose analyses for specific river reaches and grain-size fractions.
modern sedimentsresidual dosesquartzOSL datingYellow River
NETL
NSTL
万方数据
