The age measures and its layer sequence tratigraphy of Late Quaternary sediment in Lushan Dajiaochang of China

Through the scientific investigation on Lushan for a long time,detailed studies have been carried out on the geologic stratum section of Late Quaternary in Dajiaochang. The series age data of complete stratigraphic section and full time formation since 400 kaBP were based on the results of the analyses using the dating methods with various instruments such as the ancient geomagnetism,electronics spin resonance(ESR),36Cl and luminescence dating,etc. Corresponding to these data,it identified the paleomagnetic polarity events including Biwa-Ⅲ event(320 kaBP),Biwa-Ⅱevent(260 kaBP),Biwa-Ⅰevent(180 kaBP,scarcity due to the disturbance of the iron dish),Blake event(100 kaBP) and Laschamp event(20 kaBP,didn’t grow due to the activities of the surface), etc. Combined with the sequence stratigraphy,layer type characteristics and its sediment environment,the stratigraphic can be divided into 4 stages of development respectively:Stage Ⅰis the climate period of glacial epoch(200~400 kaBP);stage Ⅱis the climate period of interglacial epoch(100~200 kaBP);stage Ⅲis the climate period of periglacial epoch(10~100 kaBP);stage Ⅳis the climate period of postglacial epoch(0~10 kaBP).

Through the scientific investigation on Lushan for a long time, detailed studies have been carried out on the geologic stratum section of Late Quaternary in Dajiaochang. The series age data of complete stratigraphic section and full time formation since 400 kaBP were based on the results of the analyses using the dating methods with various instruments such as the ancient geomagnetism, electronics spin resonance （ESR）, 36C1 and lumines- cence dating, etc. Corresponding to these data, it identified the paleomagnetic polarity events including Biwa- III event （320 kaBP）, Biwa- 1I event （260 kaBP）, Biwa- I event （180 kaBP, scarcity due to the disturbance of the iron dish）, Blake event （100 kaBP） and Laschamp event （20 kaBP, didn＇t grow due to the activities of the surface）, etc. Combined with the sequence stratigraphy, layer type characteristics and its sediment environment, the strati- graphic can be divided into 4 stages of development respectively ： Stage [ is the climate period of glacial epoch （200-400 kaBP）; stage 11 is the climate period of interglacial epoch （100-200 kaBP）; stage llI is the climate peri- od of periglacial epoch （10-100 kaBP）; stage IV is the climate period ofpostglacial epoch （0-10 kaBP）.