The Climate And Environmental Evolution Since The Mid-Holocene In Tangwang, Qingzhou Of Shandong

The climate of Holocene is complex,with several large fluctuations,but the response to climate changing in different region,also is the transition zone of sea and land, and is a perennial activities of East Asion monsoon. Study of the lake sediments in Shandong is few,and it is no conducive to recover the ancient climate of Shandong. Therefore,the article analysis of the climate evolution in this area by the characteristics of sediment grain size,combined with magnetic susceptibility、color、carbonate dates.The section from Tang wang located in Shangdong of Ji′nan city. Using Tangwang sediment grain size、magnetic susceptibility and sediment color to recover the changes of climates and environment in Shangdong,and combined with AMS14 C dating from the profile to establish the time frame. The results shows that:The sediments of profile are mainly composed by silt and clay,silt is the highest,the particle size of sediments shows relatively smooth change. Frequency curve of the sediments perform unimodal and bimodal peaks. 5580 cal a BP ~4620cal a BP,This stage was composed by fine particles and the dating of magnetic susceptibly is lower,the effective humidity was lower, performed by cold and dry climate;4620cal a BP~4045cal a BP the fine particles and magnetic susceptibly showed an increasing,the proxies had an character of low sediment color L*、a* and b*,which showed the climate was warm and wet,effective humidity was high and lake level was high;4045cal a BP~2830cal a BP which was inferred from the higher magnetic susceptibly 、 fine particles and lower a* and b*indicated a higher lake level,the climate was warm and wet;2830cal a BP ~960cal a BP the proxies were fluctuated obviously, which indicated that the climate changed repeatedly, and showed cold and wet climate alternately;From 960 cal a B.P. the lake gradually degraded. The proxies had a higher a* and b*, which showed the climate was dry. The climate environment of Shangdong had experienced dry and cold- wet – worm and dry alternated – cold and dry.