Sedimentary Record Of Environmental Evolution Since 18 Cal Ka BP Ago In Wusulangzi Lake, Inner Mongolia

Wusulangzi Lake located in the monsoon’s boundary zone in North China and it is very sensitive to the climatic change and environmental evolution. A 623cm long core from Wusulangzi Lake, situated in northeast Inner Mongolia, was used to reestablish the climate changes and environment evolution since the last 18 cal ka BP.The chronological framework was built on 210Pb and AMS14C ages. On basis of grain size distribution, magnetic susceptibility, dry density, sediment color and organic geochemistry six environmental stages can be recognized.First stage (17850-13700 cal a BP), this period is characterized by a dry and cool climate with low Lake level, and the environment is not suitable for the growth of vegetation. This period responds to late glacial climate.Second stage (13700～12850 cal a BP), the climate mainly tended to warm and humid with high Lake level and luxuriant growth of vegetation. This period may have corresponded to the Allerad warm stage.Third stage (12850～11000 cal a BP), the climate became dryer and colder with lower Lake level. This period may have corresponded to the Younger Dryas event.Fourth stage (11000～6600 cal a BP), the climate mainly became warmer and with the slightly of cold and dry oscillations. During the former stage (11000-7900 cal a BP),the temperature has increased. In specialthe climate is characterized by an abruptly increase in precipitation during 11000-10580 cal a BP. during the latter stage (7900～6600 cal a BP), the climate mainly tended to warmer and humid.Fifth stage (6600～4000 cal a BP), the climate in this period became dry with lower lake level and strong hydrodynamic conditions.Sixth stage (4000～0 cal a BP), the climate mainly tended to slightly warm and humid with higher Lake level and weak hydrodynamic conditions.The proeess of climatic and environmental evolution since 18 cal ka BP age in Wusulangzi Lake is consistent of former study results of the relative areas.Some global climate events,such as Allenad warm stage and Younger Dryas event,are recorded in the sediment in Wusulangzi Lake. But with regard to the beginning and ending time of all the stages and the climate characters in different stage,there are some diffierence in study area with the relative areas,which is own the the dating error or the sensitivity of different climate proxies.Maybe it is the special climate character Wusulangzi Lake,which are looking forward to the further study in the future. Solar activities may be the dominant force that drove the climate changes in Wusulangzi Lake area since 18ka years ago.