摘要
通过对辽南滨海地区第四纪黄土沉积物的磁化率测量和分析,发现该区马兰黄土的磁化率值不高,反映了该区晚更新世受末次冰期影响,气候条件干冷,黄土粉尘沉积速率快,成壤作用微弱;时间更早的离石黄土磁化率值偏高,反映其成土环境较为温暖潮湿,黄土粉尘堆积速率慢,成壤作用好。磁化率曲线的波动变化反映了古气候发生多次旋回变化;黄土-古土壤序列很好的指示了干冷、暖湿气候的交替,也对应了冬季风、夏季风的交替变化。根据磁化率值对古气温和古降水量的回归计算得到古气温应介于5.85℃～13.0℃(+1.5℃),古降水量介于403.22mm～735mm,其标准都低于当今水平。反演辽南滨海地区中、晚更新世时期的黄土沉积环境是比较干冷的,并且经历了多次的小规模的干冷、暖湿交替变化。
Through measuring and analysing the magnetic susceptibility of seashore in quaternary loess south Liaonan,it＇s revealed that the magnetic susceptibility datas of Malan loess is lower.In the late pleistocene epoch,the climate here was dry and cold,and the sedimentation rate was relatively higher,which affected by the last Glaciation,so it＇s weak in pedogenesis.When come to Lishi loess which formated in the earlier period,the datas reflect a moist climate with lower sedimentation rate and strong pedogenesis.The fluctuation of loess magnetic susceptibility curve reflected that there had been several paleoclimatic cyclical transformations,and the loess-paleosol sequences indicated that there clearly had been a dry-cold to warm-wet cyclical transformation,meanwhile,corresponding to the winter-summer monsoon cyclical transforming.According to regression equation of the temperature and precipitation based on the magnetic susceptibility datas,the Paleo temperature varies in a range of 5.85 ℃ to 13.0 ℃（＋1.5 ℃） and the Paleo precipitation varies in a range of 403.22 mm to 735 mm,which is lower than nowadays level.It＇s inverting that during the Medio Pleistocene,the late pleistocene epochthe,the paleoclimatic of loess sedimentating in south Liaonan is relatively dry and cold,and undergoing multiple miniature dry-cold to warm-wet alternate transformation.
出处
《沈阳师范大学学报（自然科学版）》
CAS
2012年第4期552-557,共6页
Journal of Shenyang Normal University:Natural Science Edition
基金
国家自然科学基金资助项目(40971010)
关键词
黄土
磁化率
古气候
loess
magnetic susceptibility
paleoenvironment
