辽南地区末次冰期以来的环境变化  

The Change of The Climate and Environment Since the Last Glacial Cycle in The South of Liaoning Province

作　　者：李大鹏[1] 刘蓓蓓[1] 

机构地区：[1]辽宁师范大学城市与环境学院,辽宁大连116029

出　　处：《科技信息》2012年第23期40-43,共4页Science & Technology Information

摘　　要：本文通过对大连七顶山黄土剖面的光释光(OSL)年代、磁化率、地球化学元素、粒度特征等数据,综合分析辽南地区末次冰期以来的环境变化过程,研究结果显示:相当于黄土高原马兰黄土的堆积形成时代为距今125ka。在末次冰期早期(MIS4-5d),86-113ka,沉积物质量磁化率介于6.97-24.14×10-8m3kg-1之间,平均值为14.699×10-8m3kg-1;颗粒粒径较细(3.89-5.22准);硅铝率平均值6.756;风化淋溶系数0.4-0.73之间;退碱系数均值0.333;镁铝比均值22.901。与末次冰期晚期相比,质量磁化率值较高,化学元素各项指标值较低,明了该阶段辽南整体气候环境较为干冷,但并未达到末次冰期晚期程度。而在末次冰盛期时(22-31ka,MIS2),磁化率平均值为6.974×10-8m3kg-1,明显低于末次冰期早期,粒度均值处于3.47准-4.77准之间,主要以颗粒较粗的细砂、粗粉砂为主,粒度明显变粗,硅铝率平均为6.998;风化淋溶系数均值为0.829,退碱系数值0.66,镁铝比值均值28.725,各参数比较一致地表明该阶段研究区整体处于干冷的气候环境之下,堆积作用较活跃。而在末次冰期中期(MIS3)时,OSL年代31-86ka,该区气候条件以温暖湿润为主,黄土遭到侵蚀。According to the sample from the typical loess profile in Qiding shan, lots of chronology means were used to comprehensive analysis the change of the climate and environment in the south of Liaoning province since the last glacial cycle in this paper, such as the Optical stimulated luminescence dating（OSL）, magnetic susceptibility, global chemistry element, granularity characteristic, at the same time, compared with the other sites of the loess sedimentary environment feature in the coastal areas in southeast China. It infers that with the age of 125kaB.p., in the south of Liaoning province, based on direct dating of the loess deposits using osl , the timing of these sediments was dated at 22-31 ka B.p. and 28-42ka B.p., corresponding to marine isotope stage （MIS）4-5d and 2 respectively, the average value of the mass susceptibility is 14.699×10^-8m^3kg^-1 and 6.974×10^-8m^3kg^-1,the average value of the ratio of silicate to aluminlum is 6.756 and 6.998. All these index suggest that at the beginning part of the last glacial cycle the climate was both dry and cold, and in the late part it became drier and colder. At the middle part （MIS3）, the osl timing result was 31-86 ka B.p., especially during 28-42ka, because of wave erosion in the south of Liaoning province ,the loess suffered from erosion, so we infer the climatic conditions was not only warm but also humid.

关 键 词：辽南 马兰黄土 末次冰期 

分 类 号：P532[天文地球—古生物学与地层学]