【摘要】 对浑善达克沙地7个晚更新世末期风成砂—全新世黑色砂质土壤序列剖面进行了光释光年代测试,并对26个野外风成剖面进行了考察及粒度、磁化率测量。通过对黑色砂质土壤层之下砂层粒度、磁化率指标分析,砂层OSL测年,确定了末次冰期晚期浑善达克沙地活动砂丘分布范围。目前浑善迭克沙地为砂质草原,主要为固定砂丘,面积约52000 km~2,流砂面积约不到20%。末次冰期由于沙地活化,流砂面积达到约200000 km~2,面积扩大了近20倍。沙漠北部越过锡林浩特草原和西乌珠穆沁沙地连片,南部到达张北地区,东部抵大兴安岭西缘,部分区域与科尔沁沙地连接,西部接戈壁、基岩剥蚀区。浑善达克沙地内部河流与湖泊发育,在冰期干冷环境下,河流与湖泊水位下降,河流与湖泊砂暴露并遭受风蚀改造,为流砂扩张提供物源。更多还原

【Abstract】 OSL study on sand and fossil soil from Otindag sandy land in eastern China was reported in this paper.Aeolian dune sequences responded to the climate change by virtue of alternations of aeolian sand and sandy soil,which corresponded to arid and humid conditions,respectively.In this desert,there is a set of contrastive deposits made up of loose sand and overlying dark sandy soil just below land surface.Optical dating using SAR technique with quartz was applied to the deposits.The results indicate that the developed soil and underlying deep aeolian sand responsed to the Holocene optimum(HO) and the last late glacial,respectively.The rough extension of last late glacial sand was revealed by studying about 26 profiles.Combined with studies of grain-size,magnetic susceptibility and sediment color,the environment of the desert is reconstructed.The results suggest that the mobile sand was stabilized and contracted gradually when approaching Holocene.It was completely covered by vegetation in H.O.With rivers and lakes inside Otindag Desert developed the water level of them has lowered in the dry and cold environment of the glacial stage and the rivers and lakes subjected to wind erosion and reform has provided the enlargement of drift sand with material resources.更多还原