晚冰期以来毛乌素沙漠环境特征的湖沼相沉积记录  

The Lake Swamp Sediment Records on the Environmental Characteristics of Mu Us Desert since the Late Glacial Epoch

作　　者：苏志珠[1,2,3] 董光荣[1,2,3] 李小强 陈惠忠[1,2,3] 

机构地区：[1]中国科学院兰州沙漠研究所 [2]中国科学院西安黄土与第四纪地质实验室 [3]山西大学黄土高原研究所

出　　处：《中国沙漠》1999年第2期104-109,共6页Journal of Desert Research

基　　金：中国科学院重大项目;国家自然科学基金

摘　　要：毛乌素沙漠南缘靖边海则滩湖沼相沉积剖面，真实地记录了晚冰期以来东亚季风气候和沙漠演化历史。在地层沉积相划分和测年基础上，据地球化学元素和孢粉等气候指标分析表明，该区古气候变迁序列为：１２ｋａＢＰ前干燥寒冷；１２～１０ｋａＢＰ气候转暖湿；１０～８．５ｋａＢＰ以温湿为主，在１０～９．５ｋａＢＰ出现ＹｏｕｎｇｅｒＤｒｙａｓ冷干事件；８．５～３．０ｋａＢＰ温暖湿润；３．０ｋａＢＰ后气候趋于半干旱与现代气候较接近。这种气候演化规律是受地球轨道因素影响。The d esert loess transitional zone located between the northern part of loess platea u and the southern fringe of Mu Us Desert is very sensitive to the climatic changes. There has received great attention. In this paper, Haizetan profile o f Jinbian County (37°42′N,108°48′E) situated in the southern edge of Mu Us Desert, has developed a thick lake swamp sediments, which has completely docume nted the history of East Asia monsoon and desert evolution since the late glac ial epoch. The major climatic variations have been recorded and analyzed based o n the sedimental facies, stratigraphic data, geo chemistry, pollen records from lake swamp deposit sequences. Some results are concluded: (1) The climate bef ore 12 ka BP was colder and drier than that in Holocene; Sediments with a thick eolian sand layer indicated intensified winter monsoon and strong wind sand activities. (2) During the period from 12 to 10 ka BP, climatic indicator analysis reflected higher content of Fe 2O 3, Al 2O 3,Co,Ni and lower content of Na 2O,K 2O,Sr,Ba, and high pollen concentration, which suggested that climatic conditions had started to ameliora te and became relatively warm and wet. (3) During the period of 10￣8 5 ka B P, the general climate was warmer and wetter, which was resulted from enhanced s ummer monsoon activity due to the increased summertime solar radiation in Northe rn Hemisphere. During the period the summer monsoon dominated and precipitation, pollen volume increased. Around about 9 ka BP, the pollen volume reached its peak, rainfall was abundant. However, the lowest pollen content between 10 and 9 5 a BP indicated that the climate changed to dry cold dramatically and deposi ted eolian sand layer. This stage matched the Younger Dryas sub period of North Atl antic Period in Europe. (4) The period between 8 5 and 3 0 ka BP correlated with Megathermal Phas e of Holocene. The climate became warmer and wetter resulted from intensified s ummer monsoon activity. Many researches indicate that during

关 键 词：晚冰期 毛乌素沙漠 气候变化 环境特征 沉积记录 

分 类 号：P532[天文地球—古生物学与地层学] P512.3[天文地球—地质学]