末次冰期以来辽东半岛风沙沉积的粒度端元特征与古气候演变研究  

THE END-MEMBER CHARACTERISTICS OF THE GRAIN SIZE OF THE AEOLIAN SAND DEPOSITS IN THE LIAODONG PENINSULA SINCE THE LAST GLACIAL PERIOD AND THE STUDY ON PALEOCLIMATE EVOLUTION

作　　者：王思齐[1] 魏东岚[1] 张威[1] WANG Siqi;WEI Donglan;ZHANG Wei(School of Geographical Sciences,Liaoning Normal University,Dalian 116029,Liaoning)

机构地区：[1]辽宁师范大学地理科学学院,辽宁大连116029

出　　处：《第四纪研究》2022年第2期338-349,共12页Quaternary Sciences

基　　金：辽宁省自然科学基金项目(批准号:2019-ZD-0475);辽宁省自然科学基金项目(批准号:20180550389)共同资助。

摘　　要：辽东半岛风沙沉积位于东亚季风区边缘和海陆交界地带,对研究东亚季风演化、海平面升降变化、古气候环境变迁等具有重要意义。采用参数化端元分析模型对辽东半岛整体厚320 cm的风沙沉积剖面的粒度数据进行分析,提取出反映沉积动力特征的3个端元组分,结果表明:1)EM1由细粉砂和极细砂组成,是受冬季风影响的敏感粒级,指示冬季风强度变化,EM2与EM3由粒径较粗的细砂和中砂组成,在低空地方风系作用下以尘暴形式对近地表粗颗粒沉积物进行搬运堆积;2)OSL测年结果显示剖面自末次冰期开始堆积,期间经历了冷暖旋回的气候变化,并发育相应的沉积地层;3)结合OSL测年结果,各端元含量、磁化率和中值粒径与深海氧同位素曲线变化趋势基本一致,说明辽东半岛风沙沉积揭示的沉积环境演变与全球环境变化密切相关,虽然存在一定的内部差异,但在反演古气候变迁方面仍具有很好的优越性,是研究渤海沿岸古环境特征的良好信息载体。The aeolian sand deposits on the Liaodong Peninsula are located at the edge of the East Asian monsoon region and the land sea junction,which is of great significance to the study of the evolution of the East Asian monsoon,sea level fluctuation,and paleoclimatic environment changes.In this paper,we obtain an aeolian sand depositional profile in the Liaodong Peninsula,named JC(39°35’52″N,121°25’45″E;32 m a.s.l.;320 cm in thickness),and collect samples at 5 cm intervals.The lithological characteristics of the stratum are:the upper layer 25 cm is topsoil.25~55 cm is mostly fine silt sand,the weakly developed sandy paleosol layer is dominated by very fine sand,and the color is brownish yellow;55~320 cm is dominated by fine sand and medium sand,yellow aeolian sand deposition.Using optical luminescence dating measurements combined with linear interpolation and extrapolation,the age range of the profile is calculated to be around 6~67 ka B.P.The parameterized end member analysis model is used to analyze the grain size data of the 320 cm thick aeolian sand depositional section in the Liaodong Peninsula,which was developed in the Late Pleistocene,and three endmember components reflecting the sedimentary dynamic characteristics were extracted.The results show that:(1)EM1 is composed of fine silt and very fine sand,which is the sensitive grain size affected by the winter monsoon,indicating the intensity change of the winter monsoon.EM2 and EM3 are composed of coarser fine sand and medium sand.Under the action of low altitude local wind system,dust storms affect near surface coarse grained sediments.Carry out transportation and stacking.(2)The OSL dating results show that the profile began to accumulate since the last glacial period,during which it experienced climate changes of cold and warm cycles and developed corresponding sedimentary strata.(3)Combined with the OSL results,the content of each end member,magnetic susceptibility and median size are basically consistent with the change trend of the deep-sea oxygen

关 键 词：风沙沉积 端元分析 OSL测年 古气候演变 

分 类 号：P532[天文地球—古生物学与地层学] P534.63[天文地球—地质学]