晋西北地区末次盛冰期古风成砂的发现及环境演化  

THE DISCOVERY OF PALAEO EOLIAN SAND FORMED IN THE LAST GLACIAL MAXIMUM AND ENVIRONMENTAL EVOLUTION IN THE NORTHWEST OF SHANXI

作　　者：苏志珠[1,2] 马义娟[1,2] 

机构地区：[1]山西大学黄土高原研究所 [2]山西大学师范学院地理系

出　　处：《中国沙漠》1997年第4期389-394,共6页Journal of Desert Research

摘　　要：野外调查中在晋西北地区首次发现了马兰黄土中的古风成砂沉积，其机械组成主要是极细砂和细砂，而且具有明显的风成交错层理等特征。结合年代资料和孢粉分析，认为古风成砂形成于２７０００～１００００ａＢ．Ｐ．间的末次冰期盛冰期，当时晋西北地区是干旱荒漠－干草原景观，气候寒冷干燥，风的地质作用成为控制该区环境变化的主要动力因素，沙漠化土地迅速扩展或沙漠大范围地南侵。In the Northwest of Shanxi Province ,we have firstly found some ancient aeolian sand deposit in Malan loess layer. The ancient aeolian sand deposit is not only composed mainly of finesand and very finesand but also with very clear cross bedded structure. Therefore, it is typical aeolian sand formed by wind action. The age dated by fossil ice wedges showed that the ancient aeolian sands were formed between 27￣10 ka B.P.. The analysis of sporo pollen indicated that the climate at that time was rather cold dry and windy and the bioclimatic zones shifted from the desert steppe to dry steppe in this area.

关 键 词：古风成砂 末次盛冰期 环境演化 风砂流 

分 类 号：P532[天文地球—古生物学与地层学] P425.55[天文地球—地质学]