【摘要】 <正> 几乎所有关于泥河湾层的著述中,皆或多或少地涉及泥河湾层形成的古地理环境问题.早在二十年代,Barbour,G.B.和Licent,E.等人,即根据泥河湾动物群的性质,认为泥河湾期相当温暖湿润,同时也指出该层上部的蒸发岩,标志着后期气候变干的趋势.六十年代以来,北京大学等单位,对湖盆演变及其与新构造运动关系等问题,做了较为详细的研究.近年来微体古生物的研究,提供了大量的古气候信息.周昆叔研究了红崖南沟剖面下部孢粉谱,认为这里记录了一个“冷期”.刘金陵(1980)研究了虎头梁剖面下部孢粉谱,认为它代表一种“凉——北方型”气候.任振纪研究了蔚县142钻孔孢粉组合,认为泥河湾层记录了三个“冷期”.汪品先等(1975)在东窑子头发现的有孔虫更多还原

【Abstract】 This paper deals wtth some paleogeographic conditions in the time of the ac-cumulation of Nihewan series.Main conclusions are as follows:1) The Nihewan series recorded four cold periods, the first three of which appeared during the depositional time and the last was after it. All the four periods occurred in the middle of the early Pleistocene(Q12), the early and the late of the middle Pleistocene (Q21 & Q21) and the late of the late Pleistocene (Q33) res-pectively. They are probably the equivalents to the glacial epochs of Gz, Mind-el, Ress and wurm in Europe.2) The contrasted geomorphological development between the basin and the mountain sector was initiated by the neotectonic movement which started in the middle-late Pliocene, and the ancient Nihewan Lake was shaped at the beginning of the early Pleistocene, through a narrow form from Q11 to Q12, to a spreading form during Q13 and Q2, and vanished at the late Pleistocene(Q3).3) The neotectonic movement was the main cause of the lake’s evolution, al-though climatic changes were the other reasons.更多还原