【摘要】 <正> 泥河湾位于河北省阳原县东部,是研究我国第四纪地层、古生物、古人类、新构造运动及古地理等学科的著名地区.关于泥河湾层的划分对比问题,是多学科研究工作中的基础性课题,一直受到学术界的广泛重视.笔者近几年来在泥河湾地区,从事新生代古地理研究工作,根据我们对一些较新资料的研究和分析,就地层划分对比问题,提出一点尝试性看法,敬请批评指正.更多还原

【Abstract】 The well-known Nihewan Formation is a suite of river-lacustrine fcies deposits developed in a series of intermontane fault basins of songganhe drainage area, and it has been regarded as the lower Pleistocene index bed of North China over a long period of time. But in the recent years, a great many of actual materials have proved that the Nihewan Formation is time-transgressive, therefor the division of this formation is obviously necessary, and many schemes for the division and correlation were proposed since then. these schemes, however, are divergent considerble, no decision can be reached.Based on the new materials of lithofacies, maro- and microfossils, and pa-lomagnetic dating, started from environmental analysis of every section of the profils with the principle of synthsis, several typical section of Nihewan Formation in the eastern part of Yangyuan Basin were divided and correlated.We have discovered that the developments and autcropigs of section in the different neotectonic units were different, thus these sections were not equated each other. In fact, the upper middle part of the Pumping Station section is corres-ponding to the lower part of the Haojiatai section, the upper part of the Hao- jiatai section is corresponding to lower part of the Hutouliang section. Connected all of them together, the geologie column of Nihewan Formation will be completed.The lower Pleistocene can be divided into three members. The lower member only outcropped nearby the Pumping Station, it represents warm and humid en-veronment. The middle member outcropped in the upper middle part of the Pumping Station section and the lower part of the Haojiatai section, it represents cool and arid climate, and the heteropic flood deposits were rather developed, fossils contained were rather abundant, the Nihewan Fauna produced from this member. The upper member was seen in the middle part of the Haojiatai section, shallow lacustrine and delta facies deposits were develped, the climate turned a little bit humid. The middle Pleistocene was seen in the top part of the Haojiatai section and the iower part of the Hutouliong saction, the distribution of this series was the most widespread and the area of the ancient lake was the largest. The climates of the early and the late middle Pleistocene were humid, but the climate in the middle of the middle Pleistocene was arid, and the heteropic Lishi loess and flood sediments were deposited. The upper Pleistocene was only seen in the upper part of the Hutouliong section, its distribution was limited and offlapped on the middle Pleistocene, the area of the lake was very small, the climate was arid gradually. From distribution of the strata it can be suggested that the ancient lake contracted from the Huliuhe graben in the east toward the depresion center of the Songganhe graben, till it was vanished.To gain a ciear idea of the division and correlation of the Nihewan Formation will be of great significance for further investigating the development of ancint lake and the evolution of paleoenvironment.(D. H.)更多还原