【摘要】 通过对吕梁山前(西)山西保德剖面和柳林剖面的野外考察,结合前人研究成果,研究了新近纪地层的组成及空间分布。新近纪地层自下而上可以分为三段:下段为水成砂砾石层,上段为风尘堆积的红粘土,中部则为二者的过渡带。柳林剖面的详细研究揭示了水成堆积物与红粘土的细部特征:粗粒的砾岩和砂岩常切穿红粘土层,而粒度与红粘土相近的泥岩则常与红粘土平行产出。野外调查结合区域资料分析表明新近系各组成成分空间分布具有明显的规律性:靠近吕梁山(保德剖面)下部水成堆积物粒度较粗且厚度较大,红粘土厚度相对较薄;背离吕梁山下部水成堆积物逐渐变细且厚度减薄(柳林剖面、府谷剖面)直至尖灭(佳县剖面),与之伴生的是红粘土厚度逐渐增大;中间过渡带中水成堆积物与红粘土的比例与此相似,即区域上吕梁山前的水成堆积物呈楔状"侵入"于红粘土的中下部。红粘土与水成堆积物的关系的确立为更好的理解红粘土的成因、吕梁山的新生代隆升历史及恢复新近纪晚期的古气候演变具有重要意义。更多还原

【Abstract】 On the basis of field geological investigation in Liulin and Baode in Shanxi province,together with other researcher’s results,the spatial distribution and material composition of Neogene strata were studied.Neogene strata can be divided into three parts in vertical:The bottom is mainly composed of aqueous deposits,the top is aeolian red clay;the middle part is transitional layer.Further research on Liulin Section reveals the detail characteristics of red clay and aqueous deposits:coarse grain sandstone and gravel cut through red clay,but the fine mudstone parallel to red clay.The character of spatial distribution and material composition of Neogene strata are as follows:the size and thickness of queous deposits is large and thickness of red clay is small near to Luliang Mountain(such as Baode section).The size and thickness of fluvial deposits decrease form Luliang Mountains to Ordos Basin,on the contrary,thickness of red clay increase.Proportional change of red clay and aqueous accumulation transitional layer is the same,which means aqueous deposits wedge red clay base like an asymmetric wedge.The relation between red clay and aqueous accumulation can help us understand the cause of red clay and recover the uplift history of Luliang mountain and paleoclimate evolution.更多还原