Abstract We present a sedimentological analysis of the Wielkopolska Member, the upper unit of the Poznan Formation which formed in a fluvial environment within a tectonic graben during the middle Miocene to early Pliocene in Poland. Large excavations in a lignite opencast mine have enabled our study of palaeochannel infills, in which sandy to silty-clayey ribbons are scattered within overbank clays. Channel sedimentation was controlled mainly by silty-clayey suspension settling and counter point bar accretion, with sinuous dunes and cut-and-fill of scours as secondary depositional agents. Lithofacies frequency indicates that the channel facies derived from both fine-grained suspension and bedload. The river was low energy, with the power of flood flows calculated in the range of 2.5 to 21 W m−2. Washload concentration was high, as demonstrated by thick silty-clayey packages within palaeochannels, the presence of climbing dunes and the relatively low number of ripple-derived beds. Alluvial channels were deep and narrow (3–4 m and 70–90 m for main channels; 2–3 m and

中文翻译：

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沉积记录中的吻合到蜿蜒的过渡河：以波兰中部新近纪为例

摘要 我们介绍了 Wielkopolska 段的沉积学分析，该段是波兹南组的上部单元，在波兰中中新世至上新世早期构造地堑内的河流环境中形成。褐煤露天矿的大型挖掘使我们能够研究古河道填充物，其中沙质至粉质粘土带散布在堤岸粘土中。河道沉积主要受粉质粘土悬浮沉降和反点坝体控制，以蜿蜒的沙丘和冲刷冲刷为次生沉积作用。岩相频率表明河道相同时来自细粒悬浮和床荷。这条河是低能量的，计算出的洪水功率在 2.5 到 21 W m-2 范围内。洗涤负荷浓度高，正如古河道内厚厚的粉质粘土包裹所证明的那样，存在攀爬沙丘和相对较少的波纹衍生床。冲积河道深而窄（主河道为 3-4 m 和 70-90 m；2-3 m 和