Biogenic and mineral composition and foraminiferal stratigraphy of sediment cores obtained in northern Germany

The Ratekau boring ended in clays of the so-called Asterigerina-Zone; these clays have shallow-water features in the uppermost samples. The clays are overlain by deep-water clays with pteropods; this formation is split into two parts by a shallow-water deposit. The fossiliferous series ends upward in sandy deposits with shallow-water fossils. The question is raised whether the two deep-water deposits might correspond to the Lower Doberg Beds (Eochattian) and the Upper Doberg Beds (Neochattian) at the Doberg hill, closer to the rim of the basin. All fossiliferous samples from this boring are thought to be of Late Oligocene age; the boundary towards the Middle Oligocene, however, could not be ascertained. The Vaale boring ended in rather typical Septaria clay of the Middle Oligocene. This clay is capped by some metres of unfossiliferous glauconite clays, which in turn are overlain by silts and silty clays with planktonic fossils identical to those found at Dingden locality. These deposits are tentatively dated as Early Miocene. The next higher series of samples consists of sands and clays deposited in shallower waters. They contain a rich fauna of benthic molluscs, which, according to the current notion in stratigraphy, would have a Reinbek Age. In addition, they contain a set of planktonic fossils which differs from the 'Lower Miocene' assemblages. These sands and clays are overlain by a thick series of marine sands very poor in fossils. Finally, four metres of clay with foraminifera, having Younger Miocene affinities, form the top of the fossiliferous sequence. The borings at Wulksfelde and Langenhorn were not far apart and their sediments are easily correlated. Both wells start below in continental 'Lignite Sands' and contain overlying shallow water sands and clays. These yielded Hemmoor benthic mollusca, supposed to indicate Lower Miocene in the relevant literature; however, we encountered their planktonic foraminifera in the uppermost Miocene as well. The same planktonic species were found in all samples of both borings. These deposits under discussion furthermore contain a particular pteropod species. They are overlain by a thick series of gypsiferous clays, with scarce fossils. The uppermost fossiliferous clays (probably Langenfelde Age) contain another pteropod species, not met with in other samples. […]

拉特考钻孔（Ratekau boring）终止于所谓的星轮虫带（Asterigerina-Zone）黏土中；其最上部样品中的黏土具有浅水沉积特征。该黏土之上为含翼足类的深水黏土；这套地层被一套浅水沉积分割为两部分。含化石层序向上终止于含浅水化石的砂质沉积中。目前提出的问题是，这两套深水沉积是否对应于更靠近盆地边缘的多贝格山（Doberg hill）的下多贝格层（早恰特期，Eochattian）和上多贝格层（新恰特期，Neochattian）。该钻孔的所有含化石样品均被认为属于晚渐新世；但与中渐新世的界限无法确定。

瓦勒钻孔（Vaale boring）终止于中渐新世典型的龟裂纹黏土（Septaria clay）中。该黏土之上覆盖着数米厚的无化石海绿石黏土，其上方又为粉砂和粉砂质黏土，含与丁登地区（Dingden locality）发现的相同的浮游生物化石。这些沉积暂定为早中新世。再往上的样品层序由浅水沉积的砂和黏土组成，含丰富的底栖软体动物群；根据当前地层学观点，这些沉积属于赖因贝克期（Reinbek Age）。此外，其含有的浮游生物化石组合与“早中新世”组合不同。这些砂和黏土之上覆盖着厚层的海相砂，化石含量极少。最后，含有孔虫的四米厚黏土构成含化石层序的顶部，其具有晚中新世亲缘性。

武尔克费尔德（Wulksfelde）和朗根霍恩（Langenhorn）钻孔相距不远，其沉积物易于对比。两口井的下部均为陆相“褐煤砂”（Lignite Sands），上部为浅水砂和黏土。这些沉积产出黑莫尔底栖软体动物（Hemmoor benthic mollusca），相关文献认为其指示早中新世；但我们在最上部的中新世也发现了其浮游有孔虫。两口钻孔的所有样品中均发现了相同的浮游生物种；此外，所讨论的沉积中还含有一种特殊的翼足类。其上方覆盖着厚层的含石膏黏土，化石稀少。最上部的含化石黏土（可能属于朗根费尔德期，Langenfelde Age）含有另一种翼足类，未在其他样品中发现。[…]