Ammonite biostratigraphy and correlation of Middle/Late Albian drilling cores in the Hannover area (northern Germany)

Abstract

The ammonite biostratigraphy of the Middle/Late Albian boundary interval in northern Germany has been significantly improved in the past few years by the Hannover-Lahe and Hannover-Kirchrode borehole sections. Both sections show are monotonous claystone successions deposited in a deep sub-basin of the Lower Saxony Basin. Here ammonite data of the Hannover-Lahe core are revised and re-evaluated, placing the section into the latest Middle/early Late Albian and allowing a correlation with the neighbouring Hannover-Kirchrode succession as well as the standard section for ammonite biostratigraphy on the European shelf – the Folkestone section in the UK. It demonstrates that sedimentation rates in this sub-basin of the Lower Saxony Basin were extremely high during the earliest Late Albian Dipoloceras cristatum Zone and the Hysteroceras orbignyi Subzone of the Hysteroceras varicosum Zone compared to all other well-dated sections available. The succession in the H. binum/choffati Subzones, indicates a short period of distinctly reduced sediment accumulation, before the greatly increased sedimentation rate during the Callihoplites auritus Subzone of the Mortoniceras inflatum Zone.