Abstract. Albian to Turonian carbonate deposits at three different locations of the
Lower Saxony Cretaceous and thereby of the European mid-Cretaceous epeiric
shelf sea were investigated for their fossil agglutinated foraminiferal
fauna. In this study, 71 samples from two quarries and three drill cores
were treated with formic acid, which enabled the study of agglutinated
foraminiferal assemblages even in highly lithified limestones. In total, 114
species were determined and classified as belonging to nine morphogroups. In
general, four agglutinated foraminiferal assemblages are distinguished: (1) an uppermost Albian–lowermost Cenomanian assemblage from the Wunstorf drill
cores, with the dominant taxa
Bathysiphon spp., Nothia spp., Psammosphaera fusca, Reophax subfusiformis, Bulbobaculites problematicus, Tritaxia tricarinata, Flourensina intermedia, Vialovella frankei, Arenobulimina truncata, and Voloshinoides advenus; (2) a Cenomanian
assemblage from the Baddeckenstedt quarry and Wunstorf drill cores, with
Ammolagena clavata, Tritaxia tricarinata, Vialovella frankei, Arenobulimina truncata, and Voloshinoides advenus; (3) an assemblage related to the Cenomanian–Turonian Boundary Event in
Wunstorf and Söhlde dominated by Bulbobaculites problematicus; and (4) a Turonian assemblage in the
Wunstorf and Söhlde sections with high numbers of Ammolagena contorta, Repmanina charoides, Bulbobaculites problematicus, Gerochammina stanislawi, and
Spiroplectammina navarroana. The latest Albian–earliest Cenomanian assemblage consists of tubular,
globular, and elongate foraminiferal morphogroups which are typical for the
low- to mid-latitude slope biofacies. All other assemblages are composed of
elongate foraminiferal morphogroups with additionally globular forms in the
proximal settings of Baddeckenstedt and Söhlde or flattened planispiral
and streptospiral forms in more distal settings of Wunstorf. For these
assemblages, a new agglutinated foraminiferal biofacies named “mid-latitude
shelf biofacies” is proposed herein. Changes in the relative abundance of
different morphogroups can often be referred to single features of
depositional sequences. Furthermore, classical macro-bioevents, which are
often depositional-related, of the Lower Saxony Cretaceous seem to have a
micro-bioevent or acme equivalent of the agglutinated foraminiferal fauna.
Albian to Turonian agglutinated foraminiferal assemblages of the Lower Saxony Cretaceous sub-basins – implications for sequence stratigraphy and paleoenvironmental interpretation
