Distribution and significance of foraminiferal biofacies on an aphotic Danian bryozoan mound, Karlstrup, Denmark

In this study, the distribution of benthic foraminifers across a Danian bryozoan mound in Karlstrup quarry, Denmark, is analysed in 22 samples using multivariate analysis. Three foraminiferal biofacies are established, each representing a distinct part of the mound. The Anomalinoides-Cibicides- Osangularia Biofacies is characteristic of the relatively pure carbonate sediments on the crest and flanks of the bryozoan mound. The Patellina Biofacies occurs at the mound flanks and is particularly common in marly sediments. The Spirillina Biofacies characterises the crest of the bryozoan mound, in both marly and pure carbonate sediments. Variations in the plankton/benthos ratio indicate that the benthic foraminifers prefer the marly sediments to pure limestone and mound flanks relative to the mound top. It is likely that the benthic foraminifers avoided the more powerful currents at the mound crest. The common occurrence of spirillinids on the mound top may represent the remnant of a rich, siliceous sponge community.