Palaeoecology, facies and stratigraphy of shallow marine macrofauna from the Upper Oligocene (Palaeogene) of the southern Pre-North Sea Basin of Astrup (NW Germany)

Abstract

AbstractThe 22 meter thick marine carbonate Upper Oligocene series of Astrup (NW Germany) is correlated with the Chattian type section of Doberg. It indicates a more constrained palaeogeographical and biostratigraphical position ranging from the biozones of Chlamys (C.) decussata (upper Chattian A) to Chlamys (C.) semistriatus (lower Chattian C). The macrofauna can be subdivided into three main benthic communities: A. the „coarse gravel spondylid beach fauna“ of the shore zone with „pebble beach facies“ dominated by sessile brachiopods, large balanids, spondylids, oysters or small regular echinoids. Borings are common in pebbles; B. the „glauconite fine gravel brachiopod-bryozoan littoral fauna“ of the shallow subtidal zone where a terebratulid/lithothamnid dominated fauna/flora is present. The rhodophyceans were most possibly anker stones and substrates for cirripeds and serpulids; C. the „glauconite carbonate sand phytal fauna“ of the shallow subtidal zone with a rich benthic mollusc dominated fauna. Indirect evidence for seagrass and macroalgae occurs on the attachment negatives of balanids and oysters, and also on Cibicides foraminifera or bryozoans like Cellepora. The facies types along the Wiehengebirge Island and Teutoburger Wald Peninsula coasts of the southern Pre-North Sea Basin differ with respect to their benthic communities to that of the siliciclastic Leipziger and the Rhenish Bay facies.