The benthic macrofauna from the Lower Maastrichtian chalk of Kronsmoor (northern Germany, Saturn quarry): taxonomic outline and palaeoecologic implications

Abstract

The benthic macroinvertebrates of the Lower Maastrichtian chalk of Saturn quarry at Kronsmoor (northern Germany) have been studied taxonomically based on more than 1,000 specimens. Two successive benthic macrofossil assemblages were recognised: the lower interval in the upper part of the Kronsmoor Formation (Belemnella obtusaZone) is characterized by low abundances of macroinvertebrates while the upper interval in the uppermost Kronsmoor and lowermost Hemmoor formations (lower to middleBelemnella sumensisZone) shows a high macroinvertebrate abundance (eight times more than in theB. obtusaZone) and a conspicuous dominance of brachiopods. The palaeoecological analysis of these two assemblages indicates the presence of eight different guilds, of which epifaunal suspension feeders (fixo-sessile and libero-sessile guilds), comprising approximately half of the trophic nucleus of the lower interval, increased to a dominant 86% in the upper interval, including a considerable proportion of rhynchonelliform brachiopods. It is tempting to relate this shift from the lower to the upper interval to an increase in nutrient supply and/or a shallowing of the depositional environment but further data including geochemical proxies are needed to fully understand the macrofossil distribution patterns in the Lower Maastrichtian of Kronsmoor.

The early Cenomanian crippsi Event at Lüneburg (Germany): palaeontological and stratigraphical significance of a widespread Late Cretaceous bioevent

“…Palaega carteri or Cardiaster granulosus). However, such a predominance of epibenthic taxa in macrobenthic offshore assemblages from Upper Cretaceous chalks has also been demonstrated by Engelke et al (2016), without any palaeoecological (Engelke et al 2017) or geochemical (Engelke et al 2018) evidence for oxygen restriction.…”

The brachiopod assemblage from the Maastrichtian white chalk at Chełm, eastern Poland: stratigraphical and palaeoecological implications

“…Except for burrowing Lingula, all brachiopods from the European white chalk in general, and from the Chełm succession in particular, represent a guild of fixo-and libero-sessile epifaunal suspension feeders as distinguished by Engelke et al, (2016Engelke et al, ( , 2017 in their study of early Maastrichtian macrobenthos at Kroonsmoor, northwest Germany. In view of the ecological requirements of this group, the development of the Late Cretaceous brachiopod communities in the Boreal Chalk Sea of Europe must have been controlled largely by two interrelated environmental factors: 1) input of food and nutrients, and 2) availability of minute skeletal substrates which would have been suitable for brachiopod settlement (Surlyk, 1972;Hansen & Surlyk, 2014;Engelke et al, 2016Engelke et al, , 2017. Both factors were, in turn, indirectly influenced by the depth of the Boreal Chalk Sea and its variations (e.g., Hansen & Surlyk, 2014).…”

“…The Chełm chalk was deposited in an epicontinental setting, in the eastern part of the Boreal Chalk Sea of Europe (e.g., Surlyk et al, 2003; Engelke et al, 2016, 2017). The Chełm chalk matches the characteristics of the ‘benthos-poor’ variety of white chalk in the Boreal Chalk Sea facies model, representing the deepest epicontinental chalk facies, deposited below the photic zone and storm wave base (Surlyk et al, 2003, Fig.…”

Colony growth strategies, dormancy and repair in some Late Cretaceous encrusting bryozoans: insights into the ecology of the Chalk seabed

“…These shallow infaunal deposit feeding holasteroids (e.g. Engelke et al 2016) formed 'benthic islands' on the seabed that were colonised post-mortem by both encrusters and borers. Nebelsick et al (1997) noted that encrustation of dead echinoid tests, although they are less robust than mollusc shells, is rather common in the fossil record.…”