Cretaceous foraminiferal morphogroup distribution patterns, palaeocommunities and trophic structures: a case study from the Sergipe Basin, Brazil

Abstract

Foraminiferal studies have been used in palaeo-environmental reconstructions of the marine Cretaceous succession (upper Aptian to Maastrichtian) of the Sergipe Basin, in northeastern Brazil. The foraminiferal assemblages show broadly three types of response to changes in environment: (1) variations in morphotypes of the taxa present; (2) changes in specific and generic diversity; and (3) changes in relative abundance.Twelve palaeocommunities, characterised by the relative dominance of the major foraminiferal groups, can be recognised in the succession. Their palaeoenvironmental distribution is proposed as a model with reference to the Sergipe Cretaceous sequence.An intimate relationship is inferred among foraminiferal association distribution patterns, trophic structures (community feeding strategy, dwelling habits, substrate niche patterns) and water-mass conditions (depth-related in part). It is suggested that the distribution patterns may be a direct response of the functional adaptive morphology of the foraminiferal tests to individual characteristics of behavioural structure (preferential dwelling microhabitat and trophic strategy versus environment). The approach is a simple, yet very powerful tool, for the interpretation of foraminiferal palaeocommunities and palaeoceanographic research. It may also permit interpretation of palaeocommunity strategies in terms of adaptation rate and selection response (i.e. “r-selection” versus “k-selection”) to variable environmental conditions.

Biostratigraphy and paleoecology of the Lower Cretaceous sediments in the Outer Western Carpathians (Silesian Unit, Czech Republic)

“…Lenticulina, Astacolus and Saracenaria together with high conical trocholinids (Trocholina and Turrispirillina) are relatively common in the deposits of both quarries. They represent epifaunal depositfeeders typical of neritic environments (Koutsoukos & Hart 1990). Inner to middle shelf environments of the Early Albian age are characterized mainly by Marssonella (Koutsoukos & Hart 1990).…”

“…They represent epifaunal depositfeeders typical of neritic environments (Koutsoukos & Hart 1990). Inner to middle shelf environments of the Early Albian age are characterized mainly by Marssonella (Koutsoukos & Hart 1990). These autors defined several morphogroups according to the shape of foraminiferal tests and used them for a paleoenvironmental reconstruction of the Cretaceous marine successions.…”

Site U1346

“…Bolli et al (1994) and Holbourn and Kaminski (1997) attributed the latter seven genera to the family Vaginulinidae. The nodosariids (or nodosariids and vaginulinids) have been known to dominate in the neritic to upper bathyal setting (e.g., Sliter and Baker, 1972;Sliter, 1977;Koutsoukos and Hart, 1990). Accordingly, the estimated paleodepth for stratigraphic Unit IV (see "Sedimentology") of Site U1346 is ≤500 mbsl.…”

Foraminíferos planctônicos e bentônicos cretáceos da Ilha de Quiepe, Formação Algodões, Bacia de Camamu, Bahia, Brasil

“…Koutsoukos, 1989Koutsoukos, , 1992Koutsoukos & Hart, 1990;Silva, 2007Silva, , 2011. Estudos aplicando os foraminíferos como indicadores bioestratigráficos, paleoambientais e paleoceanográficos foram realizados na Bacia de Sergipe, compreendendo uma revisão taxonômica dos foraminíferos planctônicos e bentônicos do intervalo Aptiano superiorMaastrichtiano (Koutsoukos, 1989).…”

“…A revisão se estendeu para o zoneamento bioestratigráfico da bacia, obtido a partir dos foraminíferos planctônicos, onde também foram abordados aspectos paleoecológicos e reconhecidas associações e morfogrupos. Esses dados foram integrados às particularidades sedimentológicas da bacia, tornando possível a proposição de modelos paleoambientais para a área estudada (Koutsoukos, 1989(Koutsoukos, , 1992Koutsoukos & Hart, 1990).…”