Biostratigraphy and evolution of Late Carboniferous and Early Permian smaller foraminifers from the Barents Sea (offshore Arctic Norway)

Abstract

Nearly continuous cores from a 500-meter interval of upper Moscovian through post-Artinskian carbonate strata on the Finnmark Platform have yielded rich assemblages of fusulinaceans and smaller foraminifers. The fusulinaceans provide an independent time framework for evaluating stratigraphic occurrences of associated smaller foraminifers. Information derived from this study has been integrated with that from previous investigations to produce a smaller foraminiferal biostratigraphic model for the High Arctic. Kasimovian strata are characterized by occurrences of Nodosinelloides spp., Protonodosaria spp. and Hemigordius schlumbergeri. Overlying lower Gzhelian beds are identified by the appearances of Raphconilia modificata and Amphoratheca iniqua. Tezaquina clivuli and Cribrogenerina gigas first occur in upper Gzhelian strata, and Asselian rocks contain appearances of Geinitzina postcarbonica and Pachyphloia spp. Phylogenetic reconstructions suggest that the Late Carboniferous-Early Permian pseudovidalinids (Archaediscacea) derived from the Pseudoammidiscidae, as did the older group of predominantly Early Carboniferous archaediscaceans. The repeated development of similar morphologies within the two groups of archaediscaceans includes examples of both convergence and iterative evolution. The Protonodosariidae and Syzraniidae most likely evolved from an earlandiid ancestor. The syzraniids gave rise to the Geinitzinidae, which in turn gave rise to the Pachyphloiidae. As in the archaediscaceans, evolution within and among the Earlandiidae, Protonodosariidae, Syzraniidae, Geinitzinidae and Pachyphloiidae includes multiple examples of repeated patterns. Two key phenotypic developments seemingly led to bursts of diversification in different groups throughout late Paleozoic foraminiferal evolution. The acquisition of an outer hyaline or pseudofibrous wall layer was a morphologic breakthrough followed by taxonomic radiation in both groups of archaediscaceans and in the Earlandia-Syzrania lineage. The second major event was the shift from an undivided tubular morphology to uniserial morphology in both the Earlandiidae-Protonodosariidae and Syzraniidae-Geinitzinidae lines. Nodosinelloides pinardae is proposed as a new name for Nodosaria grandis Lipina, 1949 (preoccupied).

Sequence stratigraphy of the inner Finnmark carbonate platform (Upper Carboniferous-Permian), Barents Sea - correlation between well 7128/6-1 and the shallow IKU cores

“…Appendix 2 is based on a new set of 79 fusulinid-bearing samples from well 7128/ 6-1 which were collected by I. Nilsson and analyzed by V. I. Davydov. This represents a partial revision of previous 7128/6-1 fusulinid biostratigraphy by Nilsson (1992), Wahlman et al (1995), and Groves & Wahlman (1997). Dating of the IKU cores is based on fusulinid biostratigraphy by Nilsson (1993), which was summarized in Bugge et al (1995).…”

New data (smaller foraminifers and correlation with depositional sequences) on the Las Llacerias section (Late Pennsylvanian, Cantabrian Mountains, NW Spain)

“…A similar tendency to ignore them has been common in studies on Pennsylvanian rocks, although some authors have progressively provided information on the Pennsylvanian smaller foraminifers (e.g. Reitlinger 1950;Adachi 1985;Groves 1992Groves , 2000Mamet and Pinard 1992;Brenckle and Wahlman 1994;Altiner and Savini 1995;Henderson et al 1995;Groves and Wahlman 1997;Pinard and Mamet 1998;Vachard and Krainer 2001a). However, the diversity, actual distribution and precise stratigraphic range of Pennsylvanian smaller foraminifers is relatively poorly known.…”

Foraminifers from the Treskelodden Formation (Carboniferous–Permian) of south Spitsbergen

“…Deductions from above presented study were compiled with results of previous investigations to produce the small foraminiferal biostratigraphic model for the High Arctic (e.g. Groves and Wahlman 1997;Pinard and Mamet 1998).…”