Kristina Mehlqvist

A Jurassic (Pliensbachian) flora from Bornholm, Denmark - a study of a historic plant-fossil collection at Lund University, Sweden

A historic collection of plant fossils from the Bagå Formation, Bornholm, Denmark registered at the Lund University is reviewed and found to be dominated by ferns with subsidiary Ginkgoales, Coniferales, Bennettitales and Equisitales. Ten genera are represented, of which six can be confidently identified to species level. The Bagå Formation flora is most similar in age to the flora of the Middle Jurassic Mariedals Formation of Eriksdal, Skåne, although there are important compositional differences between these assemblages. The Bagå flora is characteristic of the temperate (warm and humid) biome of the Early–mid Jurassic. A historical investigation reveals that at least four scientists contributed material to the collections. A palynological investigation made on samples from the leaf fossils reveals that the macroflora was most probably collected from the Sorthat beds as the palynoflora corresponds to the Pliensbachian Chasmatosporites Zone.

Early land plant spore assemblages from the Late Silurian of Skane, Sweden

A palynological study based on sedimentary rocks (mainly calcareous siltstones and mudstones with minor carbonate beds) from the upper Silurian Öved-Ramsåsa Group in the Klinta 1 and Bjärsjölagård 2 drillcores, Skåne, Sweden, reveals a rich assemblage of well-preserved spores produced by early land plants. Thirty-four spore taxa belonging to 19 genera, including the new species Scylaspora klintaensis sp. nov., were identified. The palynoflora is characterized by cryptospores and trilete spores. The dominant spore species are the cryptospores Gneudnaspora plicata followed by Gneudnaspora divellomedia. Based on the presence of biostratigraphically important spore species such as Hispanaediscus lamontii, Artemopyra radiata, Emphanisporites neglectus, Synorisporites cf. libycus and Synorisporites tripapillatus, the age of the studied strata is interpreted to be of a Late Silurian age. Although the palynological assemblages are strongly dominated by miospores and other land plant fragments, marine microfossils are also present and the sedimentary succession is interpreted to have been deposited in a nearshore marine environment.

Late Ordovician (Katian) spores in Sweden: oldest land plant remains from Baltica

A palynological study of the Ordovician–Silurian boundary (Katian–Rhuddanian) succession in the Röstånga-1 drillcore, southern Sweden, has been performed. The lithology is dominated by mudstone and graptolitic shale, with subordinate limestone, formed in the deeper marine halo of southern Baltica. The palynological assemblages are dominated by marine microfossils, mainly chitinozoans and acritarchs. Sparse but well-preserved cryptospores, including Tetrahedraletes medinensis, Tetrahedraletes grayii and Pseudodyadospora sp., were encountered in the Lindegård Formation (late Katian–early Hirnantian), with the oldest record just above the first appearance of the graptolite species Dicellograptus complanatus. This represents the earliest record of early land plant spores from Sweden and possibly also from Baltica and implies that land plants had migrated to the palaeocontinent Baltica by at least the Late Ordovician.

A palynological study from Sweden reveals stable terrestrial environments during Late Silurian extreme marine conditions

A palynological study of the upper Silurian Oved-Ramsasa Group in Skane, Sweden yields a well preserved spore assemblage with low relative abundances of marine microfossils. In total, 26 spore taxa represented by 15 genera were identified. The spore assemblage is dominated by long-ranging cryptospore taxa, and the trilete spore Ambitisporites avitus-dilutus. However, key-species identified include Artemopyra radiata, Hispanaediscus lamontii, H. major, H. verrucatus, Scylaspora scripta and Synorisporites cf. libycus. Importantly, Scylaspora klintaensis was identified, allowing correlation with the Klinta 1 drillcore (Skane). A Ludlow age is inferred for the exposed succession, which agrees well with previous conodont stratigraphy. The organic residue is dominated by phytodebris and spores, but with high relative abundances of acritarchs at two levels, possibly related to flooding surfaces. Based on the palynofacies analysis, a near-shore marine environment is proposed. The close proximity to land is inferred by the high proportions of spores, and the dispersed assemblage most likely represents the local flora growing on delta plains. The palynological signal also infers a stable terrestrial environment and vegetation, in contrast to unstable conditions in the marine environment characterised by ooid formation in an evaporitic environment. Comparisons with coeval spore assemblages from Gotland, Avalonia and Laurentia show relatively close similarities in taxonomic composition at the generic level. (Less)

Lundadagarna i Historisk Geologi och Paleonotologi XII 17–18th of March, 2011

Lundadagarna i Historisk Geologi och Paleontologi is a conference held every second year at the Department of Earth and Ecosystem Sciences, Division of Geology, Lund University. Since the start in 1989, Lundadagarna has been an important opportunity for researchers from Scandinavia to get updated on the direction of the research field and new results, as well as a forum for discussing projects and exchanging ideas. As always, we are happy to announce a wide range of talks and posters within the field of historical geology and palaeontology. This year 35 participants contributed with 17 talks and 7 posters during Lundadagarna XII, 17–18th of March 2011. We would like to thank all participants for their contribution.