Geographiske chartor öfver Sverige - Charta öfver... Finland - 4 : Storfurstendömet Finland

Stockholm 1799, Graverad af Fr. Akrel1 Charta öfver Savolax... digitoitu toisesta teoksesta.1 Nimiösivun kuva - Picture on title-page: Utsigt ifrån Wermasvuori åt sjöarne Jokijärvi och Ilmolanselkä uti Hauho sockn i Nylands och Tavastehus höfdingedöm

Palynostratigraphy of dinosaur footprint-bearing deposits from theTriassic–Jurassic boundary interval of Sweden

The Triassic–Jurassic boundary (c. 200 Ma) marks one of the five largest Phanerozoic mass extinction events and is characterized by a major turnover in biotas. A palynological study of sedimentary rock slabs bearing dinosaur footprints from Rhaeto–Hettangian strata of Skåne, Sweden was carried out. The theropod dinosaur footprints (Kayentapus soltykovensis) derive from the southern part of the abandoned Vallåkra quarry (Höganäs Formation) and were originally dated as earliest Jurassic (Hettangian) based on lithostratigraphy. Our results reveal that two of the footprints are correlative with the latest Triassic (latest Rhaetian) disaster zone typified by a high abundance of the enigmatic gymnosperm pollen Ricciisporites tuberculatus and Perinopollenites elatoides together with the key taxon Limbosporites lundbladii and fern spores. Two footprints are dated to correlate with the Transitional Spore-spike Interval. One footprint is interpreted as Hettangian in age based on the relatively high abundance of Pinuspollenites spp. together with the presence of the key taxa Retitriletes semimuris and Zebrasporites intercriptus. Our new palynological study suggests that the Kayentapus ichnogenus already appeared in the end of Triassic, and our study highlights the use of palynology as a powerful tool to date historical collections of fossils in museums, universities and elsewhere. The Hettangian footprint reflects a marine influence while all other studied ichnofossil specimens occur in non-marine (floodplain and delta interdistributary) sediments. The sediments associated with the Hettangian footprint include a significant proportion of charcoal transported from land after wildfires. The Rhaeto–Hettangian vegetation was otherwise characterized by multi-storey gymnosperm–pteridophyte communities

Onshore Jurassic of Scandinavia and related areas

Jurassic strata are extensively distributed in offshore areas of Scandinavia, but onshore exposures are mostly restricted to southern Sweden (Skane), the Danish island of Bornholm, East Greenland, northern Norway (Andoya) and Svalbard. The latest Triassic and Jurassic saw active tectonism in Scandinavia associated with the break-up of Pangaea and rifting in the North Atlantic region and the North Sea. Rifting and the gradual rise in sea level controlled the structural and sedimentological architecture of Scandinavian basins throughout the Jurassic. The Upper Triassic is represented by continental red beds (claystones and arkosic conglomerates) indicative of arid conditions (until the Norian) and by coal measures characteristic of humid conditions (in the Rhaetian). Early Jurassic sedimentation in the region was dominated by fluvial-estuarine systems. Basin subsidence combined with the supply of huge volumes of sediments led to the accumulation of thick sand units on vast coastal plains in the Early and Middle Jurassic. During the Late Jurassic, transgressions led to deposition of extensive marine mud, although sandstones are locally preserved. Paralic depositional environments prevailed during the Late Jurassic and into the Early Cretaceous in southern Scandinavia. Scandinavia hosts a rich Jurassic palaeontological record including fossil plants, sharks, dinosaur footprints, ammonites, belemnites, ichthyosaurs and pliosaurs. Miospores provide the primary tool for biostratigraphic subdivision and correlation of the continental Jurassic sediments, whereas ammonites, dinoflagellates and foraminifera are the main groups employed for marine biostratigraphy. However, much work remains to be completed to achieve a highly resolved zonation scheme that integrates both marine and terrestrial indices