The Jurassic-Cretaceous transition of the Fararp-1 core, southern Sweden: Sedimentological and phytological indications of climate change

• Published in: Palaeogeography, Palaeoclimatology, Palaeoecology
• Main Authors: Lindström, Sofie, Erlström, Mikael
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2011
• Subjects: Geology; Palynology; Clay mineralogy; Climate change; Berriasian; Valanginian: Jurassic-Cretaceous boundary; Fennoscandian
• Online Access: https://lup.lub.lu.se/record/2159176; https://doi.org/10.1016/j.palaeo.2011.05.052

The 116m deep Fararp-1 core drilled in the Vomb Trough in southernmost Sweden is dated by integrated terrestrial and marine palynostratigraphy. The lower part of the succession (ca 84 m) encompasses uppermost Jurassic to lowermost Cretaceous (uppermost Tithonian to Valanginian) strata. An unconformity separates the Valanginian strata from an overlying ca 1 m thick interval of upper Albian to Cenomanian Arnager Greensand Formation. The uppermost part of the core is a repetitive succession of lowermost Cretaceous sediments. During the Jurassic-Cretaceous U/K) transition NW Europe was located in mid latitudes, and comprised an archipelago of large and small islands separated by deeper grabens and epicontinental seaways that connected the Boreal Sea to the north with the warmer Tethys Ocean to the south. Boundary strata in England, France, the Netherlands and Germany are characterised by relatively prominent climatic change from arid/semi arid to subhumid/humid conditions. Southernmost Sweden was located on the margin of a large landmass comprising most of the Fennoscandian Shield bordering a large epicontinental sea to the west. By combining sedimentology, clay mineralogy and palynofacies the Tithonian to Valanginian cored succession of the Fararp-1 core provides complementary information on how marginal deposits from the eastern part of the epicontinental sea reflect the climatological and environmental changes observed in other parts of NW Europe. The Fararp-1 core shows that during the Tithonian to earliest Berriasian deposition took place in a terrestrial but near-marine depositional setting, in coastal lakes or lagoons with little marine influence. A dry climatic regime favoured stagnant water conditions with common algal blooms of primarily Bonyococcus and zygnemataceae. Palynofacies and sedimentology indicate limited transport of freshwater and material to the basin. The stagnant depositional environment was terminated by a marine flooding in the early Berriasian. During the remaining Berriasian and the ...