Sedimentologi og stratigrafi i permlagrekken, Svalbard
Sedimentary bedrocks of Permian age record an exceptional time period in earth history, known for fundamental climatic, oceanographic and environmental changes in a transitional period from global icehouse to greenhouse conditions. These changes culminated in the end-Permian mass extinction event, a major extinction in earth history, during which about 96 % of all marine invertebrate species disappeared completely, while other groups suffered substantial losses. The causes for this ecological crisis are still under discussion, but major climatic and/or oceanic changes (sea-level, salinity, sea-water chemistry, ocean circulation and anoxia) probably in connection with increased volcanism, a meteorite impact or methane release are discussed to be possible causes.
The project has been initiated in order to clarify uncertainties within the Permian lithostratigraphic record of Svalbard, as well as to improve the general understanding of the climatic, environmental and depositional development during the Permian and the transitional period into the Early Mesozoic. Globally, sedimentary bedrocks comprising the Permian Period and the transition into the Triassic are lacking in most regions. On Svalbard however, Permian strata including the Permian-Triassic boundary (PTB) are well exposed within a number of outcrops.
Investigations focus on the Permian Tempelfjorden Group (Kapp Starostin Formation; ?Artinskian-?Kazanian) and the lowermost strata of the overlying, Early Triassic Sassendalen Group (Vikinghøgda Formation; Induan-Olenekian). The strata of the Kapp Starostin Formation are dominated by spiculitic cherts, with black shales, partly glauconitic sandstones and fossiliferous limestones as minor lithologies, comprising a highly diverse heterozoan biotic assemblage mainly consisting of brachiopods, bryozoans, echinoderms and siliceous sponges as main sediment producer. The facies reflect shallow, open-marine, nearshore areas to distal, deep-marine, basinal offshore areas of a temperate, storm-dominated, mixed quartzitic-carbonate shelf. The Vikinghøgda Formation in contrary consists of fine-grained, siliciclastic marine deposits, including shales and siltstones with subordinate sandstones and carbonate rocks, yielding ammonites and mollusks as main biota. The lithostratigraphic boundary of the two groups is sharp due to the abrupt onset of the fine-grained, siliciclastic deposits of the Sassendalen Group accompanied by the abrupt termination of biotic sediment production characteristic for the Tempelfjorden Group.
Deltakere
Prosjektleder: Dierk Blomeier
Publikasjoner
- Blomeier, D., Carmohn, D., Forke, H. & Scheibner, C. (2010): Environmental change in the Early Permian of Spitsbergen: from a warm-water carbonate platform (Gipshuken Formation) to a temperate, mixed siliciclastic-carbonate ramp (Kapp Starostin Formation).- Facies: DOI 10.1007/s10347-010-0243-z.
- Blomeier, D., Groen, R., Scheibner, C., Forke, H., Carmohn, A., Joachimski, M., Buggisch, W., Grunt, T. & Reijmer, J. (in prep): Facies analysis of the Kapp Starostin Formation on Svalbard: Reconstruction of depositional environments and the Permian sea-level curve for Svalbard.
Samarbeidspartnere
- University of Bremen, Germany (Christian Scheibner)
- University of Erlangen, Germany (Werner Buggisch, Michael Joachimski)
- The Natural History Museum of Berlin, Germany (Holger Forke, Dieter Weyer)
- Geological Survey Schleswig-Holstein, Germany (Christoph Hartkopf-Fröder)
- University of Leeds, United Kingdom (Paul Wignall, David Bond)
- University of Tromsø, Norway (Anna Carmohn)
- Laboratory-studio “Living Earth”, Moscow, Russia (Tatiana Grunt)