Abstract

The Kapp Starostin Formation is the uppermost Palaeozoic stratigraphic unit in Spitsbergen, ranging from Kungurian to the Tatarian. It contains a cold water adapted fauna dominated by brachiopods, bryozoans and sponges. Four depositional facies are recognised in central Spitsbergen: 1) a cold water carbonate facies on the shallow shelf; 2) a terrigenous sand facies on the deep shelf; 3) a siliceous mud facies on the deep shelf and slope; and 4) a black mud facies in the basin. The cold water carbonates with a limited fauna contain rare non-skeletal carbonate components and carbonate muds and were deposited on a shallow carbonate shelf. The siliceous mudstones, containing numerous sponge spicules, were deposited below normal wave base. At the same depth terrigenous sands with glauconite were distributed in places. The black mudstones are characterised by rare benthic fauna and less bioturbation, implying deposition in a stagnant condition.

The sequence of the Kapp Starostin Formation shows four cyclic facies successions, with several transgressive-regressive couplets from shallow carbonate facies to terrigenous sand, deep siliceous or basinal mud facies and vice versa. The whole sequence comprises one transgressive-regressive cycle commonly observed in the Arctic region.

The organisms of the Kapp Starostin Formation vary in abundance and taxonomic diversity, showing a strong facies dependence. The faunal diversity decreases with increase in water depth and terrigenous sediment content. The Permian fauna shows strong faunal similarities in composition within Arctic and peri-Gondwana regions and flourished temporarily in a colder climate in the northern hemisphere. The fauna, however, disappeared in a tectonic framework established in the mid-Permian. Relative sea level fluctuations coupled with local and regional tectonism induced a marked variety of adverse conditions for the cold water organisms.