See more from this Division: General Discipline Sessions
See more from this Session: Sediments, Carbonates / Clastic
Abstract:
The overall mud-rich facies of the Björkåsholmen Formation reflects deposition on a low-inclined ramp environment. Coarse-grained sediments represent the proximal facies while increasing mud content shows deeper water middle to outer ramp deposition. Facies trends indicate that the Björkåsholmen Formation consists of at least five regressions and successive transgressions with a maximum lowstand represented by its coarse-grained central portion. As the Björkåsholmen Formation is sandwiched between two prominent outer shelf shales in the Norwegian and westernmost Swedish localities it also represents the most pronounced sea-level lowstand in the Early Ordovician of Scandinavia. This lowstand is within the upper part of the Aorograptus victoriae Biozone and the basal Kiaerograptus supremus Biozone. Deposition of the Björkås¬holmen Formation therefore likely represents a fairly short time-span. However, this remarkably strong lowstand in Scandinavia is not paralleled by base-level falls in Bolivia, China or Newfoundland. It is therefore suggested that the Björkås¬holmen Formation reflects a tectonic rather than a eustatic event which is restricted exclusively to Baltoscandia
See more from this Division: General Discipline Sessions
See more from this Session: Sediments, Carbonates / Clastic