Sorthat Formation
| Sorthat Formation | |
|---|---|
| Stratigraphic range: Latest Pliensbachian to Latest Toarcian ~Possible Lower Aalenian layers | |
Korsodde section of the Sorthat Formation, where the local Toarcian anoxic event stratum is located | |
| Type | Geological formation |
| Unit of | Bornholm Group |
| Sub-units | Sorthat & Levka beds |
| Underlies | Bagå Formation |
| Overlies | Rønne & Hasle Formations |
| Thickness | 240 m (790 ft) |
| Lithology | |
| Primary | Claystone, sandstone |
| Location | |
| Coordinates | 55°05′N 14°25′E / 55.09°N 14.42°E |
| Approximate paleocoordinates | Approx. 35°N |
| Region | Bornholm
|
| Country | Denmark, Germany (ex situ sandstones) |
| Type section | |
| Named for | Sorthat-Muleby, Bornholm |
| Named by | Gry (as part of the Bagå Formation) |
| Year defined | 1969 |
The Sorthat Formation is a geologic formation on Bornholm, Denmark, and the Rønne Graben, Baltic Sea, from the Latest Pliensbachian to Late Toarcian. It holds plant fossils and invertebrate traces, overlain by fluvial and lacustrine deposits of the Aalenian-Bathonian Bagå Formation. Initially part of the Bagå Formation until 2003, it spans the Latest Pliensbachian to Early Aalenian. It reflects a deltaic to marine setting with eastern river systems forming in the Toarcian. Early Pliensbachian volcanism from southern Sweden extended across the North Sea. The Central Skåne Volcanic Province and Egersund Basin contributed volcanic material, affecting tectonics. Early Jurassic porphyritic nephelinite lavas in the Egersund Basin, akin to those in the formation’s clay pits, suggest fluvial sediment transport to the Grimmen Formation and Ciechocinek Formation. The Grimmen Formation is its sister unit.