The Almelund Shale, a replacementname for the Upper Didymograptus Shale and the Lower Dicellograptus Shale in the lithostratigraphical classification of the Ordovician succession in Scania, Southern Sweden

Abstract

The formation name Almelund Shale is proposed for a lithostratigraphically defined unit to replace the outdated chronostratigraphical designations Upper Didymograptus Shale and Dicellograptus Shalein the Middle and lowermost Upper Ordovician succession in Scania. The Almelund Shale is a lithologically uniform unit of dark-grey to black shales with rare carbonate interbeds between the Komstad Limestone and the Sularp Shale. Apart from a diverse graptolite fauna it yields a few shelly fossils (mostly lingulate brachiopods) and biostratigraphically diagnostic conodonts and chitinozoans. In the type sections of the Almelund Shale along the Sularp Brook in the Fågelsång area, W-central Scania, the top of the unit is taken to be the base of the Fågelsång Phosphorite, and its basal contact is at the top of the underlying Komstad Limestone. Its total thickness in the Fågelsång drill-core is 28.32 m. The unit is widely distributed in the subsurface in a SE-NW belt across Scania.