Integration of Darriwilian (Middle Ordovician) delta C-13(org) chemostratigraphy with graptolite biostratigraphy in the classical Rostanga area in northwestern Scania (southern Sweden)

Abstract

The largely covered Middle Ordovician succession in the classic geological Rostanga area in northwestern Scania has not been studied for some 80 years. A new drill core through a succession ranging from the lower-middle Darriwilian to the lower Sandbian has provided a unique opportunity to investigate the graptolite biostratigraphy and the delta C-13(org) chemostratigraphy, and clarify their stratigraphic relations, through this similar to 90 m thick interval, which is developed within a black shale facies. The lithology, biostratigraphy and chemostratigraphy are closely similar to those of the coeval strata in the FAgelsAng area, south-central Scania, including the presence of the Fagelsang Phosphorite. which was previously unrecorded in the Rostanga area. The new data are particularly important in providing evidence of the relations between graptolite biostratigraphy and delta C-13(org) chemostratigraphy. The Fagelsang-3 and Rostanga-2 drill core successions are currently the only Darriwilian sequences in the world where these relations have been well established.