Oligocene dinoflagellate cysts from the North Alpine Foreland Basin: new data from the Eggerding Formation (Austria)In spite of detailed geological and geophysical investigations, information available on palynostratigraphy for the successions deposited in the Austrian part of the North Alpine Foreland Basin (NAFB) is scanty. For the first time, relatively diverse and well preserved Oligocene dinocyst assemblages, comprising 53 genera and 138 species, are presented from the organic-rich sediments of the Eggerding Formation. These assemblages contribute to the biostratigraphy of the Oligocene deposits within the NAFB. Dinocysts such asChiropteridium lobospinosum, Membranophoridium aspinatum, Cordosphaeridiumspp.,Enneadocystaspp.,Deflandreaspp.,Spiniferites/Achomosphaeragroup,Hystrichokolpomaspp.,Apteodiniumspp.,Glaphyrocysta/Areoligeracomplex andWetzeliellaspp. represent the main palynological elements. The occurrence ofChiropteridiumspp.,Tuberculodinium vancampoae, Distatodinium biffiiandWetzeliella gochtiiis of particular importance for regional correlations within the Lower Oligocene sediments. A comparison with age-controlled assemblages from the North Sea Basin, Carpathian and circum-Mediterranean regions substantiate the attribution to the Rupelian. Lack or sporadic occurrence of the oceanic taxa (e.g.NematosphaeropsisandImpagidinium) and dominance ofGlaphyrocysta/Areoligeraindicate an inner-neritic marine setting during the deposition of the studied intervals. Although, it is difficult to reconstruct precisely the climatic conditions based on the recorded dinocysts, warm? sea surface water is suggested. A variation in salinities is interpreted based on the abundances ofHomotrybliumspp. The abundance of Peridiniaceae taxa (e.g.Lejeunecysta, Wetzeliella, and Deflandrea) indicates nutrient-rich surface water.
Oligocene dinoflagellate cysts from the North Alpine Foreland Basin: new data from the Eggerding Formation (Austria)
