Early Jurassic (Pliensbachian-Toarcian) dinoflagellate migrations and cyst paleoecology in the Boreal and Tethyan realms

摘要

The discrepancies in the stratigraphical ranges of selected dinoflagellate cysts recorded in the Boreal and Tethyan realms have revealed two migrational events during the Early Jurassic. The first event occurred at the early-late Pliensbachian boundary and consists of mutual biotic exchanges between the two realms. This is linked to a major Early Jurassic transgression which improved ma- rine communications between the Boreal and Tethyan areas. The second dinoflagellate migratonal event occurred during the mid Toarcian and was driven by paleoenvironmental factors.