RUPELIAN STAGE

all those rocks deposited worldwide during the Rupelian Age (36.6 to 30 million years ago). The Rupelian is the earlier of two stages in the Oligocene Series and comprises the Lower Oligocene. It was named for exposures studied along the Rupel, a tributary of the Scheldt River in Belgium. This area formerly served as the type district for the stage. The global stratotype section and point (GSSP) for the Rupelian's base is now established in the Marchigiano Basin of Italy. The foraminifera that serve as indexes for this stage include Pseudohastigerina micra and Cassigerinella chipolensis. Certain species of radiolarians and calcareous nannofossils are also used to correlate the stage's occurrences in different locations. The Rupelian Stage is overlain by the Chattian Stage.