Calcareous Nannofossils from the La Barca Formation (Paleocene/Eocene Boundary), Tierra Del Fuego, Argentina

The La Barca Formation, an organic-carbon rich sedimentary succession exposed along the Atlantic coast of Peninsula Mitre (Tierra del fuego, Argentina), was initially assigned to the late Paleocene, based on foraminifera and dinocysts. Planktonic foraminifera or calcareous nannofossils were not previously recorded in the two members of this formation. New samples of the upper member provided calcareous nannofossils that correlate with the late Paleocene-early Eocene assemblages in the Southern Hemisphere, spanning nannofossil zones NP9a/NP9b. The Paleocene/Eocene boundary in the La Barca Formation could be placed between the last occurrences of Fasciculithus richardii group and F. alanii, and the first occurrence of Romboaster cf. R. cuspis.