title: First radioisotope (potassium-argon) age of marine neogene rionegro beds in northeastern patagonia, Argentina.
abstract: An average age of 9.41 million years was obtained from radioisotope (potassium-argon) age determinations of three glass concentrates of a tuff from the upper part of the marine Rionegrense at Punta Cracker in Golfo Nuevo, Argentina. This age correlates with the Tortonian marine stage of Europe and the Chasicoan Land Mammal Age of South America.
authors.forename: W J
authors.initials: WJ
authors.lastname: Zinsmeister
authors.forename: L G
authors.initials: LG
authors.lastname: Marshall
authors.forename: R E
authors.initials: RE
authors.lastname: Drake
authors.forename: G H
authors.initials: GH
authors.lastname: Curtis