title: An iridium abundance anomaly at the palynological cretaceous-tertiary boundary in northern new Mexico.
abstract: An iridium abundance anomaly, with concentrations up to 5000 parts per trillion over a background level of 4 to 20 parts per trillion, has been located in sedimentary rocks laid down under freshwater swamp conditions in the Raton Basin of northeastern New Mexico. The anomaly occurs at the base of a coal bed, at the same stratigraphic position at which several well-known species of Cretaceous-age pollen became extinct.
authors.forename: C J
authors.initials: CJ
authors.lastname: Orth
authors.forename: J S
authors.initials: JS
authors.lastname: Gilmore
authors.forename: J D
authors.initials: JD
authors.lastname: Knight
authors.forename: C L
authors.initials: CL
authors.lastname: Pillmore
authors.forename: R H
authors.initials: RH
authors.lastname: Tschudy
authors.forename: J E
authors.initials: JE
authors.lastname: Fassett