An iridium abundance anomaly at the palynological cretaceous-tertiary boundary in northern new Mexico.
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.
Orth
C J
CJ
Gilmore
J S
JS
Knight
J D
JD
Pillmore
C L
CL
Tschudy
R H
RH
Fassett
J E
JE