Palynological and Iridium Anomalies at Cretaceous-Tertiary Boundary, South-Central Saskatchewan

Science  14 Feb 1986:
Vol. 231, Issue 4739, pp. 714-717
DOI: 10.1126/science.231.4739.714


The Cretaceous-Tertiary boundary in south-central Saskatchewan is marked by coincident anomalies in abundance of iridium and fern spores at the extinction level of a suite of Cretaceous pollen taxa. Evidence of disruption of the terrestrial flora includes the fern-spore abundance anomaly and local extinction of as much as 30 percent of angiosperm species. The reorganized earliest Tertiary flora is made up largely of surviving species that assumed new roles of dominance. Persistence of climatically sensitive taxa across the boundary indicates that if paleoclimate was altered by the terminal Cretaceous event, it returned quickly to the pre-event condition.