"Fern spore abundance across the K / T boundary at Morgan Creek, Saskatchewan, and iridium concentrations, showing a large increase in relative spore abundance - a fern-spore spike - coincident with the iridium anomaly." (Price 1996). An increase in the relative abundance of ferns is consistent with a decline in the relative numbers of angiosperms, as would be expected in the "nuclear winter" scenario of an asteriod impact at the K / T boundary.

Text material © 2005 by Steven M. Carr