Posts tagged clay

The iridium layer, or K/T Boundary

The thin, grey claystone layer contains 1,000 times more iridium (REE) than the layers above and below, along with shocked quartz.  Iridium is extremely rare on Earth, but a very common/abundant element in asteroids.  This layer has been identified in 100+ places around the Earth.

This boundary marks the extinction of the non-avian dinosaurs.

(Source: elegantbuffalo)