The results of the iridium analysis were surprising. The team found more than 30 times what they had expected.
Image use policy: For non-commercial, educational purposes, this image may be used with a Creative Commons CC BY-NC-SA 4.0 license. Please credit as follows: © University of California Museum of Paleontology, Understanding Science, www.understandingscience.org
See where this image appears on the Understanding Science website »