Iridium is a very rare element in the Earth's crust, but is found in anomalously high concentrations (around 1000 times greater than normal) in a thin worldwide layer of clay marking the boundary between the Cretaceou…
Following up on No. 14206, the authors stated that the same excess iridium areas were found in two different areas of W. Europe and in New Zealand, and posited that “the anomalous iridium concentrations at the C [reta…
Eleven years after publication of No. 14207, Alan Hildebrand, working with Luis and Walter Alvarez, proposed that the Chicxulub Crater, discovered by Antonio-Camargo-Zanoguera and Glen T. Penfield during the 1970s, wa…
"... emphasizes the importance and interrelationships of geological processes to the health and diseases of humans and animals. Its accessible format fosters better communication between the health and geoscience comm…
