Walter Alvarez

Assembled from 14 blocks · 1 evidence · 5 related

1. Story
2. American geologist whose fieldwork on the Cretaceous–Palaeogene boundary section at Gubbio led, with his father the physicist Luis Alvarez and the Berkeley nuclear chemists Frank Asaro and Helen Michel, to the 1980 proposal that a large asteroid impact caused the extinction. The collaboration is worth attending to as a piece of scientific method: the geological question was Walter's, the idea of using iridium as a chronometer was Luis's, and the measurement capability was Asaro and Michel's neutron-activation laboratory. None of the four could have produced the result alone, and the hypothesis was resisted for most of the following decade by parts of the palaeontological community, partly on the reasonable ground that the fossil record around the boundary appeared to show a more gradual decline than an instantaneous catastrophe implies. Alvarez later wrote a first-hand account of the episode in T. rex and the Crater of Doom (1997).
3. Knowledge
4. Walter Alvarez
5. The Alvarez impact hypothesis is published
6. Connections
7. The Alvarez impact hypothesis is published
8. The Alvarez impact hypothesis is published
9. Walter Alvarez
10. The Cretaceous–Palaeogene iridium anomaly
11. Bottaccione Gorge, Gubbio
12. Walter Alvarez
13. Evidence
14. Supports the iridium anomaly at Gubbio and Stevns Klint, the siderophile-depletion reasoning and the inference of an impactor about ten kilometres across. V55 verification basis: this session had no network access to any source — WebFetch was egress-blocked and the WebSearch budget was exhausted — so the cited work was not retrieved and its pagination was not re-checked. Volume and page range are quoted from standing knowledge and were not re-checked.