The Alvarez impact hypothesis is published

Assembled from 24 blocks · 1 evidence · 6 related

1. Story
2. Luis Alvarez, Walter Alvarez, Frank Asaro and Helen Michel published in Science the measurement of anomalously high iridium in the boundary clay at Gubbio and Stevns Klint, and the inference that a body about ten kilometres across had struck the Earth and injected enough dust into the stratosphere to suppress photosynthesis. The paper is unusual in that its central evidence is a single element abundance rather than a fossil or a structure, and the argument depends on a fact about planetary differentiation rather than about biology. It was resisted for most of the following decade, partly because no crater was known, partly because it looked like catastrophism, and partly because sampling of the fossil record near the boundary appeared at the time to show a gradual decline — an appearance later attributed in large measure to the difficulty of sampling the last occurrence of a rare species.
3. Knowledge
4. The Cretaceous–Palaeogene iridium anomaly
5. Bottaccione Gorge, Gubbio
6. Walter Alvarez
7. The Alvarez impact hypothesis is published
8. Connections
9. Walter Alvarez
10. The Cretaceous–Palaeogene iridium anomaly
11. Bottaccione Gorge, Gubbio
12. Walter Alvarez
13. The Cretaceous–Palaeogene mass extinction
14. Bottaccione Gorge, Gubbio
15. The Cretaceous–Palaeogene mass extinction
16. The Alvarez impact hypothesis is published
17. Chicxulub is identified as the K–Pg impact crater
18. The Cretaceous–Palaeogene iridium anomaly
19. The Cretaceous–Palaeogene mass extinction
20. The Alvarez impact hypothesis is published
21. The Alvarez impact hypothesis is published
22. The Alvarez impact hypothesis is published
23. Evidence
24. 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.