The end-Permian mass extinction

Assembled from 43 blocks · 2 evidence · 20 related

1. Story
2. The largest known biotic crisis, removing on published estimates somewhere between roughly 80 and 96 per cent of marine species depending on the analysis and the method, and unusually severe on land as well — it is the only mass extinction known to have caused a major loss of insect families. Whole groups that had dominated Palaeozoic seafloors for two hundred million years, including the trilobites, disappear at or near this horizon. The dating from the Meishan reference section in Zhejiang is what makes the event tractable: uranium–lead ages on zircons from ash beds interbedded with the boundary limestone place the boundary at 251.902 ± 0.024 million years and constrain the main extinction pulse to roughly sixty thousand years. The Siberian Traps flood basalts are contemporaneous within the resolution of the dating, and the favoured mechanism is not the lava but the gases released when those magmas intruded coal, evaporite and carbonate sequences — carbon dioxide and methane driving warming, ocean anoxia and acidification. Recovery of ecosystem complexity took several million years, longer than after any other extinction.
3. Knowledge
4. Radiometric dating
5. Mass extinction
6. Meishan GSSP, Changxing, Zhejiang
7. Siberian Traps large igneous province
8. The end-Permian mass extinction
9. The end-Triassic mass extinction
10. Connections
11. Meishan GSSP, Changxing, Zhejiang
12. Siberian Traps large igneous province
13. Mass extinction
14. The end-Triassic mass extinction
15. Meishan GSSP, Changxing, Zhejiang
16. Radiometric dating
17. The Late Devonian crisis
18. The end-Permian mass extinction
19. The end-Permian extinction is resolved to about sixty thousand years
20. Radiometric dating
21. The end-Permian mass extinction
22. The Cretaceous–Palaeogene mass extinction
23. The end-Ordovician mass extinction
24. The Late Devonian crisis
25. The end-Triassic mass extinction
26. The end-Permian mass extinction
27. Central Atlantic Magmatic Province
28. Mass extinction
29. The Cretaceous–Palaeogene mass extinction
30. The end-Permian mass extinction
31. Global Boundary Stratotype Section and Point
32. The end-Permian mass extinction
33. The end-Permian extinction is resolved to about sixty thousand years
34. Mass extinction
35. Zircon as a geochronometer
36. Molecular clock dating
37. The end-Permian mass extinction
38. Sulfur mass-independent fractionation is proposed as an atmospheric oxygen proxy
39. The K–Pg boundary is dated to 66.043 ± 0.043 Ma
40. The end-Permian extinction is resolved to about sixty thousand years
41. Evidence
42. Supports the Permian–Triassic boundary age of 251.902 ± 0.024 Ma from Meishan zircons and the constraint of the main extinction pulse to roughly sixty thousand years. 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.
43. Supports the stage and period boundary ages used throughout this pack, including the Cambrian base at 538.8 ± 0.2 Ma on recent editions against 541.0 ± 1.0 Ma on earlier ones. 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. No chart edition was opened, so the boundary figures are quoted from standing knowledge of the chart rather than read from it, and the edition in which the Cambrian base changed is not identified.