The Mulde event
Graptolites are all but annihilated — 95% of species gone.
- When
- Known to
- ± 2 million years
- Era
- Silurian, Paleozoic
Around 424 million years ago a second Silurian anoxic crisis strikes, hitting the plankton hardest: roughly 95% of graptolite species disappear. Conodonts and shelly faunas suffer too. Because graptolites are the primary tool for dating Silurian rock, the event is unusually well resolved, and it shows how sharply open-ocean ecosystems could collapse and rebuild.