Ordovician Glaciation/Extinction Roundup

I found a bunch of new and new-ish work on the end-Ordovician extinction

Commentary, with a large bibliography.

Now we’re up to at least 6 potential causes:

  1. Evolution and expansion of land plants
  2. Asteroid impact
  3. Large scale volcanism
  4. Dust from L-chondrite parent body breakup
  5. Gamma ray burst
  6. “True Polar Wander”

Three putative causes are extra-terrestrial. The “True Polar Wander” cause is just weird.

True Polar Wander:

true polar wander (TPW) is the movement of the entire solid Earth (mantle and crust) relative to Earth’s spin axis in order to stabilize Earth rotation.

Since this is paleontology, automatic gainsaying of every theory occurs: the mass extinction might not have been so massive, and maybe was quite short. Maybe there was large scale volcanism, and maybe there wasn’t. Maybe the oceans were cool, and maybe they weren’t.

I don’t know about you, but I intend to keep following this drama.