On: Trilobites killed by volcanic ash

[webwielder2]

It’s just amazing that fossils even exist. Thanks, random natural events and processes for showing us what the freakin’ distant past looked like!

[imoverclocked → webwielder2]

We even have a record of ancient Earth’s magnetic fields :) The geological record is pretty amazing indeed!

[jjtheblunt → imoverclocked]

How is magnetic field history figured out?

[BWStearns → jjtheblunt]

Basalt on the ocean floor records the magnetic field of the earth from when it cooled. Since it radiates out from midoceanic rifts and the rate of its creation is known, we can use it as a diary of the magnetic field. Iirc we first figured it out during WW2 doing magnetic bathyometry to help ships navigate.

[CalRobert → jjtheblunt]

https://en.m.wikipedia.org/wiki/Remanence can get you started!

I did horribly in this lab session in college but it was still fun.

[ChrisMarshallNY → webwielder2]

There must have been a whole shitload of the little bugs. We've found so many of their fossils, that they are a commodity.

For each fossil, there's probably a thousand individuals that never got rocked.