Space/Science — HabitableZone

Space/Science » in reply to The dying Earth

It's polar wander paths you need to be looking for.
podrock — (archived)

The magnetic direction of the pole is often preserved in the geologic record, in all sorts of rock types. As in all things geologic, there are many variables. One can read the paleomagnetic direction of a rock using an oriented sample and a spinning magnetometer to pick apart the magnetic direction in various minerals through different tempratures (a lengthy and tedious process, trust me). Using a vast amount of published data, one can start to put it into context. Of course continents move, and that has to be taken into account. The magnetic pole changes all the time, flipp'n and a flopp'n. (it's causes may be related to linear vorticies in the mobile outer core!). The axis of rotation of the planet changes as well, but this is less well understood. Finding points of reference on a changing planet is difficult. Hot spots like Yellowstone and Hawaii have traditionally been used as reference points, but the nature of hotspots over time can be disputed (are mantle plumes stable over time?)

There is a lot of information out there about how the magnetic field has changed over time. Now compare what is known about those changes verses drastic climate change or mass extinctions. Do the statistics and see if there is a corellation. Do the modeling to see if there is causation.

I know there has been research done into the length of the day over itme, but I don't have any reference for ya. Try the journal "Precambrian Research".

Climate change certainly has many sources. The ultimate question is: "is it occuring?" From a geologist's perspective the answer is, "Yes, of course, duh." The next question is: "Is there something we can do about it?"

The answer might be the same as that found by our ancestors:

"Adapt."

Some incomplete Wiki Links as starting points :

Geomagnetic reversal

&

<a href="http://en.wikipedia.org/wiki/Pole_shift_theory>Pole Shift

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