[ericd]

Huh, interesting. Do you know if anyone has looked at whether the rate of genetic mutations increases during those 10k year periods of weakened magnetic field? Seems like that would cause the magnetosphere to become less effective at deflecting cosmic radiation.

[njarboe]

Many people have looked into if these reversals can cause extinction events and they don't appear to. Determining a change in average mutation rates seems like something that would not be possible from the rock record. The last reversal was so long ago that DNA does not survive well enough to do a good study even if one had the right kind of samples to work with.

[ericd]

Yeah, makes sense. I was thinking that you could look for an uptick in biodiversity or something from the fossil record, but I'm sure it would be tricky to separate the reasons for that.