> Hypotheses have also advanced toward linking reversals to mass extinctions.[47] Many such arguments were based on an apparent periodicity in the rate of reversals, but more careful analyses show that the reversal record is not periodic.[17] It may be, however, that the ends of superchrons have caused vigorous convection leading to widespread volcanism, and that the subsequent airborne ash caused extinctions.[48] (https://en.wikipedia.org/wiki/Geomagnetic_reversal)