During a geomagnetic reversal the geomagnetic field becomes weaker, and stays weak for thousands of years during the transition to the opposite polarity.
32.
Evidence for these " geomagnetic reversals " can be found in basalts, sediment cores taken from the ocean floors, and seafloor magnetic anomalies.
33.
:The last swing of the VGP from the southern hemisphere to the northern hemisphere in the Brunhes-Matuyama geomagnetic reversal took only 38 yr.
34.
A polarity excursion, which can be either global or local, is a shorter-lived version of a geomagnetic reversal and does not significantly affect 14C production.
35.
In any case, there was no scientific evidence linking a solar maximum to a geomagnetic reversal, which is driven by forces entirely within the Earth.
36.
The magnetic susceptibility profiles of these sediments have been dated using magnetostratigraphy, which identifies geomagnetic reversals, and correlated with climate indicators such as oxygen isotope stages.
37.
Most scientific estimates, however, say that geomagnetic reversals take between 1, 000 and 10, 000 years to complete, and do not start on any particular date.
38.
The age of Western Pacific seafloor has been interpreted from seafloor magnetic anomalies correlated to the geomagnetic reversal timescale and confirmed by Ocean Drilling Program scientific drilling.
39.
The effect should further not be confused with the effect known as geomagnetic reversal that describes the repeated proven reversal of the magnetic field of the Earth.
40.
:Geomagnetic reversal # Future of the present field suggests that it's not likely to happen soon, but the whole thing's too poorly understood to predict with any certainty.
