Paleointensity and Reversal Frequency of the Geomagnetic Field

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

Tauxe EAR-0003395 Paleomagnetic data tell us that the geomagnetic field changes polarity yet the causes and controls of this astonishing behavior remain a mystery. Furthermore, the frequency with which the field reverses has changed dramatically through time and has been steadily increasing from zero reversals in a 51 million year time interval in the Cretaceous (the Cretaceous Normal Superchron, or CNS) to about four per million in the more recent past. Why the field stopped reversing and why it started again is unknown. Was the geomagnetic field simply too strong to reverse? To address this issue, we require estimates of the average field strength for the recent past and the CNS. Despite major gains in paleointensity research, the average field intensities during these intervals is poorly constrained. Under this grant, the investigators will endeavor to improve the estimate of average paleointensity for the early Brunhes and for the CNS using basaltic glass samples from the Hawaii Drill Core and the Troodos Ophiolite, respectively.