Statistical analysis of geomagnetic reversal data and the precision of potassium-argon dating

TLDR

The study introduces a statistical method to determine the ages of geomagnetic polarity epoch boundaries by analyzing rock magnetic polarity as a function of potassium‑argon ages. The method simultaneously estimates the precision of potassium‑argon dating and applies the analysis to rock samples to infer boundary ages. The analysis yields a 3.6 % dating precision for ~2.5 m.y.

Abstract

A new statistical method has been developed for analyzing the magnetic polarity of rocks as a function of their potassium-argon ages for the purpose of determining the ages of the boundaries between geomagnetic polarity epochs. The analysis also yields an estimate of the precision of the potassium-argon dating. A value of 3.6% is found by this analysis for the dating precision of rocks about 2.5 m.y. old, which is in agreement with an independent estimate of the precision of the dating obtained from an analysis of analytical errors. The following are the best statistical estimates of the ages of the boundaries between geomagnetic polarity epochs: Gilbert-Gauss boundary, 3.36 m.y.; Gauss-Matuyama boundary, 2.5 m.y.; Matuyama-Brunhes boundary, 0.70 m.y. The duration of polarity events is estimated to vary from 0.07 to 0.16 m.y., and the best estimate of the time required for the earth's field to undergo a complete change in polarity is 4600 years.