Using Preisach Theory to Evaluate Chemical Remanent Magnetization and Its Behavior During Thellier‐Thellier‐Coe Paleointensity Experiments

Abstract

AbstractThe behavior of grain‐growth chemical remanent magnetizations (gCRM) are investigated for different coercivity and magnetostatic‐interaction‐field distributions and acquisition conditions using a thermally activated Preisach model for assemblages of interacting single‐domain grains. A new growth‐rate dependent equation was derived, from which it was found that gCRM intensity is over 10% more sensitive to growth rate than previously modeled. We compare the gCRM results to the behavior of thermoremanences (TRM). gCRMs are two times more sensitive to changes in coercivity distribution, whereas TRMs are four times more sensitive to changes in magnetostatic interactions. The Thellier‐Thellier‐Coe paleointensity protocol was simulated in Preisach space, and gCRMs were found to produce concave‐up Arai plots with pTRM checks which plot to the left of the Arai plot and positive partial‐TRM tail checks that increase with magnetostatic interactions. This often leads to the failure of selection criteria, but high‐temperature segments can pass the criteria for weakly interacting gCRMs; these estimates can underestimate the field by up to 66%.