Crossover plots: A useful method for plotting SIRM data in paleomagnetism

Abstract

The effective grain-size of magnetic minerals, and therefore domain type, controls the saturation isothermal remanent magnetization acquisition and subsequent demagnetization response and can be used to create 'crossover' plots for paleomagnetic specimens, where %SIRM is plotted as a function of the field applied, using a logarithmic scale. This paper presents templates of such plots for magnetite, pyrrhotite, hematite and goethite, onto which sample data can be plotted for conventional paleomagnetic specimens to characterize their magnetic mineralogy and effective grain-size.