Fig. 3
(Redrawn, including relationships for curve fits, from Liu et al. (2007))
Coercivity variations and their influence on S-ratio and HIRM. aS-ratio (Eq. 1) and b HIRM versus coercivity of remanence (Bcr), where the S-ratio decreases with increasing coercivity and HIRM increases with increasing coercivity because more IRM is acquired above 300 mT as coercivity hardens. Such coercivity changes represent compositional differences in the analysed high-coercivity minerals, which can be assessed with c the L-ratio. Constant L-ratio values indicate consistent magnetic properties of the high-coercivity component, and changing values represent variable coercivity. Open circles represent synthetic Al-substituted hematites and solid circles represent Al-substituted goethites