The application of acceptance criteria to results of Thellier palaeointensity experiments performed on samples with pseudo-single-domain-like characteristics

The results of a simulated Thellier palaeointensity experiment show that the low temperature portion of Arai plots produced by samples with pseudo-single-domain (PSD)-like hysteresis properties can produce significant inaccuracies despite passing conventional acceptance criteria. Furthermore, full Arai plots which fail these criteria can still produce reasonably accurate results. The evidence presented suggests that during a palaeointensity experiment: pTRM checks can fail despite no alteration occurring, pTRM tail checks are not reliable as indicators of MD-like behaviour, room temperature susceptibility monitoring is unreliable for detecting alteration, and that the minimum requirement for the f (fraction)-value should be increased from 0.15 to at least 0.5.