A palaeointensity study has been carried out on a Pliocene sequence of 20 consecutive lava
flows where previous directional results seem to reflect anomalous behaviour of the Earth’s
magnetic field (EMF), which can be explained by a polarity transition record or non-averaged
palaeosecular variation or both. Here, we perform a total of 55 palaeointensity determinations
using the original Thellier–Thellier (TT) method and 100 with the IZZI method.We assess the
performance of our selection criteria using a set of strict threshold values applied to a set of
test data whose TRMs were acquired in known fields. Absolute palaeointensity determinations
that passed our selection criteria were obtained on four specimens with the TT method and on
41 specimens with the IZZI method. Application of reliability criteria at a site level yielded
palaeointensity results in 8 of 20 studied lava flows. We obtained median values of VADM
between 28.9 and 45.6 ZAm2 for the reverse polarity lower Apnia section, while the normal
polarity upper section displayed a single value of 54.6 ZAm2. The low palaeointensity values
before a transitional direction lava flow and the higher value after it, suggest the common
behaviour at the start of a polarity reversal and the recovery after it. However, an isolated
record of a stable EMF, where the intensity is lower than the current for the same location
(83.7 ZAm2), cannot be discarded. Consequently, this interpretation would support a weak
time-averaged field.
