Palaeomagnetic analysis on pottery as indicator of the pyroclastic flow deposits temperature: new data and statistical interpretation from the Minoan eruption of Santorini, Greece

We present the results of palaeomagnetic analysis on Late Bronge Age pottery from Santorini
carried out in order to estimate the thermal effect of the Minoan eruption on the pre-Minoan
habitation level. A total of 170 specimens from 108 ceramic fragments have been studied. The
ceramics were collected from the surface of the pre-Minoan palaeosol at six different sites,
including also samples from the Akrotiri archaeological site. The deposition temperatures of
the first pyroclastic products have been estimated by the maximum overlap of the re-heating
temperature intervals given by the individual fragments at site level. A new statistical elaboration
of the temperature data has also been proposed, calculating at 95 per cent of probability
the re-heating temperatures at each site. The obtained results show that the precursor tephra
layer and the first pumice fall of the eruption were hot enough to re-heat the underlying ceramics
at temperatures 160–230 ◦C in the non-inhabited sites while the temperatures recorded
inside the Akrotiri village are slightly lower, varying from 130 to 200 ◦C. The decrease of
the temperatures registered in the human settlements suggests that there was some interaction
between the buildings and the pumice fallout deposits while probably the buildings debris layer
caused by the preceding and syn-eruption earthquakes has also contributed to the decrease of
the recorded re-heating temperatures.