PALAEOMAGNETIC RESULTS FROM MINOAN ASH DEPOSITS IN (RV VEMA) CORES V10-50 AND V10-58, SOUTH AEGEAN SEA

Abstract

Palaeomagnetic and anisotropy measurements were carried out on Minoan ash deposits obtained from the deep-sea cores, (V10-50 and V10-58), South Aegean Sea. Three distinct layers have been reported within the ash deposit in core (V10-50). Based primarily on grain-size differences, a link to three separate eruptive phases of Santorini has been suggested. Magnetic results were unable to resolve any differences between these layers which suggests that the eruption may have been a ‘single event’. Some magnetic parameters indicate that the final ignimbrite phase of the eruption of Santorini is most likely to have been responsible for the bulk of the deep-sea ash deposits, although a contribution from the first phase (phreatomagmatic and/or Plinian air-fall) cannot be excluded. Anisotropy of magnetic susceptibility measurements indicate a primary sedimentary fabric

and quiet depositional conditions for V10-50 ash sediment. A more disturbed petrofabric is observed for V10-58 suggesting, bottom current activity and/or slumping. The mean palaeomagnetic inclination calculated from appropriate V10-50 results is:- 60.2° ± 4.3° (corrected for anisotropy and geographical location differences of sites). This is statistically identical to values obtained for burnt mud brick from destruction sites in eastern Crete but different to the mean palaeomagnetic inclination obtained for central Cretan sites. A comparison with the secular variation (inclination) data for the Balkan region and for Greece, suggests that the eruption/s of Santorini occurred in the period between ~1540 and 1500 BC.