Charred Organic Material, Heated by Anthropogenic Fires and Hot Volcanic Products from the Minoan Eruption, Excavated from the Bronze Age Site of Akrotiri on the Cycladic Island of Thera (Greece)

developed during a period of over 1500 years into a flourishing city. This process started from the Late
Neolithic through the Early and Middle Cycladic periods to the beginning of the Late Cycladic period
when at a date in the late seventeenth century BC the city was buried and at the same time preserved
by four phases of hot tephra released from the Minoan eruption. The investigations covering the
archaeological excavations showed the remains of the fuels used for the fires lighted by the occupants
of the city i.e. charred organic materials (COM) and ash. The volcanological part of the investigations
studied the influence of the heat generated by the hot tephra on the wooden construction material,
incorporated in the buildings, when they were covered and heated by the tephra. By measuring the
reflectance on the charred organic material, the temperatures at which they were heated in the past
were determined by applying the existing calibration curves. The results provided very interesting
information about the function of the fires and the type of fuel resource selected by the occupants.
The elemental analyses and the opal phytoliths from the ash provided additional information. The
emplacement temperatures measured for the various phases of the hot tephra ranged from 310–340 ºC
for phase one, from 370–410 ºC for phase two and is around 500 ºC for phase four. It is interesting to
note that the black charred material appeared not always to be charcoal.