image/svg+xml129 X/2/2019 INTERDISCIPLINARIA ARCHAEOLOGICA NATURAL SCIENCES IN ARCHAEOLOGY homepage: http://www.iansa.eu 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) Freek Braadbaart a , Anaya Sarpaki b* , Harry Veld c , Bertil van Os d a Faculty of Archaeology, Leiden University, Einsteinweg 2, 2333CC Leiden, Netherlands b Independent scholar, 137 Tsikalarion Rd., Tsikalaria, Souda,73200 Crete, Greece c Deltares, Daltonlaan 600, 3584 BK Utrecht, Netherlands d Cultural Heritage Agency of the Netherlands, Conservation of Built Monuments and Archaeology, Smallepad 5, 3811 MG Amersfoort, Netherlands 1. Introduction The Bronze Age settlement of Akrotiri is situated on the southern coast of Thera, a volcanic island, belonging to the Cyclades, in the Aegean Sea (Greece). From an archaeological point of view the Bronze Age is in this region divided into three major periods i.e. Early Cycladic (EC) (3000–2100 BC), Middle Cycladic (MC) (2100–1600 BC) and Late Cycladic (LC) (1600–1100 BC). The huge Plinian (Minoan) eruption buried and at the same time preserved the settlement by layers of hot tephra ejected from the volcano. The date of the eruption has been much debated in the literature and has led to a dispute between the approaches of conventional archaeology and scientifc archaeology. Based on recent information a late seventeenth BC date seems now to be accepted (see among others: Manning et al. , 2014, p.1176; MacGillivray, 2014). The ejected tephra layers are divided into a precursory phase followed by four main phases of the eruption each with its characteristic composition (Figure 1). Only the precursory and the two following phases are present in Akrotiri due to their erosion. Many studies deal with these phenomena and the reader is referred to these studies and the references cited therein (Bond and Sparks, 1976; Heiken and McCoy, 1984; Druitt et al., 1989; Heiken et al., 1990; Sparks and Wilson, 1990; Friedrich et al., 1990; McCoy and Heiken, 2000; Friedrich and Heinemeier, 2009; Friedrich, 2013).Systematic archaeological excavations at Akrotiri started in 1967 by Marinatos and are continued to this day by Christos Doumas. The data shows that already since, at least, the Late Volume X ● Issue 2/2019 ● Pages 129–141 *Corresponding author. E-mail: a.sarpaki@gmail.com ARTICLE INFO Article history: Received: 24 th July 2018Accepted: 16 th December 2019 DOI: http://dx.doi.org/ 10.24916/iansa.2019.2.3 Key words: Thera – AkrotiriCycladic PeriodBronze Agecharcoal analyses refectance analyses burning temperaturetephra ABSTRACT The Bronze Age settlement site of Akrotiri, situated on the island of Thera in the Aegean Sea (Greece), developed during a period of over 1500 years into a fourishing 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 fres lighted by the occupants of the city i.e. charred organic materials (COM) and ash. The volcanological part of the investigations studied the infuence 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 refectance 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 fres 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.
image/svg+xmlIANSA 2019 ● X/2 ● 129–141 Freek Braadbaart , Anaya Sarpaki, Harry Veld, Bertil van Os: 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) 130 Neolithic, and continuously in the EC and MC periods the settlement was occupied and gradually developed into a fourishing city at the end of the MC (Doumas, 2012). At the time of the eruption and its destruction, in the beginning of the LCI period, the city was inhabited by a very afuent society that built multi-story buildings with magnifcent wall-paintings, drainage systems, paved street and even toilets.The archaeological excavations showed that during all the periods of occupation charred organic material (COM) was present and recovered from the settlements. During the EC and MC periods the heat necessary to char the organic material was generated by fres induced by the occupants for heating, cooking or other pyro-technological purposes, such as metal-working. The fres and heating continued in the LC I period before the city was buried by the volcanic hot tephra of the Minoan eruption. However, around 50 years preceding the Minoan eruption seismic activities in the form of earthquakes had ravaged the city several times in the MC period causing severe destructions to the buildings (Palyvou, 2015; McCoy and Heiken, 2000). As a result, the then present streets and ground foors were covered with a layer of debris consisting of building material: the volcanic destructing level (VDL), consisting of building material, with a thickness in the order of 1 to 2 metres. (Figure 2), and the city underwent major architectural changes as they