DETAILED MAGNETIC SURVEY UNMASKS PREHISTORIC ARCHAEOLOGICAL SITES IN ISRAEL

Abstract

Prehistoric archaeological sites consist significant part of the discovered archaeological objects in Israel. Among different geophysical methods applied at the Prehistoric sites in Israel, detailed magnetic investigations play the most important role. The rapid and reliable investigations allow consistently estimate the possible archaeological significance of the area under study. Interpretation of magnetic surveys in Israel is complicated by several factors, the most significant from which is a strong oblique magnetization of the Earth’s magnetic field (about 45). The variable structure of the upper part of the geological section often does not allow to determine the level of the normal magnetic field within the studied sites. Noise caused by iron objects and electric power lines sometimes reaches high values. Uneven topography also disturbs the effect from the archaeological targets. The complicated conditions of the survey require advanced methods for delineation of buried objects, their quantitative interpretation and 3-D modeling. We present here results of detailed magnetic investigations at four most typical objects: Eynan site of Natufian period (northern Israel), Nahal Zehora site of Pottery Neolithic period (northern Israel), Kissufim Road of Chalcolitic period (southern Israel) and multilevel Proto-Historic site Tel Megiddo (northern Israel). Introduction Prehistoric archaeological sites consist about 12-15% of the total number of discovered archaeological objects in Israel (Kenyon, 1979; Reich, 1992; personal communications with Israeli archaeologists). We can suggest that the total number of Prehistoric sites in Israel (known and expected objects) may reach 2,500-3,000 units. Geophysical examination of ancient sites is now recognized as obligatory element of archaeological investigations (Dalan and Banerjee, 1996; Bates and Bates, 2000; Eppelbaum et al., 2001a, Von der Osten-Woldenburg et al., 2002, etc.). Geophysical surveys provide a ground plan of cultural remains before excavations or may be even used instead of excavations. Such investigations should help estimate the possible archaeological significance of the area under study. Detailed magnetic investigations are widely used for studying of Prehistoric sites in the world (Gibson, 1986; Frederick and Abbott, 1992; Kozhevnikov et al., 2001; Crew, 2002; Von der Osten-Woldenburg et al., 2002; Sarris et al., 2004, Krivanek, 2005, etc.) and in Israel (Itkis and Eppelbaum, 1998; Eppelbaum and Itkis, 2000; Eppelbaum et al., 2000b; Itkis et al., 2003; Eppelbaum and Itkis, 2005). Rapid (first results may be obtained during a few hours − several days) and reliable interpretation of magnetic data could provide protection of archaeological remains from unpremeditated destruction. Cost of these investigations usually in many tens of times less that the total worth of archaeological investigations. At the same time, highprecision magnetic investigations at archaeological sites in Israel are affected by a lot of different factors (Eppelbaum and Khesin, 2001). The most significant disturbing feature is a strong oblique magnetization of the Earth’s magnetic field (43-46). The multi-layered and variable structure of the upper part of the geological section often does not allow to calculate the level of the normal magnetic field within the studied sites. Noise caused by industrial iron and iron-containing objects (sometimes –electromagnetic objects) may reach high values. Rugged relief also disturbs the effect from the buried archaeological objects. The complicated conditions of the survey require modern