Mitsuo Hoshino, Nagoya University (Japan)
Tsuyoshi Tanaka, Nagoya University (Japan)
Toshio Nakamura, Nagoya University (Japan)
Hidekazu Yoshida, Nagoya University (Japan)
Takeshi Saito, Meijo University (Japan)
Kazuhiro Tsukada, Nagoya University (Japan)
Yusuke Katsurada, Nagoya University (Japan)
The Syria-Japan multidisciplinary archaeological joint research entitled ?gFormation of Tribal Communities in the Bishri Region, Middle Euphrates?h has started in 2007 spring. Since then, the archaeological team has been concentrating on excavation of the sites which are located on the lowermost river terrace of the Euphrates, ca. 50 km ESE of Raqqa city. Many lines of archaeological evidence indicate that the sites can be dated back to the Early Bronze Age. In parallel with that excavation, our geological team has carrying out detailed field survey in and around the excavation sites in order to understand the environmental changes of the area since prehistoric times by using geological, geochemical, geochronological and remote sensing methods.
Basement rocks are well exposed at the northern edge of the Bishri Mountains and consist mainly of gypsum with subordinate amounts of tuff, sandstone and siltstone. The depositional ages of the rocks were estimated to be Neogene by previous palaeontological studies. Their bedding planes exhibit almost horizontal structure which signifies relatively static sedimentary environment at the time. In the inner part of the Bishri Mountains, however, Palaeogene sedimentary rocks predominate and include archaeologically interesting asphalt deposits and flint rocks of high quality. In places, basaltic lava-flows and pyroclastics cover the basement rocks. Three specimens of basaltic rock yielded K-Ar ages of 1.38 ?} 0.08 Ma B.P., 2.60 ?} 0.08 Ma B.P. and 2.72 ?} 0.09 Ma B.P., respectively.
Five levels of river terrace, I, II, III, IV and V in descending order and a flood plain of the Euphrates are recognizable. Two excavation sites, Tell Ghanem al-Ali and Tell Hammadin are located on the lowermost terrace V. The flood plain includes modern channels, oxbow lakes, banks and marshes. River terraces and surrounding area have been changed their topography owing to a long-time utilization by human activity. Actually, the terrace V is used as irrigated cropland and small villages, and terrace IV and higher terraces are used as towns. Detailed geographic and sedimentological analyses of the river terraces are also performed.
Four charcoal specimens from Tell Ghanem al-Ali sediment, one from Tell Hammadin sediment, two from terrace V sediment and one from terrace III sediment were collected for 14C dating. Although the analyses for these specimens are in progress, one specimen from Tell Hammadin gives an age around 4.0 Ka B.P. that coincides with Early to Middle Bronze Age estimated by archaeological evidence.