Geoarchaeological Case Studies in the Bakırçay Valley
Schneider, Steffen Hermann Friedrich · Universitätsbibliothek der FU Berlin Hochschulschriftenstelle u. Dokumentenserver · 2014
The Bakırçay valley is one of the large east-west trending graben landscapes in western Anatolia. The ruins of Pergamon (modern Bergama), situated at the northern fringe of the valley, are the most outstanding example of the numerous archaeological sites within this old cultural landscape. The Bakırçay valley has not yet been studied from the paleogeographical and geoarchaeological points of view. This study aims at the reconstruction of the middle to late Holocene landscape development in the western hinterland of Pergamon and thus of the western Bakırçay valley. Furthermore, interactions between landscape changes, human settlement and land use activity are investigated. Geomorphological, sedimentological, and geophysical investigations are coupled with archaeological research with close cooperation between the DFG (German Research Foundation) cluster of Excellence Topoi, the Pergamon excavation of the German Archaeological Institute and the DFG Priority Programme 1209 ‘The Hellenistic polis as a living space’. Three select landscape compartments of the western Bakırçay valley were investigated in detailed case studies: (i) The surroundings of the ancient polis of Atarneus, a hilltop settlement near the Aegean coast. (ii) The valley of the Geyikli, the westernmost perennial tributary of the Bakırçay. (iii) The environs of the archaeological site ‘Teut114’ with buried wall structures of unknown function in the central Bakırçay valley. These case studies revealed approximately four millennia of the landscape and settlement history of the Bakırçay valley. The landscape was remarkably stable during this period. (i) The sedimentary plains surrounding the settlement hill of Atarneus were aggraded by braided and meandering rivers. Colluviation and alluvial fan deposition occurred at the foot-slopes. Sedimentation totalled approximately 5 to 7 m, showing evidence of a “drowning” of the landscape in terrestrial sediments. In general, the depositional system did not change. This striking resistance to the changing settlement and land use intensity is an effect of the modification of the slopes through terracing that countervailed erosion and likewise increased the buffering capacity of sediment storage on the slopes. There is no evidence that landscape deterioration contributed to the abandonment of Atarneus. Rather, socio-economic factors were crucial for the rise and fall. (ii) The Lower Geyikli Valley was inhabited by a braided river with a highly dynamic depositional system. Sedimentation totalled approximately 4 to 6 m. Only in recent times, gravel mining has led to a deformation of the valley floor, and the Geyikli’s fluvial terrace has become inactive. (iii) In the middle Holocene, the site ‘Teut114’ was situated on a depositional piedmont plain, which was protected from the annual Bakırçay floods. Over the past two millennia, the Bakırçay flood plain was continuously aggraded, and the site became prone to flooding.