KONYA BASIN PALAEOENVIRONMENT RESEARCH (KOPAL) PROGRAMME
by Neil Roberts
A successful geoarchaeological survey of the Çumra district took place between September 4 and 22 1995 under the auspices of the Turkish Ministry of Culture, and with the financial support of the National Geographic Society. We are indebted to both of these, to the British Institute of Archaeology at Ankara, to Loughborough and Ankara Universities, and to our representative from Konya Museum, Necip Cay. The field season involved the following personnel: Dr Hakan Yigitbasioglu, Dr Romola Parish, Dr David Twigg, Peter Boyer and John Tibby.
The prime objective of the 1995 season was to undertake systematic geoarchaeological and geomorphological survey of the area north of Çumra (Konya vilayet) in order to establish a three-dimensional lithostratigraphic sequence for the Çarsamba alluvial fan. Holocene alluviation on the fan has partially or completely buried many archaeological sites; for example, coring at Çatalhöyük in 1994 indicated 2-3 metres of post-Neolithic alluvium.
Methods. Geoarchaeological investigations were carried out at 12 archaeological sites. At each site the depth of post-occupation burial by alluvium was obtained by coring near the edge of the mound. The coring continued below cultural levels in order to establish the nature and thickness of the underlying 'natural' alluvial and lacustrine deposits. The periods of human occupation at ten of the mounds has been established by archaeological surveys undertaken by Dr Trevor Watkins and Dr Douglas Baird in 1993 and 1995; in addition, Çatalhöyük is of course being excavated. Further stratigraphic information was obtained from irrigation ditch sections which were cleaned, recorded and sampled.
Coring was carried out by Cobra vibro-corer. Topographic data were obtained by surveying using a high precision Leica system 200 GPS (Global Positioning System) and associated SKI and LISCAD software, operated by Dr David Twigg. This proved highly successful in providing horizontal and vertical data over a range of 10x20 km, with a precision of +/- 1 cm. It was also used to create a topographic map of the mound at Çatalhöyük West.
Results. The cores and sections from archaeological sites indicated, in general, greater depth of alluvial burial for earlier sites and for sites in the southern part of the study area; that is, higher up the Çarsamba fan. For example, at Dolay höyük near the northeastern edge of the alluvial fan, the combined depth of cultural and alluvial sediments was only 230 cm; whereas upstream at Torundede höyük they were 645 cm thick, including 320 cm of alluvium beneath the mound.
Two principal alluvial units of Holocene age seem to be present on the Çarsamba fan north of Çumra; an older dark grey 'backswamp' clay, locally apparently organic, and a younger red-brown clay-silt. The backswamp clay is cut into by a river palaeochannel which was sampled in 1994 and which has produced OSL dates between 7125 and 3324 years BP. Probable Early Chalcolithic sherds from the lower part of a backswamp clay fill of another channel-like feature south of Çatalhöyük would appear to confirm that this lower alluvial unit is early Holocene in age. The red-brown upper alluvium overlies both palaeochannels, and also appeared to seal a Late Chalcolithic pit/ditch feature at Kuslu höyük II; in other words, it is mid-to-late Holocene in age. The mound at Kuslu höyük II was cut into by an irrigation section, and the resulting stratigraphy was studied in conjunction with Dr Baird's survey team. This showed that, in this area at least, the underlying marl surface was irregular rather than sub-horizontal. Variations in the tkickness of alluvium may therefore occur at local as well as regional scales.
Cores were taken between the East and West mounds at Çatalhöyük in order to see if sediments of the Çarsamba river are present, particularly for the period contemporary with the site occupation. Close to the East mound, probable in situ Neolithic layers were encountered beneath fluvial sands and gravels, at a depth of 226-318 cm below modern ground surface. At a second core site between the mounds, organic peat and silts (310-464 cm) accumulated in what may have been an abandoned river channel; this also contained cultural debris, probably discarded into the former channel.
Conclusion. The sediment cores and samples obtained during the 1995 field season fulfilled our planned objectives, and will provide the basis for reconstructing geomorphological changes on the Çarsamba alluvial fan during the last 10,000 years. It is planned to complete data collection on the fan in 1996, mainly around Çumra itself, in conjunction with Dr Baird's archaeological survey team. When complete, they will help to explain the pattern of archaeological site distribution and, in particular, biasses due to site 'loss' through alluvial burial. It is also intended to continue work at Çatalhöyük, focussing on the relationship between on-site mound-forming processes and off-site alluviation, and on evidence for cultural impact on 'fields' in the immediate vicinity of the site.