During the second week of the geomorphological survey, Etienne Paulissen and his collaborators Veronique De Laet, who grew muscles handling the Ramguts drill, and Koen Dossche, continued trying to solve the puzzle of the colluviation/alluviation history in the basin of the Aglasun Cay, to which Sagalassos belongs. The geomorphological settings in this basin are very complex. In most parts of the valley, the lateral sediment influx related to different types of geomorphological processes from the mountain slopes dominate over the longitudinal processes related to the river system. Forms and fluvial deposits related to the Aglasun Cay are very limited in some areas.
During earlier surveys, large alluvial fans composed of fine sediments had been cored. They don't contain datable materials, but there are archaeological remains on their surface. We believe that these fans were build up before the last Ice Age, during it, or both. In one area, we found intercalations of colluvial and organic deposits within thick loose travertine deposits to a depth of at least ten m. The geochronological framework of these deposits is based on ten radiocarbon dates. The oldest dated layer, at a depth of nine m, has a calibrated age of around 6550 B.C. The palynology and sedimentology of these deposits are studied by M. Vermoere and S. Six.
This week we cored in two areas, the first area is in the upstream end of the valley of the Aglasun Cay, west of the village of Basköy. The top layer, about two m thick, consists of colluvial and in some areas of organic deposits. Beneath this layer is a unit of loose coarse sands and gravels, at least three m thick. The core transect strongly suggest coarse alluvial fan deposits deposited in fluvial beds. We found no datable material and no travertine deposits here, so the source for the travertines in the valley remains unknown.
The second area is in the mouth of the subbasin draining Sagalassos and in the immediate environs, where the two most important secondary valleys meet (at the first S-curve of the road from Aglasun towards Sagalassos, where the Pinarbasi Spring is). At this point, there is an obvious change in the morphology and the landscape of the valley: the upstream part has many agricultural terraces occupying the entire valley bottom, while the downstream part is still eroding. The maximal thickness of the colluvial deposits that were cored on these agricultural terraces is about two m. The top part of these deposits were reworked by man during the construction of these terraces. In one of the cores, coarse river bed sediments occur between one and two m. They contain huge amounts of well rounded fragments of ceramics (tula fragments), indicating that the entire deposits are of historical age. We assume that in the natural river system the riverbed was in the bedrock and that most of the sediments eroded from this subbasin, were transported downvalley. Colluviation in these valley bottoms started when man transformed the valley bottom into terraced fields.