After a week of surveying the characteristics and relative age of the multiple mass movements on the mountain slopes, the geomorphological team (Etienne Paulissen, Véronique Delaet, and Rebekkah Merriman, all KULeuven) moved on to coring of colluvial/alluvial deposits in the valley system of the Catal Oluk Deresi, an affluent of the Aglasun Cayi, just west of Sagalassos. This affluent drains the town of Sagalassos and the mountain slopes to the west. We want to know the type, the amount and--very important--the age of the sediments that have been delivered by the different sub-basins within the Catal Oluk Deresi river system. Coring in these sediments, which contain a lot of rock fragments, is hard labor, but is often successful if you have:
- suitable coring equipment such as heavy percussion devices!
- enthusiastic and strong workers!
- and enough spare parts to replace broken or even lost pieces!
The results of this week's coring campaign can be summarized as follows: thick (>11 m) accumulations of fine sediments, all derived from the ophiolitic mélange, occur in the valley bottom upstream from Alexanders' Hill. This accumulation is anterior to the occupation of the town and doesn't contain any ceramics or charcoal. It is covered with a thin unit of limestone fragments and clays derived from the adjacent limestone slopes. Few ceramics occur on the surface here. The picture is totally different immediately downstream from Alexanders' Hill after the confluence with one of the two subsystems draining Sagalassos. Here the older deposits are lacking, but there is a new, relatively thin (1-2 m on average) accumulation of dark brown clays containing limestone cobbles. It is surprising to observe in all cores in this area small rolled ceramics and charcoal, which strongly suggests that these relatively thin deposits are Roman or post-Roman in age. The second subsystem draining the eastern part of Sagalassos is clearly erosive as the bedrock is nearly always at the surface. Collegial deposits are very restricted and not worth coring, except for a few gardens near a farm.
From these data we suggest that the total amount of sediments delivered from the site of Sagalassos to the main river was restricted and that human impact in this mountainous environment close to an important town didn't cause severe soil degradation and subsequent erosion. Were the Sagalassians better soil conservationists than other people in the Roman Empire? Or do we exaggerate human impact on soil degradation during classical times in many regions? Those questions should be solved in future terrain campaigns.