This week ended the 2004 campaign for our geomorphologists. Over large areas around the city, the original topography is nearly totally transformed by field terraces, so it goes without saying that the geomorphologists (Etienne Paulissen, Véronique De Laet, and Rebekkah Merriman, KULeuven) pay a lot of attention to these features. Field terraces transform the original slope into steps, composed of stonewalls separated by a less sloping fields. The stones for building the terrace walls are mainly taken locally, especially in the zone with deposits from mass movements. The main aim of this study is to find decisive arguments to conclude that during the Roman period, the Sagalassians already constructed stone-walled field terraces for agricultural purposes. Our starting point is that terrace construction dates from all periods. Even today new terraces are constructed or smaller terraces are enlarged to form one single field. From many observations, we suggest that terraces have been built preferentially on slope deposits derived from the limestone substrate and from the ophiolithic "mélange" (mostly mass movement deposits). Field terraces on flysch deposits are rare and recent, based on the field dimensions and wall construction. It is therefore likely that in the past there were no fields in areas with a flysch substrate. They could have been used for grazing or wood production, as still is mainly the case today.

The amount of recent colluvia on the terraces is very restricted. Soil is taken away from the upper part of the field and is deposited behind the lower terrace wall. This means that each terrace consists of two different surfaces: a new surface postdating the terrace construction in the upper part, while behind the lower terrace wall the original soil is buried. Correlation of the original soil surface in different fields will give us data about the original topography before terrace construction started and about the amount of soil moved during construction. Ceramics and radiocarbon ages of charcoal in the original soil and in the fill will give us, respectively, a minimum age for the soil and a maximum age of the fill. As an example, we can mention a result from last year. East of Sagalassos, behind a terrace wall under a fill, we discovered an ancient field with an agricultural soil containing ceramics, bones, and charcoals. According to the calibrated radiocarbon dates, the soil dates from A.D. 115 (+/-115) to 875 (+/-105). Chemical elements (phosphorous, copper, lead, manganese, and potassium) in this soil suggest pollution from manuring and industrial activities in the city.