SOILS, HYDROLOGY AND MID-HOLOCENE SETTLEMENT PATTERNS IN THE CENTRAL KÖRÖS BASIN, EASTERN HUNGARY

The Körös Regional Archaeology Project focuses on a change from tell-based nucleated settlements to a more dispersed settlement pattern after the Neolithic / Copper Age transition (circa 6500 yr BP). In conjunction with this project, I am examining the regional terrain, soils and pre-canalization stream system to ascertain whether environmental factors (particularly the frequency and duration of seasonal wetness) may have influenced the changing settlement pattern.

The Körös Basin of eastern Hungary has undergone 150 m of sedimentation in the last 720 Ka at Vésztö. Sedimentation has been concentrated in glacial phases when eolian and alluvial sediment inputs were enhanced. Numerous sets of weakly expressed meander scars and levees imply that channel avulsion was a dominant mechanism of drainage adjustment during at least the latter phase of basin aggradation. Sediment inputs during the Holocene appear to be minimal. Most of the lower areas in this extremely low relief (1-2 m) landscape are mantled by pedogenically-problematic meadow clay soils which are characterized by 40 to 100 cm thick, black, dense, generally featureless silty clay A horizons above strongly-mottled weakly-developed silty clay loam subsoils. Vertic mixing of these smectite-rich soils has blurred any stratigraphic clues and hence the age and relative contributions of alluvial and colluvial sediment remain in question.

Cores of the highly sinuous Sebes Körös paleo channel and floodplain deposits near the Vésztö Magor tell site (A_d=4300 km²) revealed a very small pre-canalization channel (2.5-3 m deep and 25-30 m wide) that had meandered slowly (mean channel migration of 1 m per 20-40 years) at this location for at least the last 8500 years. In this low gradient landscape (1 m per 10 km), the sluggish Sebes Körös lacked the hydrologic capacity to significantly influence landscape hydrology. Thus the spring wetness of this subhumid basin, that likely impacted Neolithic and Copper Age settlement patterns, came principally from standing water due to low soil conductivity and exceedingly flat terrain. Soil and hydrologic data collected to date do not suggest marked mid-Holocene changes in regional hydrology.