Holocene alluvial sediment storage in a small river catchment in the loess area of central Belgium

摘要: Abstract Soil erosion and sediment deposition widely affect landscape development, particularly in erosion-prone areas with loess-derived soils. Nevertheless, until now, few attempts were made to quantify soil losses storage over long (centennial or millennial) timescales. In this study, the Holocene alluvial a small river catchment (52 km2) of Belgian loess belt is estimated, preliminary budget for presented. valley Nethen River (c. 13 km long), detailed survey archive was conducted. Hand augerings percussion drillings along cross-valley transects at 12 locations catchment. AMS 14C dating peat samples provided temporal framework interpretation cores. Results show that thickness deposits 4 6 m, which corresponds total clastic mass ∼14 × 106 t stored bottom. Three units could be distinguished associated phases from 9600 2900 B.C., B.C. A.D. 1000 present. contrast older sediments (units 1 2), last year (unit 3) contain little organic matter. They are seldom intercalated layers, devoid tufa. Unit 3 reaches c. 2 m, thereby representing 50% plain. The mean sedimentation rate plain phase ∼26 t ha− 1 a− 1, about tenfold larger than rates calculated units. Sediment supply towards has therefore increased tremendously since Medieval times. These results obtained colluvial nearby dry within Nethen, where started early Iron Age already substantial during Roman Age. This means there time lag one millennium between onset high upstream area probably caused by change coupling (sediment connectivity) plateau, slopes, rivers. As proceeds, first zero-order valleys act as traps, only after these filled floodplains. illustrates eroded deposits, mainly located on footslopes bottoms. Another 29%