Magnetic enhancement; Floodplain sediments; Dating proxy; Pollution signals; Heavy metals; Radioisotope 137Cs

Twenty five floodplain sediment profiles from seven rivers in eastern Czech Republic and three in north west England were collected to examine the hypothesis that magnetic enhancement in recent sediments is predominantly of anthropogenic origin and that magnetic parameters can be used as a dating proxy reflecting changes in intensity of industry sources over time. Natural sources of magnetic enhancement were excluded and anthropogenic enhancement was identified as exhibiting elevated values of ?lf, ARM, SIRM, SIRM/? and S-ratios with low values of ?fd%. Magnetic spherules, typically formed through fossil fuel combustion processes, were observed by scanning electron microscopy. To assess the potential of magnetic parameters as a chronometer, the approach was compared with other dating techniques: concentrations of heavy metals and 137Cs. The profiles were divided to three groups according to their trends with depth in magnetic parameters, and the suitability of magnetic properties as a dating proxy.