Variability in the physical, chemical and magnetic properties of reservoir sediments; implications for sediment source tracing

Analysis of lake and reservoir sediment cores has provided information on sediment yields and sources and on environmental and contamination histories. Although high density coring is often used to minimize the error in estimating sediment mass and calculating sediment yield, recent research on environmental reconstruction and sediment source tracing has often used a single or small number of sediment cores. The variability associated with sediment sorting by the water body and the control of sorting processes on geochemical and magnetic characteris­ tics are, therefore, largely ignored. Analysis of existing data sets for four lowland England reservoirs has been undertaken in order to compare downcore variability in sediment properties with spatial variations in the same properties at time synchronous levels within the sediment column. Results of this analysis suggests that the spatial variability is often higher than downcore variability. The implications of such variability for sediment source tracing and environmental reconstruction are discussed.