Geochemical analysis of overbank sediments in Adventdalen and Ny-Ålesund

Sampling and analysis of overbank sediments is an efficient method for regional geochemical mapping, either for environmental studies or for prospecting of mineral resources. Ottesen et al, has previously used this method at Svalbard for a regional survey of a limited number of inorganic elements. Due to improved methods of analysis the last decades (e.g. inductively coupled plasma ? mass spectrometry, ICP-MS) it is now possible to analyze the samples for a much broader range of elements with far lower detection limits. Testing of overbank sediments is an efficient and discussed method. Rivers with variable water discharge experience flood, which in Norway is mainly during spring with melting of snow and ice. The water and materials in the river channel will then be transported into floodplains, where the material will accumulate with every flood. A vertical section through the accumulated deposits represents the sedimentation throughout the years. The upper layers represents recent time, while the lower layers represents further back in time. By comparing the layers you can find out the difference in mineral composition in each flood. Newer sediment layers tends to have higher pollution and the older will represent the natural environment. Testing of overbank sediments is also an interesting method because you can map a big area with only a few tests.