Source Region Geochemistry From Unmixing Downstream Sedimentary Elemental Compositions

The geochemistry of river sediments is routinely used to obtain information about geologic and environmental processes occurring upstream. For example, downstream samples are constrain chemical weathering physical erosion rates upstream, as well the locations mineral deposits or contaminant sources. Previous work has shown that, by assuming conservative mixing, can be reliably predicted given a known source region geochemistry. In this study, we tackle inverse problem “unmix” composition produce geochemical maps drainage basins (i.e., regions). scheme tested in case study rivers draining Cairngorms, UK. elemental ?m fraction 67 gathered from beds channels invert for concentrations major trace elements A smoothed solved using Nelder-Mead optimization algorithm. Predictions assessed comparing spatial distribution 22 different affinities (e.g., Be, Li, Mg, Ca, Rb, U, V) independent survey data. approach makes reliable predictions element concentration first order sediments. We suggest could novel means generate baselines across within channels.