| Summary: | International audience In the present study, we examine the TL signature of quartz grains (40-50 microns) from loess accumulated during the Weichselian (MIS 2-4) and Saalian (MIS 6) glaciations in Northwestern Europe (Belgium, Netherlands, Germany, Northwestern France, Channel Islands). The quartz TL signature is used herein for characterizing the loess deposits and for tracking dust provenance. Six groups of loess with distinct quartz TL signatures have been identified. In parallel, a heavy mineral analysis of the same loess deposits has been performed; the green amphibole (GA) is used as an index mineral. The spatial and temporal variability of the quartz TL signature and GA content suggest multiple dust sources and temporal provenance changes. Furthermore, the same combined quartz TL signature and GA analyses were applied to potential source materials (alluvial and estuarine sediments from major river systems as the Seine, the Somme and the Rhine; glacial and proglacial sediments related to the Scandinavian ice sheet). Our results indicate that the Northwestern European loess derive from two major proximal sources, following dominantly northwesterly to westerly wind tracks: (1) the fluvial sediments from the braided alluvial plains and (2) the fluvio-marine material exposed on the emerged continental shelves of the English Channel and the southern North Sea Basin. By contrast, a distal glacial source from the outwash plains of the Scandinavian ice sheet seems to be excluded. Overall, the results of the present study suggest that the combined quartz TL signal and GA analyses are likely promising diagnostic methods to identify sources in loess studies.
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