Abstract Details

ID: 543
Title: Is there anything other than human-induced dust in the last millennium air?
Content:

Natural and anthropogenic dust sources may be difficult to differentiate (e.g. fires arising from either natural or human ignition sources, or soil erosion due to natural processes or agriculture), especially during the last millennium, where anthropogenic forcing factors may be superimposed to natural ones. Soil dust is mainly derived from the erosion of the upper continental crust and soil regolith, which forms the major interface between the geosphere and the biosphere. It has been recently proposed that atmospheric soil dust (ASD) fluctuations during the last millennium may not be solely related to human activities, because increases in crop pollen do not always show a relationship with increases of ASD. However, complications in correlating events arise from the difficulty of obtaining very high-resolution chronologies. We review here the ASD and pollen records from five European sites (Belgium, Poland, Sweden and the UK). ASD is obtained using various techniques such as counting quartz grains or deriving dust content from Ti concentrations. We also apply a novel radiocarbon calibration technique (BACON) allowing for the development of grey scale proxies (i.e. integrating the age probability in the proxy vs. age graph), which, compared with proxy vs. depth graphs, substantially changes the vision of abrupt events. Our results suggest that in most studied cases there is a decoupling between a long-term human impact and abrupt dust peaks, suggesting that these peaks may originate from enhanced storminess/windiness during specific time windows (e.g. the Little Ice Age).

Session: 5 Mineral Dust: a product and agent of Quaternary climate change
Authors: François De Vleeschouwer
Rixt de Jong
Gaël Le Roux
Paul Hughes
Presenter:François De Vleeschouwer
Type: poster