The Upper Pleistocene loess record at Harmignies/Belgium — high resolution terrestrial archive of climate forcing

The loess/palaeosol sequence in a section at Harmignies in Belgium is one of the most important Upper Pleistocene sites in Northwest Europe. An extensive luminescence dating study was carried out to get a reliable chronological framework and to understand the climate forcing in an area where continuous permafrost dominated during most of the last glaciations. Twenty-eight samples were investigated by infrared optically stimulated luminescence (IRSL) and thermoluminescence (TL) methods resulting in more than 100 luminescence age estimates. The dating results on colluvial sediments are in good agreement with landscape destabilisation phases during OIS 5. During the last glacial, four major periods of loess accumulation were likely to have occurred in Europe. At the Harmignies section, the oldest loess was deposited between 67,000 to 60,000 yr, the second one from 60,000 to 50,000 yr, the third one from 50,000 to 40,000 yr and the youngest loess accumulation period started most likely after the Heinrich 3 event and lasted until the Heinrich 2 event (25,000–20,000 yr). Two main periods of permafrost occurred at approximately 60,000 and 28,000 yr bp.