59. The peat profile of Rue des Boîteux–Rue d’Argent (BR295), Senne valley, Brussels (Belgium)

Abstract

The site of Rue des Boîteux–Rue d’Argent (BR295) (coordinates 50° 51’ N; 4° 21’ E, 17 m above sea level [a.s.l.]) is situated in the actual town centre of Brussels, at the foot of a steep slope leading from the alluvial plain of the Senne River to the Brabantian plateau.Mean annual temperature in Brussels is 10.4 °C. Mean temperature is 3.2 °C for January and 18.4 °C for July. Mean precipitation reaches 848 mm (KMI s.d.). The actual soil moisture regime of the region is Udic (soil moisture is sufficient throughout the year to meet plant requirements [USDA 1999: 97]). The soil temperature regime is Mesic. This implies that the mean annual soil temperature is 8 °C or higher and lower than 15 °C, and the difference between mean summer and mean winter soil temperatures is more than 6 °C (USDA 1999: 112). During a rescue excavation in 2014, a thick peat deposit was discovered. The top of the peat was affected by human activity and gradually transformed into an urban Dark Earth. Locally, modern construction works truncated the peat deposit. The peat deposit with total thickness of c. 2 m was sampled at three profiles by overlapping monolith blocks. The blocks were correlated stratigraphically based on their lithology (Table I) and the chronology was subsequently confirmed with absolute dates (Table II) so that a composite profile was obtained. Samples for pollen analysis (with volume 3 cm2) were taken at each 2.5 cm. Dating