Die spätglaziale und holozäne Beckenfüllung des Moores »Turbastall« bei Schlins (Vorarlberg, Österreich)

The sediment fill of the small Turbastall basin near Schlins (Vorarlberg, Austria) was investigated. The basin was formed in Flysch bedrock by glacial erosion during the last – Würmian – glaciation. Once the glacier had disappeared, clastic and organic sediments were deposited. Six sediment types were identified in a total of 13 shallow borings and in a few local outcrops: subglacial till, lacustrine clay, calcareous gyttja, peat, clayey colluvium and silty colluvium. A 3D-model of the distribution of these sediment types was constructed in a geographical information system. »Ghost wells« – virtual borings with a sediment sequence based on expert knowledge – were added to the database, to compensate for the limited number of true data points and the uneven distribution over the present-day peat bog. The resulting 3D-model is considered a realistic approximation, and it depicts the finescale variation in sediment fill within the basin. Comparison of the fill with published records of nearby similar small basins (e. g. van Mourik et al. 2013) indicates that local conditions determine the origin of the sediment succession against the background of late-glacial to post-glacial climate change. Evaluation of published 10Be age datings of erratic boulders in the area around
the town of Feldkirch (de Graaff et al. 2023) suggests that the Turbastall basin became free of ice at about 16000 years ago, i. e. deposition started around this time. Carrying valuable information on the local and regional landscape evolution, Turbastall is a potential geoconservation site.