Baltic Ice Lake levels and a LiDAR/DEM-based estimate of the glacio-isostatic uplift gradient of the Salpausselkä zone, SE Finland

• Published in: Bulletin of the Geological Society of Finland Vol. 91; no. 1; pp. 119 - 137
• Main Authors: Lunkka, Juha Pekka, Nikarmaa, Tiina, Putkinen, Niko
• Format: Journal Article
• Language: English
• Published: Geological Society of Finland 01.01.2019
• Subjects: digital elevation model (dem); equidistant diagram (distance diagram); glaciofluvial delta; glacioisostatic uplift gradient; highest shoreline; lidar; palaeo-isobase; salpausselkä end moraines; southern finland; younger dryas stadial
• ISSN: 0367-5211; 1799-4632
• DOI: 10.17741/bgsf/91.1.005

Glaciofluvial ice-contact deltas were mapped and altitudes of the highest shorelines defined in the eastern arc of the Salpausselkä zone, southern Finland, using Light Detection and Ranging (LiDAR)-based digital elevation models and GIS tools. Mapping of deltas and the highest shorelines in the Salpausselkä zone were undertaken in order to calculate and define the glacio-isostatic uplift palaeo-isobases, uplift gradients and equidistant diagrams (distance diagrams) for the Salpausselkä zone. The results indicate that the glacio-isostatic uplift palaeo-isobases were orientated NE-SW (50°–230°) and the uplift gradients for both the First and the Second Salpausselkä in the eastern arc, are virtually the same, namely 0.6 mkm-1. This suggests that both Salpausselkä ridge complexes, which were originally laid down in front of the Finnish Lake District Ice Lobe (FLDIL) in relatively shallow water, were deposited within a short time period during the Late Weichselian Younger Dryas Stadial. The results also suggest that the Baltic Ice Lake water level regressed 7.5 metres from Baltic Ice Lake level B I to level B III as the ice retreated in its eastern arc from the First to the Second Salpausselkä.