Geomorphic Reconstruction of Paleolake Levels in Arctic Fennoscandia

Abstract

This thesis investigates the presence and extent of a former paleolake in the transboundary region of Sweden, Finland, and Norway in northern Fennoscandia (68.864°N, 21.064°E). The aim is to identify geomorphological evidence in the landscape that may indicate the presence and extent of a previous ice-dammed lake during the late stages of deglaciation associated with the retreat of the Scandinavian Ice Sheet (SIS). Emphasis is placed on identifying deltaic and coastal features, as well as periglacial and subglacial features that may record past lake levels and basin development, glacial retreat, and ice-dammed areas. The study area runs along the Könkämä River, where palsa mires exist in the sporadic permafrost zone. This project uses remote sensing data layers and a geographic information system (GIS) to identify lake-indicative landform elements. Digital terrain models (DTMs) derived from high-resolution airborne Light Detection and Ranging (LiDAR) data and satellite imagery are the primary sources for mapping and analyzing landforms across the study area. These spatial observations are compared with existing geodata in the region and with other documented examples from similar studies in previously glaciated regions. The results from 231 mapped shorelines suggest the existence of a previously unknown paleolake at 507 meters above sea level (m.a.s.l.), contributing to a broader understanding of deglaciation processes in northern Fennoscandia. The results also highlight the role of geospatial techniques in identifying and interpreting large-scale paleo-hydrological features in formerly glaciated environments.