The last Fennoscandian Ice Sheet

: a palaeo-glaciological reconstruction on theKola Peninsula and Russian Lapland

Abstract

The Late Weichselian (c. 40-10 ka) Fennoscandian Ice Sheet (FIS) has been a focus of research for over a century, and yet the pattern, style, and timing of glaciation remains uncertain on the Kola Peninsula and Russian Lapland, northwest Arctic Russia. Existing lower-resolution geomorphological data preclude an accurate reconstruction of ice dynamics in the region. Thus, the aim of this thesis is to produce a palaeo-glaciological reconstruction of Late Weichselian glaciation on the Kola Peninsula and Russian Lapland based on newlyacquired geomorphological data and existing numerical dates. Systematic and comprehensive geomorphological mapping using high-resolution remotely-sensed data identifies 245,997 glacial landforms, greatly expanding the known distribution of glacial landforms in the region; these landforms are the primary components for a new palaeo-glaciological reconstruction of the ice sheet. Following the glacial inversion approach, the full population of landform data are summarised as discrete cartographic units – flowsets – and their spatial, temporal, and glaciodynamic information are extracted. Theresulting landform summaries are then used to reconstruct ice flow configuration histories and ice margin positions. This is the first glacial reconstruction of the Kola Peninsula and Russian Lapland to employ the entire glacial landform assemblage. This reconstruction is finally combined with a database of 209 numerical ages, compiled from the literature, to provide chronological constraint. The resulting time-slice reconstruction reveals a complex pattern of ice sheet advance and retreat across the Kola Peninsula and Russian Lapland between c. 29 and 11 ka at both an ice sheet- and local-scale. Four definite and three possible palaeo-ice streams in the region are likely to be a consequence and driver of major ice sheet configuration change during the Late Weichselian. A transient ice divide that existed c. 25-20 ka was replaced by ice flow from the main ice dispersal centre of the FIS during deglaciation. Deglaciation (c. 16-11 ka) was characterised by ice sheet thinning, with topography constraining ice flow around upland areas. Major standstills and/or readvances of the retreating ice margin, including a detailed Younger Dryas ice marginal zone (c. 12 ka) are also reconstructed. This reconstruction highlights the interplay between the last FIS and the wider Earth system, presents empirical data in a format that is ideal for testing and validating numerical ice sheet and climate models, and provides a framework for future field investigations of the FIS in the region.

Date of Award	Mar 2022
Original language	English
Awarding Institution	University of Brighton
Supervisor	Lorna Linch (Supervisor), Danni Pearce (Supervisor) & David Nash (Supervisor)