Nína Aradóttir

This thesis describes the evidence of palaeo-ice streams in northeast Iceland. Ice streams within the Iceland Ice Sheet (IIS) had been previously proposed, but limited studies existed on their geomorphology. The aim of this study was to advance the understanding of the geomorphological imprint, configuration, and dynamics of palaeo-ice streams and their development during and following the Last Glacial Maximum by mapping glacial landforms and analyze their internal architecture. The research focuses on streamlined subglacial bedforms (SSBs; drumlins and mega-scale glacial lineations), crevasse-squeeze ridges (CSRs), and ribbed moraines; however, glaciofluvial and ice-marginal landforms, as well as hummocky terrain were also mapped. The distribution and orientation of SSBs reveal four flow-sets of cross-cutting palaeo-ice streams that shifted in time and space, along with ice divides. During the maximum glaciation, ice flow was towards the north, unconstrained by the topography, but became confined to the fjords and valleys as the ice sheet thinned. The CSRs and ribbed moraines indicate ice-stream shutdown following glacier readvances during the Late Glacial. The variance in landform morphology and distribution is used to reconstruct the configuration and dynamics of the ice streams. The results provide new insight into the dynamics of the IIS and palaeo-ice streams within it and are essential for constraining numerical modelling experiments of the ice sheet’s evolution. This research has implications for our understanding of modern and palaeo-ice sheet behaviour during deglaciation and under warming climate, and paves the way for further studies and reconstructions of palaeo-ice streams in Iceland.