Identifying the Controlling Factors on Variable Glacial Modification of Bedrock Dominated Areas in Kongsfjorden, Svalbard

Abstract

This thesis aims to better understand the variability of glacial erosion along glacial troughs located in high latitude settings, through a case study of Kongsfjorden, Svalbard. The research question of this thesis is to identify the controlling factors on variable glacial modification of the bedrock dominated areas in Kongsfjorden. Fieldwork was conducted to analyze bedrock structures and glacio-erosional landforms of outcrops on islands distributed within Kongsfjorden. These findings were compared with regional patterns using available Digital Elevation Model’s (DEMs) of the surface, subglacial and bathymetrical topography. The identified factors controlling variable glacial modification included variation in bedrock mechanical properties, linear fracture zones, and changes in glacio-erosional processes. The bedrock mechanical properties show that the rocks located at Lovénøyane, around the center part of the fjord, have a lower erosion resistance compared to the rocks located at the nunataks, at the innermost part of the fjord. The assessment of the linear fracture zones show that the main structures of the area are N-S and NW-SE oriented. These structures relate with overdeepended linear valleys within the fjord and are suggested to have formed by differential glacial erosion of the weak brecciated rocks within the fracture zones. The elongation ratio of landforms show that the more streamlined and elongated landforms are distributed towards the outer fjord. The implications of the findings suggest a modest amount of glacial erosion took place at the Lovénøyane ridge relative to the outer fjord. This study suggests that the ice dynamical behavior at the Lovénøyane ridge was lower relative to the overdeepened channel down-ice towards the outer fjord. This change in paleo-ice flow dynamics could represent a zone of acceleration of the Kongsfjorden paleo-ice stream tributary.