Sedimentary and tectonic development of a high‐arctic, thrust‐moraine complex: Comfortlessbreen, Svalbard

Abstract

The glaciotectonic processes that have shaped the morphology and structural geology of the Comfortlessbreen thrust‐moraine complex are shown to be largely proglacial in origin, with the development of low‐angle thrusts, nappe‐like structures and folds. The propagation of the deformation has extended into the glacier foreland. A style of deformation called the ‘englacial deformation zone’ explains the incorporation of subglacial debris into the ice by thrusting and subsequent deposition of thrust sheets is inherited from the ice structures. A model for thrust‐moraine development and its possible chronology at Comfortlessbreen emphasizes the role played by glaciomarine sediment in facilitating deformation and also the role of thrusting, rathcr than pushing, in moraine formation. The importance of sediment type in controlling the overall development of the moraine is emphasized and a comparison to illustrate this control is made with neighbouring Uvẽrsbreen.