Evolution of Andfjorden Trough-Mouth Fan, Norwegian Sea: buried glacigenic debris-flows and mega-scale glacial lineations

Abstract

Evolution of the Andfjorden Trough-Mouth Fan (TMF) on the Troms continental margin, northern Norway (Fig. 1a), is reconstructed using 2D- and 3D-seismic data (Rydningen et al. 2016). A tripartite Quaternary evolution of the TMF is found. Phase one is characterized by distal glacimarine/glacifluvial sedimentation. Glaciers reached the shelf break at least once during this period, identified by possible glacigenic debris-flows (GDFs) in the lower part of the succession. In phase two, repeated shelf-break terminating ice streams are inferred. A final phase is characterized by fast-flowing ice streams traversing the shelf, evidenced by buried mega-scale glacial lineations (MSGLs) in the upper sedimentary succession. Fig. 1. ( a ) Location of study area (red box; map from GEBCO_08). White line indicates the position of the seismic profile in (b). ( b ) Composite seismic line covering the shelf-slope sedimentary system. The inferred Quaternary glacigenic sediments are divided into three seismic units – S2 (the oldest), S3 and S4 – separated by erosional unconformities (T1, T2 and T3). T4 marks the base of Andfjorden palaeo-canyon which is partly filled with pre-Quaternary …