Abstract

Icebergs plough through unconsolidated lake/sea sediments gouging out kilometre long grooves, 100s of metres wide and tens of metres deep. Although the surface morphology of iceberg scours is well-documented, little is known about what scours look like in stratigraphic section, particularly where surface characteristics are absent (e.g. through decay or burial). This investigation establishes a definitive suite of diagnostic criteria for identifying iceberg scours in clays by macroscopically and microscopically (2D thin sections) examining sediment deformation below iceberg scours in former Glacial Lake Agassiz, Manitoba, Canada. This suite of structures is unlike those found in subglacial tills and mass-wasting deposits. This research will be particularly valuable in palaeoenvironmental reconstruction and in predicting glacial dynamics. In addition, it may eventually aid structural engineering on polar shelves, which could be of great value to oil and gas companies.