Micromorphology of diamicton affected by iceberg-keel scouring, Scoresby Sund, East Greenland
Quaternary Science Reviews
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Linch, L., & Dowdeswell, J. (2016). Micromorphology of diamicton affected by iceberg-keel scouring, Scoresby Sund, East Greenland. Quaternary Science Reviews, 152 169-196. https://doi.org/10.1016/j.quascirev.2016.09.013
Icebergs are important as agents of deposition and seafloor reworking on glacier-influenced continental margins. When the keel of an iceberg exceeds water depth it ploughs through soft sediments producing scours/ploughmarks that can be kilometres long, hundreds of metres wide and sometimes tens of metres deep. Because the influence of iceberg keels on sediment is a critical factor when offshore structures (e.g. pipelines, power cables) are installed, the surface morphology of iceberg scours on the seafloor is relatively well-documented. Less however, is known about sub-scour deformation below the seafloor. This is particularly true of iceberg scoured diamicton (poorly sorted sediment comprising a variety of particle sizes), which is present in many high-latitude fjords and continental shelves. The aim of this research is to examine directly (macroscopically and microscopically, with thin sections) the style and intensity of deformation caused by the scouring action of iceberg keels in diamicton offshore of East Greenland. Results show that a distinctive suite of deformation structures (individual structures and overprinted structural patterns) dominated by planar shear, sediment mixing and high porewater, and dropstones characterises iceberg scoured diamicton. In addition, diamicton from areas of high-intensity iceberg scouring tends to show a wider variety, higher frequency and distribution, more abundant and better-developed deformation structures than diamicton from areas of intermediate- and low-intensity iceberg scouring. Characterising the effects of iceberg scour in diamicton is important more widely to inform: i) reconstruction of the geometry and dynamics of former ice sheets; and ii) installation and protection of offshore engineering structures in diamicton where iceberg scouring presents a geohazard. The value of micromorphology is significant especially in the absence of macroscopic sediment exposures/outcrops where the study of cores is necessary instead.
iceberg scours, ploughmarks, gouges, micromorphology, diamicton, ice-rafted debris (IRD), Scoresby sund, East Greenland
This research was primarily funded by the University of Brighton's ‘Rising Stars Initiative’ and the ‘School of Environment and Technology Research Investment Fund’, with supplementary funds awarded by the Quaternary Research Association. The funding sources had no involvement in study design, in collection, analysis and interpretation of data, in the writing of the article and in the decision to submit the article for publication.
External DOI: https://doi.org/10.1016/j.quascirev.2016.09.013
This record's URL: https://www.repository.cam.ac.uk/handle/1810/261526
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Licence URL: http://creativecommons.org/licenses/by-nc-nd/4.0/