TY - JOUR
T1 - Mapping seabed geomorphology in the Inner Hebrides, Scotland; Bathymetric records of ice streaming and retreat
AU - Dove, Dayton
AU - Finlayson, Andrew
AU - Bradwell, Tom
AU - Arosio, Riccardo
AU - Howe, John
PY - 2014/5/1
Y1 - 2014/5/1
N2 - Approximately 7,000 km² of new bathymetry have been stitched
together with onshore airborne radar data, both gridded at 5m
resolution, to map and describe the submarine glacial landscape of the
Inner Hebrides sector of the former British-Irish Ice Sheet (BIIS). As
part of the MAREMAP Project (http://www.maremap.ac.uk), and to build on
previous work (Howe et al., 2012), we are using recently acquired swath
bathymetry data, collected primarily by the UKHO Civil Hydrography
Programme, to characterise the geomorphology, sea-bed sediments, and
bedrock geology of the Inner Hebrides region. Mapping has revealed an
extensive array of well-preserved glacigenic landforms on the seabed
associated with key stages of ice flow and retreat of the BIIS following
the Last Glacial Maximum. On multiple submarine rock platforms and
within overdeepened troughs, diverse assemblages of glacially
streamlined landforms are present, forming a geomorphic continuum
between rock drumlins and mega-flutes. Superimposed streamlined bedforms
indicate different phases of fast flow at the ice sheet bed, and the
convergence of flow sets suggest that ice sheet flow was organised into
faster flowing topographically controlled corridors. Across the region,
the streamlined landforms occur within a geographically controlled zone,
semi-independent of the underlying geology. This is consistent with the
onset zone of the Hebrides Ice Stream, as previously postulated (Howe et
al., 2012). Submarine moraine ridges are observed widely across the
survey area: within sea lochs, atop rock platforms and superimposed on
glacially streamlined bedforms, as well as pinned to topographic highs
(i.e. islands). Some retreat patterns reveal clear glacial recession
towards respective catchments, while others are more ambiguous and are
the focus of ongoing work. The bathymetry data notably reveal more
geomorphic evidence of glaciation than adjacent land records, thus
providing the opportunity to reassess onshore mapping where clear
offshore examples may provide insights into poorly understood
terrestrial geological and geomorphological features. And importantly,
these new data provide the opportunity to greatly improve offshore
geology maps of the region, which are in increasing demand by
governmental, commercial, and conservation groups.
AB - Approximately 7,000 km² of new bathymetry have been stitched
together with onshore airborne radar data, both gridded at 5m
resolution, to map and describe the submarine glacial landscape of the
Inner Hebrides sector of the former British-Irish Ice Sheet (BIIS). As
part of the MAREMAP Project (http://www.maremap.ac.uk), and to build on
previous work (Howe et al., 2012), we are using recently acquired swath
bathymetry data, collected primarily by the UKHO Civil Hydrography
Programme, to characterise the geomorphology, sea-bed sediments, and
bedrock geology of the Inner Hebrides region. Mapping has revealed an
extensive array of well-preserved glacigenic landforms on the seabed
associated with key stages of ice flow and retreat of the BIIS following
the Last Glacial Maximum. On multiple submarine rock platforms and
within overdeepened troughs, diverse assemblages of glacially
streamlined landforms are present, forming a geomorphic continuum
between rock drumlins and mega-flutes. Superimposed streamlined bedforms
indicate different phases of fast flow at the ice sheet bed, and the
convergence of flow sets suggest that ice sheet flow was organised into
faster flowing topographically controlled corridors. Across the region,
the streamlined landforms occur within a geographically controlled zone,
semi-independent of the underlying geology. This is consistent with the
onset zone of the Hebrides Ice Stream, as previously postulated (Howe et
al., 2012). Submarine moraine ridges are observed widely across the
survey area: within sea lochs, atop rock platforms and superimposed on
glacially streamlined bedforms, as well as pinned to topographic highs
(i.e. islands). Some retreat patterns reveal clear glacial recession
towards respective catchments, while others are more ambiguous and are
the focus of ongoing work. The bathymetry data notably reveal more
geomorphic evidence of glaciation than adjacent land records, thus
providing the opportunity to reassess onshore mapping where clear
offshore examples may provide insights into poorly understood
terrestrial geological and geomorphological features. And importantly,
these new data provide the opportunity to greatly improve offshore
geology maps of the region, which are in increasing demand by
governmental, commercial, and conservation groups.
M3 - Article
VL - 16
SP - 4212
JO - EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria, id.4212
JF - EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria, id.4212
ER -