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TitleMeltwater landform perspectives on subglacial hydrological processes: insights from high-resolution mapping in northern Canada
AuthorLivingstone, S; Lewington, E L M; Clark, C D; Storrar, R D; Sole, A J; McMartin, IORCID logo; Dewald, N; Ng, F; Vérité, J; Ravier, E
SourceGSA Connects 2021; Geological Society of America, Abstracts With Programs vol. 53, no. 6, 242-7, 2021 p. 1,
Alt SeriesNatural Resources Canada, Contribution Series 20210164
PublisherGeological Society of America
MeetingGSA Connects 2021: Geological Society of America Annual Meeting 2021; Portland, OR; US; October 10-13, 2021
Mediaon-line; digital; video
File formathtml; pdf
NTS55E; 55F; 55J; 55K; 55L; 55M; 55N; 55O; 55P; 56A; 56B; 56C; 56G; 65I
AreaChesterfield Inlet; Hudson Bay
Lat/Long WENS -97.0000 -88.0000 65.5000 61.2500
Subjectssurficial geology/geomorphology; hydrogeology; Science and Technology; Nature and Environment; glacial history; glaciation; deglaciation; ice sheets; ice margins; glacial landforms; eskers; moraines; moraine, de geer; paleodrainage; glacial erosion; glaciers; depositional history; bedforms; ArcticDEM; Hydrology; Digital elevation data; subglacial meltwater corridors; esker ridges; Phanerozoic; Cenozoic; Quaternary
ProgramGEM-GeoNorth: Geo-mapping for Energy and Minerals GEM Program Coordination
Released2021 10 01
AbstractThe configuration and evolution of meltwater drainage under ice sheets is a key control on ice flow, erosion, sedimentation and frontal ablation. Meltwater landforms allow the properties of meltwater drainage to be reconstructed, typically over centennial to millennial time-scales and spatially over 100s of km. They therefore have enormous potential for informing our understanding of modern day subglacial hydrological processes, which are difficult to observe directly. Recently, the availability of high resolution (2 m) digital elevation models (e.g. ArcticDEM) has facilitated the discovery and mapping of meltwater imprints at an unprecedented level of detail and scale.
This presentation summarises recent holistic mapping efforts, which reveal diverse meltwater traces forming an integrated network across northern Canada. Eskers are typically surrounded and joined by wider meltwater corridors (100s to 1000s m wide) that comprise both erosional and depositional forms (such as hummocks, ridges, murtoos), including subglacial bedforms (e.g. ribbed moraine tracts). We suggest that meltwater corridors formed by the exchange of water and sediment between a conduit (esker) or efficient core and the surrounding hydraulically-connected distributed drainage system (corridor) in response to variable melt inputs. The landform signature of meltwater corridors is likely influenced by different styles of drainage (e.g. from laterally constrained floods to distributed drainage) and coupling with the ice above. Eskers are interpreted to record a composite signature of ice marginal drainage. This interpretation is based on the close 1:1 association between beaded eskers (series of aligned sediment mounds) and De Geer moraine (i.e., each bead is associated with a corresponding ridge) in Keewatin, which suggests that they are quasi-annual ice-marginal deposits formed time-transgressively at the mouth of subglacial conduits during deglaciation.
Summary(Plain Language Summary, not published)
The distribution and nature of meltwater landforms developed under past ice sheets are used to reconstruct former subglacial drainage configuration. Recently, high-resolution digital elevation models have become available and facilitated the detailed mapping of meltwater imprints in northern Canada and informed our understanding of modern day subglacial hydrological processes, difficult to observe beneath active ice sheets. This invited keynote presentation summarizes work undertaken by university and government researchers from UK, France and Canada, on the mapping efforts that revealed a diverse yet integrated network of meltwater traces across Canada. The talk will be presented at the Geological Society of America (GSA) meeting in October 2021 as part of the Session on Glacial Hydrology: Processes Operating within, beneath, and along the Margins of Glaciers and Ice Sheets.

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