Subglacial drainage patterns of Devon Island, Canada: detailed comparison of rivers and subglacial meltwater channels

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dc.contributor.author Grau Galofre, Anna
dc.contributor.author Jellinek, Mark
dc.contributor.author Osinski, Gordon, R.
dc.contributor.author Zanetti, Michael
dc.contributor.author Kukko, Antero
dc.date.accessioned 2018-10-23T15:22:13Z
dc.date.available 2018-10-23T15:22:13Z
dc.date.issued 2018
dc.identifier.issn 1994-0416
dc.identifier.uri http://hdl.handle.net/10138/252788
dc.description.abstract Subglacial meltwater channels (N-channels) are attributed to erosion by meltwater in subglacial conduits. They exert a major control on meltwater accumulation at the base of ice sheets, serving as drainage pathways and modifying ice flow rates. The study of exposed relict subglacial channels offers a unique opportunity to characterize the geomorphologic fingerprint of subglacial erosion as well as study the structure and characteristics of ice sheet drainage systems. In this study we present detailed field and remote sensing observations of exposed subglacial meltwater channels in excellent preservation state on Devon Island (Canadian Arctic Archipelago). We characterize channel cross section, longitudinal profiles, and network morphologies and establish the spatial extent and distinctive characteristics of subglacial drainage systems. We use field-based GPS measurements of subglacial channel longitudinal profiles, along with stereo imagery-derived digital surface models (DSMs), and novel kinematic portable lidar data to establish a detailed characterization of subglacial channels in our field study area, including their distinction from rivers and other meltwater drainage systems. Subglacial channels typically cluster in groups of ˜ 10 channels and are oriented perpendicular to active or former ice margins. Although their overall direction generally follows topographic gradients, channels can be oblique to topographic gradients and have undulating longitudinal profiles. We also observe that the width of first-order tributaries is 1 to 2 orders of magnitude larger than in Devon Island river systems and approximately constant. Furthermore, our findings are consistent with theoretical expectations drawn from analyses of flow driven by gradients in effective water pressure related to variations in ice thickness. Our field and remote sensing observations represent the first high-resolution study of the subglacial geomorphology of the high Arctic, and provide quantitative and qualitative descriptions of subglacial channels that revisit well-established field identification guidelines. Distinguishing subglacial channels in topographic data is critical for understanding the emergence, geometry, and extent of channelized meltwater systems and their role in ice sheet drainage. The final aim of this study is to facilitate the identification of subglacial channel networks throughout the globe by using remote sensing techniques, which will improve the detection of these systems and help to build understanding of the underlying mechanics of subglacial channelized drainage. fi
dc.language.iso en fi
dc.publisher Copernicus Publications fi
dc.relation.ispartofseries The Cryosphere fi
dc.title Subglacial drainage patterns of Devon Island, Canada: detailed comparison of rivers and subglacial meltwater channels fi
dc.type Artikkeli lehdessä fi
dc.format.volume 12 fi
dc.format.issue 4 fi

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