GEOSCAN Search Results: Fastlink


TitleAccelerating Thermokarst Transforms Ice-Cored Terrain Triggering a Downstream Cascade to the Ocean
AuthorRudy, A C A; Lamoureux, S F; Kokelj, S V; Smith, I R; England, J H
SourceGeophysical Research Letters vol. 44, issue 21, 2017 p. 11080-11087,
Alt SeriesNatural Resources Canada, Contribution Series 20170086
PublisherAmerican Geophysical Union
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthwest Territories
NTS88B; 88C
AreaBanks Island; Johnson Point Watershed; Prince of Wales Strait
Lat/Long WENS-119.0000 -118.0000 73.1667 72.6667
Subjectssurficial geology/geomorphology; climate effects; climate, arctic; permafrost; ice lenses; ground ice; overburden; moraines; thermokarst; sediment transport; fluvial systems; fluvial transport
Illustrationslocation maps; photographs; graphs; satellite imagery; histograms
ProgramWestern Arctic Sverdrup Basin, GEM2: Geo-mapping for Energy and Minerals
Released2017 11 11
AbstractRecent climate warming has activated the melt-out of relict massive ice in permafrost-preserved moraines throughout the western Canadian Arctic. This ice that has persisted since the last glaciation, buried beneath as little as 1 m of overburden, is now undergoing accelerated permafrost degradation and thermokarst. Here we document recent and intensifying thermokarst activity on eastern Banks Island that has increased the fluvial transport of sediments and solutes to the ocean. Isotopic evidence demonstrates that a major contribution to discharge is melt of relict ground ice, resulting in a significant hydrological input from thermokarst augmenting summer runoff. Accelerated thermokarst is transforming the landscape and the summer hydrological regime and altering the timing of terrestrial to marine and lacustrine transfers over significant areas of the western Canadian Arctic. The intensity of the landscape changes demonstrates that regions of cold, continuous permafrost are undergoing irreversible alteration, unprecedented since deglaciation (~13 cal kyr B.P.).
Summary(Plain Language Summary, not published)
Pervasive buried glacial ice underlying >12 000 km2 of eastern Banks and adjacent Victoria islands has exhibited a sudden (post-2011) and exponential increase in the rate of thermokarst-related (melting of ice-rich terrain) land failures (retrogressive thaw slides). Perhaps the most active area documented on Earth for this style of permafrost melt, it signals a threshold landscape change brought on by changes in temperature and precipitation. Occurring within an area of kimberlite (diamond) drift exploration, it is recognized that the extent of landsliding has significant implications for understanding the source of potential kimberlite indicator minerals (KIMs). New sediment inputs into regional streams are potentially liberating KIMs that have different potential glacial sources (englacial vs subglacial) and transport trajectories.