THE NATURE AND ORIGIN OF GROUND ICE IN THE HERSCHEL ISLAND AREA, YUKON TERRITORY.
The nature of ground ice on Herschel Island reflects the geornorphic processes and thexmal conditions of the late Quaternary period. Field studies carried out from 1986 to 1988 investigated cryostratigraphic characteristics of ice-rich sections exljosed in retrogressive thaw slumps and coastal bluff...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.560.6324 http://pubs.aina.ucalgary.ca/cpc/cpc5-23.pdf |
| Summary: | The nature of ground ice on Herschel Island reflects the geornorphic processes and thexmal conditions of the late Quaternary period. Field studies carried out from 1986 to 1988 investigated cryostratigraphic characteristics of ice-rich sections exljosed in retrogressive thaw slumps and coastal bluffs in the Herschel Island area of the Yukon Coastal Plain. Sediment and ice ~amples were analysed for moisture content, grain size, and ice petrography. Ground ice constitutes up to 60-70 % of the upper 10-12 m of permafrost. Melting of massive ground ice and ice-rich materials have produced numerous large retrogressive thaw slumps. The petrographic characteristics of 5 types of massive ground ice were determined, including: ice-wedge ice. buried snowbank ice, injection ice, segregated and glacier ice. Ice of glacial origin is tentatively identified in areas of glacially-thrust marine sediments. The presence of very large active and inactive ice wedges, together with ice-wedge casts, multi-stage and syngenetic ice wedges in deformed sediinents indicate a very long period of cold post-glacial conditions interrupted by one or two periods of deep thaw. The deformed nature of these materials reflect the glacial ice-thrust processes which formed the island and complicate cryostratigraphic interpretation. Resume La nature de la glace de sol dans l'ile Herschel traduit les conditions thermiques et les processus g6omorphologiques de la fin du Quaternaire. Des Ctudes de terrain sur les caractCristiques cryostrati-graphiques de coupes riches en glace, dCgagCes dans des glissements de terrain et des falaises littorales. ont |
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