Premium
Origin and characteristics of massive ground ice on Herschel Island (western Canadian Arctic) as revealed by stable water isotope and Hydrochemical signatures
Author(s) -
Fritz Michael,
Wetterich Sebastian,
Meyer Hanno,
Schirrmeister Lutz,
Lantuit Hugues,
Pollard Wayne H.
Publication year - 2011
Publication title -
permafrost and periglacial processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 76
eISSN - 1099-1530
pISSN - 1045-6740
DOI - 10.1002/ppp.714
Subject(s) - geology , meltwater , ice sheet , sea ice , oceanography , arctic ice pack , ice stream , ice shelf , glacial period , antarctic sea ice , arctic , glacier , geomorphology , cryosphere
Herschel Island in the southern Beaufort Sea is a push moraine at the northwestern‐most limit of the Laurentide Ice Sheet. Stable water isotope (δ 18 O, δD) and hydrochemical studies were applied to two tabular massive ground ice bodies to unravel their genetic origin. Buried glacier ice or basal regelation ice was encountered beneath an ice‐rich diamicton with strong glaciotectonic deformation structures. The massive ice isotopic composition was highly depleted in heavy isotopes (mean δ 18 O: −33‰; mean δD: −258‰), suggesting full‐glacial conditions during ice formation. Other massive ice of unknown origin with a very large δ 18 O range (from −39 to −21‰) was found adjacent to large, striated boulders. A clear freezing slope was present with progressive depletion in heavy isotopes towards the centre of the ice body. Fractionation must have taken place during closed‐system freezing, possibly of a glacial meltwater pond. Both massive ground ice bodies exhibited a mixed ion composition suggestive of terrestrial waters with a marine influence. Hydrochemical signatures resemble the Herschel Island sediments that are derived from near‐shore marine deposits upthrust by the Laurentide ice. A prolonged contact between water feeding the ice bodies and the surrounding sediment is therefore inferred. Copyright © 2011 John Wiley & Sons, Ltd.