Anchor ice, seabed freezing, and sediment dynamics in shallow arctic seas

Journal of Geophysical Research-Oceans
By: , and 

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Abstract

Diving investigations confirm previous circumstantial evidence of seafloor freezing and anchor ice accretion during freeze-up storms in the Alaskan Beaufort Sea. These related bottom types were found to be continuous from shore to 2-m depth and spotty to 4.5-m depth. Spotty anchor ice occurred as pillow-shaped crystal aggregates on buried slabs of frozen sand surrounded by unfrozen sand. Considerations of required conditions for ice bonding and anchor ice growth allows regional extrapolation and suggests the possibility of anchor ice growth out to 20-m depth, the estimated maximum depth of supercooling during fall storms. Anchor ice and seabed freezing apparently do not develop during a calm freeze-up. Because of the abrupt growth of anchor ice during a freezing storm and its release soon after formation of a surface ice cover, this ice type has not been documented before. The concretelike nature of frozen bottom, where present, should prohibit sediment transport by any conceivable wave or current regime during the freezing storm. But elsewhere, particularly where the bonded crust is broken by grounded ice, anchor ice lifts coarse material off the bottom and incorporates it into the ice canopy, thereby leading to significant ice rafting of shallow shelf sediment and likely sediment loss to the deep sea.

Publication type Article
Publication Subtype Journal Article
Title Anchor ice, seabed freezing, and sediment dynamics in shallow arctic seas
Series title Journal of Geophysical Research-Oceans
DOI 10.1029/JC092iC13p14671
Volume 92
Issue C13
Year Published 1987
Language English
Publisher American Geophysical Union
Description 8 p.
First page 14671
Last page 14678
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