The Internal Structure and Ice Crystallography of Seasonal Frost Mounds

Abstract The crystal character of the ice core within frost blisters supports the hypothesis that groundwater injection into residual zones of the active layer followed by rapid freezing is the primary growth mechanism for these features. The ice core is characterized by an upper zone of relatively...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Pollard, W. H., French, H. M.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1985
Subjects:
Online Access:http://dx.doi.org/10.1017/s0022143000006407
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000006407
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Summary:Abstract The crystal character of the ice core within frost blisters supports the hypothesis that groundwater injection into residual zones of the active layer followed by rapid freezing is the primary growth mechanism for these features. The ice core is characterized by an upper zone of relatively small randomly arranged equigranular ice crystals which change with increasing depth to columnar anhedral crystals, commonly exceeding 200 mm in length, and with crystal diameters ranging between 25 and 35 mm. Petrofabric analyses show that the c -axis orientations are normal to crystal elongations, with crystal growth along the basal plane in an a -axis direction. These observations eliminate ice segregation as a possible growth mechanism, thereby distinguishing seasonal frost mounds from palsas.