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Relict periglacial features east of waterton‐glacier parks, alberta and montana, and their palaeoclimatic significance
Author(s) -
Karlstrom Eric T.
Publication year - 1990
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.3430010303
Subject(s) - geology , outwash plain , glacial period , geomorphology , glacier , quaternary , moraine , rock glacier , solifluction , paleontology
Stratigraphy and inferred genesis of relict periglacial features east of Waterton‐Glacier Parks provide information on the magnitude of Quaternary climate changes. Periglacial wedges, involutions, patterned ground and soil wedges are locally preserved in pre‐Wisconsinan outwash/ alluvium and till on a series of erosion surfaces east of the Lewis Range mountain front and in Wisconsinan outwash near Cutbank, Montana. Formation of periglacial wedges required development of perennially frozen ground and mean annual temperatures at least about 10°C below those of today. All the observed relict periglacial features occur within about 20 km of Wisconsinan glacier margins. Strongly weathered, 2+ m thick, pre‐Illinoian palaeosols, also preserved locally on the erosion surfaces, are truncated and/or completely stripped in the areas most affected by cryoturbation. Hence, most of the periglacial features postdate the palaeosols. Stratigraphic and geomorphic relations suggest that the periglacial features formed during at least three glacial/periglacial episodes, probably including the Wisconsinan, Illinoian and a pre‐Illinoian glaciation.