Description, distribution, and paleoclimatic significance of relict periglacial features east of Waterton-Glacier parks, Alberta and Montana

Conference · Thu Apr 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5018771

Karlstrom, E T ^[1]

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1. California State Univ., Stanislaus, Turlock, CA (United States). Geography Dept.

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. Ice-wedge casts, observed at six sites within 8 km of the Wisconsinan Laurentide glacier boundary, are 80 to 400 cm wide at the top and 95 to 240 cm deep. Host gravels are commonly foliated against wedge margins. Formation of these wedges required development of perennially frozen ground and mean annual temperatures at least 10 degrees C below those of today (5 degrees C). Soil wedges and tongues, 40 to 70 cm wide at the top and up to 55 cm deep, are developed in loess overlying the outwash/alluvial gravels, and in till and lacustrine deposits. They also occur at five sites within 8 km of the Wisconsinan Laurentide glacier boundary. Involutions and predominantly vertically-oriented gravels occur at eight more widely distributed sites without ice-wedge casts. Strongly weathered, 2+ m thick, pre-Illinoian paleosols, 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 paleosols. 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.

• OSTI ID: 5018771
• Report Number(s): CONF-9305259--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ALBERTA
ALLUVIAL DEPOSITS
CANADA
CENOZOIC ERA
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
GEOMORPHOLOGY
GLACIERS
MONTANA
MORAINES
NORTH AMERICA
PALEOCLIMATOLOGY
PALEONTOLOGY
PETROLOGY
PLEISTOCENE EPOCH
QUATERNARY PERIOD
STRATIGRAPHY
USA