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Geologic Publications for Mount Rainier

Comparing supraglacial and proglacial debris on Emmons Glacier, Mt. Rainier, Washington

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Author(s): Benjamin Lungberg

Category: POSTER
Document Type: Capstone Presentation
Publisher: Department of Geosciences, Pacific Lutheran University
Published Year: 2020
DOI Identifier:
ISBN Identifier:

Emmons Glacier, which is located on the Northeast flank of Mt. Rainier, Washington has an ablation zone and proglacial area that are covered in rock debris. In this study, hand sample field analysis, data synthesis, and analysis of aerial imagery were done to determine the origin of the debris in the supraglacial and proglacial areas. Rock samples analyzed along the surface of the glacier show a majority of angular clasts suggesting an origin of wasting, likely rockfalls. Rock samples from the proglacial zone show an overall rounded characteristic, meaning that the debris went through entrainment and tractional contact with the bed, likely through a subglacial fluvial system. Evidence of a large moulin and surface crevasses back up the theory of origin for the proglacial zone by being an avenue from which debris that has fallen onto the glacier can make its way into the entrainment process and on to the terminus of the glacier. A very large and complex proglacial stream system suggests a powerful subglacial fluvial environment capable of eroding the bed. High weathering of surface debris makes it likely that the surface cover is mainly from the 1963 Little Tahoma rockfall event, whereas, the lack of weathering on proglacial debris argues that newer material must be being added to the system from more recent rock falls or bed erosion.

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Suggested Citations:
In Text Citation:
Lungberg (2020) or (Lungberg, 2020)

References Citation:
Lungberg, B., 2020, Comparing supraglacial and proglacial debris on Emmons Glacier, Mt. Rainier, Washington: Capstone Presentation, Department of Geosciences, Pacific Lutheran University,