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Bedload component of glacially discharged sediment: Insights from the Matanuska Glacier, Alaska

Geology

By:
, , , , , , and
DOI: 10.1130/0091-7613(2003)031<0007:BCOGDS>2.0.CO;2

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Abstract

The flux of glacially derived bedload and the proportions of the suspended and bedload components carried by proglacial streams are highly debated. Published data indicate a large range-from <30% to >75%-in the bedload percentage of the total load. Two "vents," where supercooled subglacial meltwater and sediment are discharged, were sampled over the course of an entire melt season in order to quantify the flux of glacially delivered bedload at the Matanuska Glacier, Alaska. The bedload component contributed by these vents, for the one melt season monitored, is negligible. Furthermore, the bedload fluxes appear to be strongly supply limited, as shown by the poorly correlated discharge, bedload-flux magnitude, and grain-size caliber. Thus, in this case, any attempt to employ a predictive quantitative expression for coarse-sediment production based on discharge alone would be inaccurate. A nonglaciated basin proximal to the Matanuska Glacier terminus yielded higher bedload sediment fluxes and larger clast sizes than delivered by the two monitored vents. Such nonglaciated basins should not be overlooked as potentially major sources of coarse bedload that is reworked and incorporated into valley outwash.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Bedload component of glacially discharged sediment: Insights from the Matanuska Glacier, Alaska
Series title:
Geology
DOI:
10.1130/0091-7613(2003)031<0007:BCOGDS>2.0.CO;2
Volume
31
Issue:
1
Year Published:
2003
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geology
First page:
7
Last page:
10