Research Article

Quantifying periglacial erosion: insights on a glacial sediment budget, Matanuska Glacier, Alaska

  1. Colin R. O'Farrell1,
  2. Arjun M. Heimsath2,*,
  3. Daniel E. Lawson3,
  4. Laura M. Jorgensen4,
  5. Edward B. Evenson5,
  6. Grahame Larson6,
  7. Jon Denner7

Article first published online: 13 NOV 2009

DOI: 10.1002/esp.1885

Issue

Earth Surface Processes and Landforms

Earth Surface Processes and Landforms

Volume 34, Issue 15, pages 2008–2022, December 2009

Additional Information

How to Cite

O'Farrell, C. R., Heimsath, A. M., Lawson, D. E., Jorgensen, L. M., Evenson, E. B., Larson, G. and Denner, J. (2009), Quantifying periglacial erosion: insights on a glacial sediment budget, Matanuska Glacier, Alaska. Earth Surface Processes and Landforms, 34: 2008–2022. doi: 10.1002/esp.1885

Author Information

  1. 1

    Pioneer Natural Resources, 1401 17th St., Suite 1200, Denver, CO 80202, USA

  2. 2

    School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA

  3. 3

    CRREL, 72 Lyme Rd., Hanover, NH 03755, USA

  4. 4

    The Shaw Group, 7604 Technology Way #300, Denver, CO 80237, USA

  5. 5

    Dept. of Earth and Environmental Sciences, Lehigh University, Bethlehem, PA 18015, USA

  6. 6

    Dept. of Geological Sciences, Michigan State University, East Lansing, MI 48824, USA

  7. 7

    USGS, Federal Building, Montpelier, VT 05601, USA

*School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA

Publication History

  1. Issue published online: 26 NOV 2009
  2. Article first published online: 13 NOV 2009
  3. Manuscript Accepted: 6 JUL 2009
  4. Manuscript Revised: 25 JUN 2009
  5. Manuscript Received: 7 MAR 2008

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Keywords:

  • periglacial erosion;
  • sediment yield;
  • glaciation;
  • 10Be;
  • cosmogenic nuclides

Abstract

Glacial erosion rates are estimated to be among the highest in the world. Few studies have attempted, however, to quantify the flux of sediment from the periglacial landscape to a glacier. Here, erosion rates from the nonglacial landscape above the Matanuska Glacier, Alaska are presented and compare with an 8-yr record of proglacial suspended sediment yield. Non-glacial lowering rates range from 1·8 ± 0·5 mm yr−1 to 8·5 ± 3·4 mm yr−1 from estimates of rock fall and debris-flow fan volumes. An average erosion rate of 0·08 ± 0·04 mm yr−1 from eight convex-up ridge crests was determined using in situ produced cosmogenic 10Be. Extrapolating these rates, based on landscape morphometry, to the Matanuska basin (58% ice-cover), it was found that nonglacial processes account for an annual sediment flux of 2·3 ± 1·0 × 106 t. Suspended sediment data for 8 years and an assumed bedload to estimate the annual sediment yield at the Matanuska terminus to be 2·9 ± 1·0 × 106 t, corresponding to an erosion rate of 1·8 ± 0·6 mm yr−1: nonglacial sources therefore account for 80 ± 45% of the proglacial yield. A similar set of analyses were used for a small tributary sub-basin (32% ice-cover) to determine an erosion rate of 12·1 ± 6·9 mm yr−1, based on proglacial sediment yield, with the nonglacial sediment flux equal to 10 ± 7% of the proglacial yield. It is suggested that erosion rates by nonglacial processes are similar to inferred subglacial rates, such that the ice-free regions of a glaciated landscape contribute significantly to the glacial sediment budget. The similar magnitude of nonglacial and glacial rates implies that partially glaciated landscapes will respond rapidly to changes in climate and base level through a rapid nonglacial response to glacially driven incision. Copyright © 2009 John Wiley & Sons, Ltd.

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