A Coupled Ice-Sheet/Ice-Shelf/Sediment Model Applied to a Marine-Margin Flowline: Forced and Unforced Variations

  1. Michael J. Hambrey3,
  2. Poul Christoffersen3,4,
  3. Neil F. Glasser3 and
  4. Bryn Hubbard3
  1. David Pollard1 and
  2. Robert M. Deconto2

Published Online: 24 MAR 2009

DOI: 10.1002/9781444304435.ch4

Glacial Sedimentary Processes and Products

Glacial Sedimentary Processes and Products

How to Cite

Pollard, D. and Deconto, R. M. (2007) A Coupled Ice-Sheet/Ice-Shelf/Sediment Model Applied to a Marine-Margin Flowline: Forced and Unforced Variations, in Glacial Sedimentary Processes and Products (eds M. J. Hambrey, P. Christoffersen, N. F. Glasser and B. Hubbard), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304435.ch4

Editor Information

  1. 3

    Centre for Glaciology, Institute of Geography & Earth Sciences, Aberystwyth University, Wales, Ceredigion SY23 3DB, UK

  2. 4

    Scott Polar Research Institute, University of Cambridge, Lensfield Road, Cambridge, CB2 1ER, UK

Author Information

  1. 1

    Earth System Science Center, Pennsylvania State University, University Park, PA 16802, USA

  2. 2

    Department of Geosciences, University of Massachusetts, Amherst, MA 01003, USA

Publication History

  1. Published Online: 24 MAR 2009
  2. Published Print: 14 DEC 2007

Book Series:

  1. Special Publication Number 39 of the International Association of Sedimentologists

Book Series Editors:

  1. Isabel Montanez

Series Editor Information

  1. University of California, Davis, USA

ISBN Information

Print ISBN: 9781405183000

Online ISBN: 9781444304435

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Keywords:

  • modelling glaciers and ice sheets;
  • coupled ice-sheet/ice-shelf/sediment model applied to marine - margin flowline-forced and unforced variations;
  • preliminary 1-d flowline simulations - with spatial and temporal variations of surface ice mass balance;
  • combined ice sheet-shelf model;
  • sediment model;
  • basic results with climatically forced retreats;
  • sensitivity experiments with climatically forced retreats;
  • combined ice sheet-shelf equations

Summary

A standard large-scale ice-sheet model is extended by (i) adding ice stream-shelf flow using a combined set of scaled equations for sheet and shelf flow, and (ii) coupling with a deforming sediment model that predicts bulk sediment thickness. The combination of sheet and shelf flow equations is heuristic, but allows horizontal shear and longitudinal stretching without a priori assumptions about the flow regime, and a freely migrating grounding line. The sediment model includes bulk transport under ice assuming a weakly non-linear till rheology, and generation of till by glacial erosion. The combined model explicitly simulates off-shore sediment strata, taking one step towards the goal of direct comparisons with Cenozoic glacimarine sediments on Antarctic continental shelves.

Preliminary 1-D flowline simulations are described on a linearly sloping domain, with simple prescribed spatial and temporal variations of surface ice mass balance. Each simulation is run for 10 million years, and the various patterns of offshore sediment strata built up over the course of each run are examined. A wide variety of sediment patterns is produced depending on uncertain model parameters, including unforced irregular oscillations in the absence of external forcing variations. The results are not conclusive, but illustrate the variety of possible interactions that may play a role as more definitive 3-D models become available to link Cenozoic climate variations with the Antarctic sediment record.