Grain-scale processes, folding, and stratigraphic disturbance in the GISP2 ice core

R. B. Alley, A. J. Gow, D. A. Meese, J. J. Fitzpatrick, E. D. Waddington, J. F. Bolzan

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

Flow disturbances have been shown to alter stratigraphic order in the lower part of the ice sheet in central Greenland. Vertical thin sections of the Greenland Ice Sheet Project 2 ice core show that in the lower 30%, the expected c axis-vertical fabric is interrupted by planes of grains ('stripes') with c axes oriented approximately in the dip directions of the planes. Stripe-parallel shear produces small-scale folds. The stripes can be explained qualitatively by a simple nucleation-and-growth model based on the strong anisotropy of ice-crystal deformation. Nucleation probably is sensitive to spatially variable rates of polygonization, producing spatially variable stripe densities. Stripes are modeled to affect the ice viscosity, so variations in stripe density may contribute to viscosity contrasts that might produce larger deformational features and loss of stratigraphic order.

Original languageEnglish (US)
Pages (from-to)26819-26830
Number of pages12
JournalJournal of Geophysical Research
Volume102
Issue numberC12
DOIs
StatePublished - 1997

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Materials Chemistry
  • Polymers and Plastics
  • Physical and Theoretical Chemistry

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