Raymond Effect Explained

Raymond Effect is a flow effect in ice sheets, occurring at flow divides, which gives rise to disturbances in the stratigraphy, showing unusual arches or anticlines called Raymond Arches.[1] The stratigraphy is detected by radio-echo sounding. The Raymond Effect arises from the unusual flow properties of ice, as its viscosity decreases with stress.[2] It is of importance because it provides field evidence for the flow properties of ice.[3] In addition, it permits dating of changes in ice flow and the establishment of changes in ice thickness.[4] The effect was first predicted by Charles F. Raymond.[5] Raymond Arches and the Raymond Effect have been observed at numerous other ice divides e.g. Siple Dome,[6] Fletcher Ice Rise, Berkner Island,[7] [8] Roosevelt Island,[4] [8] and Korff Ice Rise.[9]

Ice viscosity is stress-dependent, and in zones where the (deviatoric) stresses are low, the viscosity becomes very high. Near the base of ice-sheets, stress is proportional to the surface slope, at least when averaged over a suitable horizontal distance. At the flow divide, the surface slope is zero, and calculations show that the viscosity increases. This diverts ice flow laterally, and is the cause of the characteristic anticlines, which are in effect draped over the high viscosity area.

Notes and References

  1. Vaughan. David G.. Hugh F. J. Corr . Christopher S. M. Doake . Ed. D. Waddington . Distortion of isochronous layers in ice revealed by ground-penetrating radar. Nature. 25 March 1999. 398. 323–326. 10.1038/18653. 6725. 1999Natur.398..323V . 4414504 .
  2. Glen. J.W.. The creep of polycrystalline ice . 1955. Proceedings of the Royal Society. A228. 1175. 519–538. 10.1098/rspa.1955.0066. 1955RSPSA.228..519G. 138364513.
  3. 1. Gillet-Chaulet. F.. Hindmarsh . R.C.A.. Corr . H.F.J.. King . E.C.. Jenkins . A.. In-situ quantification of ice rheology and direct measurement of the Raymond Effect at Summit, Greenland using a phase-sensitive radar. 2011. Geophysical Research Letters. 38. 24. 10.1029/2011GL049843. 2011GeoRL..3824503G. free.
  4. Conway . H. . B. Hall . G. Denton . A. Gades . E.D. Waddington . Past and future grounding-line retreat of the West Antarctic Ice . . 1999 . 286 . 5438 . 280–283 . 10.1126/science.286.5438.280 . 10514369 .
  5. Raymond C.F. . Deformation in the vicinity of ice divides . . 29 . 357–373 . 1983 . 103 . 10.1017/S0022143000030288 . 1983JGlac..29..357R . free .
  6. Nereson. N.A.. Raymond. C.F.. Jacobel. R.W.. Waddington. E.D.. 2. The accumulation pattern across Siple Dome, West Antarctica, inferred from radar-detected internal layers. Journal of Glaciology. 2000. 46. 152. 75–87. 10.3189/172756500781833449. 2000JGlac..46...75N. 18864009. free.
  7. Hindmarsh. R.C.A. . King. E.C. . Mulvaney. R. . Corr. H.F.J. . Hiess. G. . Gillet-Chaulet. F. . 3 . Flow at ice-divide triple junctions: 2. Three-dimensional views of isochrone architecture from ice-penetrating radar surveys . Journal of Geophysical Research . 116 . F02024 . 2011 . 19 August 2020. 10.1029/2010JF001785. 20.500.11820/68fe4f33-75c6-4e8f-b511-2201147fde24 . 55008674 . free.
  8. Kingslake. J.. Hindmarsh. R.C.A.. Aðalgeirsdóttir. G.. Conway. H.. Corr. H.F.J.. Gillet-Chaulet. F.. Martín. C.. King. E.C.. Mulvaney. R.. Pritchard. H.D. . 3. Full-depth englacial vertical ice-sheet velocities measured using phase-sensitive radar . Journal of Geophysical Research. 2014. 119. 12. 2604–2618. 10.1002/2014JF003275. 2014JGRF..119.2604K. 129824379. free.
  9. Kingslake. J.. Martín. C.. Arthern. R.J.. Corr. H.F.J.. King. E.C.. 2. Ice‐flow reorganization in West Antarctica 2.5 kyr ago dated using radar‐derived englacial flow velocities . Geophysical Research Letters. 2016. 43. 17. 9103–9112. 10.1002/2016GL070278. 2016GeoRL..43.9103K. free.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Raymond Effect".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.