Encyclopedia of Planetary Landforms

2015 Edition
| Editors: Henrik Hargitai, Ákos Kereszturi

Grounding Line System

Reference work entry
First Online:
DOI: https://doi.org/10.1007/978-1-4614-3134-3_376
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Definition

Flowing water-laid sedimentary structure that is formed at glacial terminus, by streamflow beneath a calving ice sheet margin (King and Fader 1986; Alley et al. 1987).

Synonyms

 Till delta

Subtypes

  1. (1)

    Grounding line wedges or till deltas formed by the deformation of subglacial till (and other sediments) that reach the grounding line. These are fan- or wedge-shaped sedimentary units. The mound’s top surface slopes slightly upward in the direction of flow, due to the pressure of the overlying ice shelf (Fig. 1).

     
  2. (2)

    Grounding line fans form where subglacial meltwater streams discharge subaquatically in a marine environment (Powell 1990). These are also named subaqueous esker deltas or beaded  eskers (McMenamin and McGill 2005).

     
  3. (3)

    Morainal banks (moraine ridges, DeGeer moraines) formed by various processes, including pushing. They are often asymmetric, straight, or concave in planform.

     
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References

  1. Alley RB, Blankenship DD, Bentley CR, Rooney ST (1987) Till beneath ice stream B. 3. Till deformation: evidence and implications. J Geophys Res 92(B9):8921–8929CrossRefGoogle Scholar
  2. Grin EA, Cabrol NA (1997) Limnologic analysis of Gusev Crater Paleolake, Mars. Icarus 130(2):461–474CrossRefGoogle Scholar
  3. Hunter LE, Powell RD, Lawson DE (1996) Morainal-bank sediment budgets and their influence on the stability of tidewater termini of valley glaciers entering Glacier Bay, Alaska, U.S.A. Ann Glaciol 22:211–216Google Scholar
  4. King LH, Fader GBJ (1986) Wisconsinan glaciation of the Atlantic continental shelf of southeast Canada. Geological Survey of Canada Bulletin 363, Ottawa, 72 pGoogle Scholar
  5. Lucchitta B (2001) Antarctic ice streams and outflow channels on Mars. Geophys Res Lett 28:403–406CrossRefGoogle Scholar
  6. McMenamin DS, McGill GE (2005) Processes involved in the formation of Martian fan-shaped deposits. 36th Lunar Planet Sci Conf, abstract # 1732, HoustonGoogle Scholar
  7. Powell RD (1990) Glacimarine processes at grounding-line fans and their growth to ice-contact deltas. In: Dowdeswell JA, Scourse JD (eds) Glacimarine environments: processes and sediments. Geological Society, London, 423 pp. Special Publication No. 53Google Scholar
  8. Powell R, Domack E (2002) Modern glaciomarine environments. In: Menzies J (ed) Modern & past glacial environments. Butterworth-Heinemann, Oxford, UKGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.NASA Ames Research Center/NPPMoffett FieldUSA