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It has been suggested that this article or section be merged into glacial lake outburst flood. (Discuss) |
A jökulhlaup (or glacier burst) is a glacial outburst flood. The name is an Icelandic term that has been adopted by the English language. It originally referred to the well-known subglacial outburst floods from Vatnajökull, Iceland which are triggered by a volcanic subglacial eruption, but now it may describe any large and abrupt release of water from a subglacial lake. Jökulhlaups may be generated by the drainage of sub-glacial or pro-glacial reservoirs.
Since jökulhlaups emerge from hydrostatically-sealed lakes with floating levels far above the threshold, their peak discharge can be much larger than that of a marginal or extra-marginal lake burst. The hydrograph of a jökulhlaup from Vatnajökull typically either climbs during weeks with the largest flow near the end, or it climbs much faster during the course of hours. This is suggested to reflect channel melting, and sheet flow under the front, respectively.[1]
Whilst jökulhlaups are usually associated with Vatnajökull, they have been observed indirectly under the present day Antarctic, and it has been suggested that they also occurred from the Laurentian ice sheet[2][3][4][5] and the Scandinavian ice sheet[6] during the last ice age.
References
Sources
- Beaney, C. L. and Shaw, J., (2000). The subglacial geomorphology of southeast Alberta: evidence for subglacial meltwater erosion. Can. J. Earth Sci., 37:51-61.
- Björnsson, H., (2002). Subglacial lakes and jökulhlaups in Iceland. Global and Planetary Change, 35:255–271.
- Alley, R.B., Dupont, T.K., Parizek, B.R., Anandakrishnan, S., Lawson, D.E., Larson, G.J. and Evenson, E.B., (2005). Outburst flooding and the initiation of ice-stream surges in response to climatic cooling: A hypothesis. Geomorphology, 75: 76-89.
- Erlingsson, U., (1994). The ‘Captured Ice Shelf’ hypothesis and its applicability to the Weichselian glaciation. Geogr. Ann., 76A (1–2): 1–12.
- Erlingsson, U., (2008). A jökulhlaup from a Laurentian captured ice shelf to the Gulf of Mexico could have caused the Bølling warming. Geogr. Ann., 90 A (2): 125-140.
- Shaw, J., (1983). Drumlin formation related to inverted melt-water erosional marks. J. Glaciol., 29:461–479.
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