I came across this image of flowing lava in an eruption on Hawaii in 2010. Lava is extremely hot, becoming more viscous as it cools down. The fun thing is that ice behaves in a similar fashion when it is flowing at an optimal rate -- but then it ceases to flow when the temperature rises, so that melting, and the conversion to water, destroys the flow structures which are not dissimilar to those of flowing lava.
Lava flows, and glaciers, tend to seek out depressions and fill them -- subsequently overflowing via cols or low points in the depression rims.
Most of the movement of ice occurs through internal deformation and basal sliding -- but there is also brittle fracture which results in crevasse formation, and the creation of shear fractures and thrust planes partucularly in cold or polar ice.
Here are a few images of flowing glacier ice in Arctic Canada and Alaska:
I have seen similar ephemeral features on small glaciers in East Greenland.
4 comments:
Did you see the article on " ice piracy " being committed in the Antarctic?
No -- where was this?
Kohler East and West Glaciers if memory serves.
Thanks Gordon. The rather colourful language used by the authors in their press release is entertaining, but a bit over the top! This sort of "piracy" is not that unusual -- if you look on Google Earth at the glaciers of Baffin, Greenland and other areas in the Arctic, you see strong evidence of converging ice streams where one or the other achieves "dominance" and apparently gobbles up its neighbour. You might even get6v reversals of ice flow direction. Surging behaviour is often a part of the scenario -- the interesting thing in the Antarctic case is that grounding lines and floating ice fronts are parts of the scenario. The article is here: https://tc.copernicus.org/articles/19/1725/2025/
Post a Comment