Research in Iceland

Background to the Research The interesting new work The controversy.... etc...  updated April 2003 Solheimajokull Page More photos from Iceland Leverhulme Project

I've been involved in glacier-related research in Iceland since 1988. I have had the opportunity to take part in some work on glacier-surface ablation, glacial impounding of drainage, and the release of ice-dammed lakes, but my primary interest has been in the origin of basal ice, especially as a geographical counterpoint to my work on that topic in Greenland. I have been fortunate to be able to make observations at most of the glaciers on the southern margins of Myrdalsjokull and Vatnajokull, from Solheimajokull in the west to Breidamerkurjokull in the east.  Most of these observations have been informal, and I have so far not embarked on any serious study of the basal ice or published any observations. I have not been back to Iceland since 1997 but some interesting new material on Icelandic basal ice is appearing in the literature, and my forward planning now includes a return to those old stamping grounds!

The interesting new work that I've been hearing about from Iceland is all to do with a new idea that has been raised by a group of U.S. researchers including Dan Lawson, Ed Evenson, Richard Alley and others. They have suggested, initially on the basis of their well-known work at the Matanuska Glacier in Alaska, that glaciohydraulic supercooling of subglacial water flowing upwards towards the margin through a subglacial basin can cause water to freeze onto the base of a glacier to create basal ice. Several UK researchers associated with an Earthwatch project headed up by Andy Russell at Keele subsequently observed ice at the margin of Skeidararjokull, in southern Iceland, that they believed might fit descriptions of basal ice formed by supercooling at Matanuska. One group of these UK researchers, including Russell, Matthew Roberts and others, have begun work in co-operation with the U.S. group to elaborate the mechanisms of supercooling and basal ice formation at the Icelandic field site. However...

...as with all the most exciting bits of science, not everybody has the same idea about this issue! Supercooling and the origin of basal ice is a controversial topic. The controversy is not about whether it can happen. It's not even about whether it does happen. It's about how widespread it is and about the significance of its impact on both the basal ice layer and the regional hydrology. Some people are saying that the supercooling mechanism contradicts previous theory and must be responsible for basal ice formation at all the other locations where basal ice of a certain type occurs . Other people are saying that the supercooling mechanism complements existing theory, but that it only happens at specific types of location, and that similar types of basal ice can be derived from different  subglacial processes. Some people are saying that extensive layers of basal ice have been formed by this mechanism, while others argue that only localised patches of ice are formed this way, and that many of the extensive basal ice layers that are now being attributed to a supercooling origin are in fact created in other ways. Does supercooling only generate ice at tunnel outlets where rapidly rising subglacial water emerges from the glacier, or does it occur pervasively accross the bed, perhaps even in slow-flowing subglacial groundwater? No one yet knows how ice formed by supercooling, which has a very distinctive physical structure, changes diagenetically in response to glacier flow. If it forms subglacially and then loses its original structure in flowing towards the margin, can it still be differentiated, in ice-margin exposures, from basal ice formed in other ways? Is the chemistry distinctive? The isotope signature? The debris content? The chemical impact on waters in other parts of the system? There are lots of questions, and the answers have lots of implications. So far, very little work has been published, and I have not had the opportunity to see any of the unpublished data, so from my point of view at the moment there seem to be lots of questions and not yet many answers.

I'm very curious! I think I'm going to have to dig out my old notes and photos, and may be go back to the sites where people are seeing this ice, just to have another look for myself! Watch this space...
 
 

In 2003 we have been awarded a grant of ~ £19,000 to carry out research involving new fieldwork in Iceland. This will enable us to follow up some of the issues that have been mentioned on this page... see the Leverhulme Project page for details. I have also mentioned this issue briefly in a "Classics Revisited" review for Progress in Physical Geography in which I contrast the  way in which the supercooling model has been "tested" with the way Kamb and LaChapelle (1964) developed their theories on basal processes. You can read the paper here (.pdf file).
 

Simon Cook has spent 3 years doing his PhD obn this topic, and Debbie and I have worked on the Leverhulme project grant, and done some independent follow up work. Our overall conclusion so far is that SOME of the basal ice may be formed by freezing of supercooled water, but a lot of the ice evan at sites where supercooling occurs doesn't seem to be caused by the supercooling. We are now working to identify diagnostic characteristics of supercooling in basal ice facies, and working to clarify the significance of supercooling both in modern glaciers and in the sedimentary record. A list  of some of our presentations and publications on this topic are on the Leverhulme Project page.