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However, the following information can be derived routinely from glaciovolcanic sequences [1,3,4]: These questions are important because answering them will help us understand past ice-sheet responses to environmental change – and this will help us to predict future change better. Because the volcanic sequences are typically quite thick (hundreds of metres) and contain resistant rocks such as lavas, they are able to persist through multiple overriding events by ice, unlike many much thinner (typically just metres) glacial sediments.However, volcanic eruptions commonly occur at intervals of several tens to hundreds of thousands of years.
As well as providing invaluable information on the construction of volcanoes in a uniquely hostile and inaccessible environment, important when predicting the consequences of modern glaciovolcanic eruptions (e.g.
Eyjafjallajokull in Iceland, 2010), studies on subglacial volcanoes have also been developed into what is probably now the most powerful methodology for deriving multiple critical parameters of past ice sheets, mainly the Antarctic Ice Sheet [e.g. Studies of past ice sheets using glaciovolcanic outcrops are still in their infancy.
Thus, the volcanic record is coarse in resolution, comparable with terrestrial glacial sediments but generally worse than in marine sediments.
Antarctica is the largest glaciovolcanic province in the world.
There are many volcanoes and they occur all the way from the sub-Antarctic South Sandwich Islands, through the Antarctic Peninsula and Marie Byrd Land, and into East Antarctica, a distance of about 5000 km.
Eruptions coincided with the development of the Antarctic Ice Sheet.
In places such as northern Victoria Land, cliff sections up to 2 km high extend 10 or 20 km laterally .
However, many volcanoes have minimal exposure or have been extensively removed by multiple overriding ice sheets, particularly in the Antarctic Peninsula.
The volcanoes are overwhelmingly basaltic and there are few examples of more evolved magmatic compositions [6,7].
They range from very large stratovolcanoes with summit elevations up to 4000 m above sea level and basal diameters of 40 to 60 km, to volcanic fields composed multiple small centres [6,9].