Glaciovolcanic sequences and reconstructing past Antarctic ice sheets

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• Professor John Smellie (University of Leicester, Dept of Geology)
• Monday 26 November 2012, 17:00-18:00
• Harker Room 1, Department of Earth Sciences.

If you have a question about this talk, please contact Lois Salem.

Subglacially erupted volcanoes are keystone elements of many glaciated terrains, past and present. Over the past decade, rapid developments in our understanding of the glaciovolcanic sequences thus formed have enabled them to become one of the most powerful proxies in existence for reconstructing past ice sheets. This will be demonstrated with reference to successive recent investigations in Victoria Land, Antarctica, where multiple volcanic sequences crop out with ages extending between Late Miocene (c. 10 Ma) and late Pleistocene. The results of those studies demonstrate clearly that the volcanic rocks were erupted in association with a relatively thin ice sheet, typically just a few hundred metres in thickness, a conclusion substantially different from all previous studies. Moreover, they have provided unequivocal information on the thermal regime of the ice cover and how it varied spatially and temporally. The latter finally resolves a major palaeoenvironmental controversy that has raged for more than 30 years over the timing of the transition to a stable Antarctic ice sheet and has important implications for understanding temporal variations of global sea level. The studies demonstrate that the arguments that have separated the two polarised scientific groups are fatally undermined and therefore anachronistic. No other methodology has been capable of resolving this controversy and the results serve to illustrate the increasing power of palaeoenvironmental investigations that incorporate, or are led by, studies of glaciovolcanic sequences.

This talk is part of the Sedgwick Club talks series.

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• Department of Earth Sciences seminars
• Harker Room 1, Department of Earth Sciences
• Sedgwick Club talks

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