Vast Geological Structure Hidden Beneath The East Antarctic Ice Sheet

Eddie Gonzales Jr. – MessageToEagle.com – An international team of researchers, including  Durham University’s Department of Geography, has discovered a vast geological structure hidden beneath the East Antarctic Ice Sheet.

Image credit: Wikimedia commons

The structure consists of a group of huge basins hidden beneath ice more than three kilometers thick in some areas.

Together, the basins form a huge, fan-shaped formation that covers much of the continent. The team named it the East Antarctic Fan-shaped Basin Province.

It includes some of Antarctica’s best-known subglacial features, such as the Wilkes and Aurora basins and the basin hosting Lake Vostok, the largest known subglacial lake on Earth.

Although these basins have been individually studied in the past, this is the first time their connection as part of a single coherent structure has been recognized.

Analysis suggests the structure was formed by a process called distributed rotational extension.

This happens when the continental crust spreads out from a central point. The pattern looks like a hand, with the base of the thumb as the fixed point and the fingers spreading out to show the stretching. The spaces between the fingers are like the triangular basins that form as it opens.

The East Antarctic Fan-shaped Basin Province could be one of the largest examples of rotational extension ever seen in continental crust.

It may have formed over several tectonic stages associated with the development of the Gondwana supercontinent and the later split between Antarctica and Australia, and might even have affected this break-up.

The discovery also raises fresh questions – particularly about the structure’s precise age and the geodynamic mechanisms that generated it.

The shape of the bedrock beneath the ice sheet still affects how the ice moves today, controlling where subglacial basins and lakes form. This could affect the stability of parts of the Antarctic Ice Sheet that are especially sensitive to climate change.

To study the structure, researchers combined maps of the land under the ice with geological observations, gravity, magnetic and seismic data, and models of the Earth’s crust and upper layers. They found that the structure results from a deep movement process within the Antarctic Earth’s outer layer.

Dr Guy Paxman from our Department of Geography, who was also involved in this research, led the calculation of how high the land surface of East Antarctica would be if the ice were removed (which would raise the land by up to a meter).

This ‘rebounded topography’ was used in analysis of the orientation and elevation of the topography of the newly discovered structure.

Original source – here

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Written by Eddie Gonzales Jr. – MessageToEagle.com Staff Writer