Drumlin discovered under ice sheet
Scientists from the British Antarctic Survey (BAS) have identified a drumlin – an elongated hill consisting of glacial deposits – being formed under the West Antarctic ice sheet. The surprise discovery is challenging current thinking about how these geological features are formed and ice-sheet behaviour in general.
This is the first time that scientists have been able to study drumlin formation in situ; existing knowledge is based on studies of relic drumlins that were formed thousands of years ago. It has been assumed that they grew gradually as material was deposited, but the new study, published in the journal Geology, has shown that large amounts of sediment are being moved by the Rutford Ice Stream en masse, gathering new material along the way.
The results were collected at three times during the past 13 years using seismic reflection data. This entailed sinking and setting off explosives and measuring the echo off the
river bed to build up a clear picture of its topography. The results shed new light on processes occurring at the bases of ice sheets, which can help with the prediction of glacier flow and subsequent changes in sea level.
This is the first time that scientists have been able to study drumlin formation in situ; existing knowledge is based on studies of relic drumlins that were formed thousands of years ago. It has been assumed that they grew gradually as material was deposited, but the new study, published in the journal Geology, has shown that large amounts of sediment are being moved by the Rutford Ice Stream en masse, gathering new material along the way.
The results were collected at three times during the past 13 years using seismic reflection data. This entailed sinking and setting off explosives and measuring the echo off the
river bed to build up a clear picture of its topography. The results shed new light on processes occurring at the bases of ice sheets, which can help with the prediction of glacier flow and subsequent changes in sea level.
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