What lurks in Antarctica’s bedrock? BAS
Almost 100 volcanoes have been newly identified beneath the ice covering West Antarctica. It鈥檚 not yet known whether they鈥檙e active, but if they are, it could spell added trouble for ice sheets already in retreat because of global warming.
鈥淚f they erupted, they would create water beneath the ice,鈥 says at the University of Edinburgh, UK. 鈥淭hat would make the ice above flow faster, so it would have the potential to increase the losses of ice we鈥檙e already seeing.鈥
Bingham and his colleagues identified the volcanoes by examining an existing data set called Bedmap2, a collection of ground-penetrating radar scans made from aeroplanes or vehicles above or on the surface.
Advertisement
How will we know when we’ve reached the tipping point on climate change?
The scans show the profile of the rock some 4 kilometres beneath the ice, and the team identified all conical structures as possible volcanoes. 鈥淣o one had interrogated the data before for shapes,鈥 says Bingham.
Counting cones
Next, the researchers checked to see whether the cones tallied with other data from satellite imagery, such as subtle deformations on the ice surface directly above possible volcanoes, and telltale variations in gravity and magnetic fields. 鈥淲e found 180 cones, but discounted 50 because they weren鈥檛 matched with the other data,鈥 says Bingham.
They settled on a final tally of 138 beneath the West Antarctic ice sheet, which includes 47 volcanoes already known because their peaks protrude through the ice 鈥 leaving 91 newly discovered. The volcanoes range in height from 100 to 3850 metres, with 29 higher than 1 km.
Bingham suspects that more volcanoes may lurk beneath the neighbouring Ross ice shelf, for which ground-penetrating radar information is sparse. If so, it could mean that the West Antarctic ice sheet and the adjoining area hide one of the world鈥檚 largest volcanic systems, comparable with the largest known 鈥 the East African rift system.
The team now wants to deploy instruments to find out how active the volcanoes are.
But even if they are active, at NASA鈥檚 Jet Propulsion Laboratory in Pasadena, California, thinks the effect on the ice will be relatively minor 鈥 and that the main threat to the ice sheets is warmer ocean water. 鈥淭his ocean heat largely surpasses what could ever be produced by a few active volcanoes,鈥 he says.
Journal reference: Geological Society, London, Special Publications, DOI:
Topics:
