Ice-penetrating radar technology inserted aboard Nasa survey flights has discovered frozen forms of ice blocks at the very bottom of the Greenland ice sheet which are as tall as city skyscrapers and as wide as the island of Manhattan.
Researchers from Columbia University's Lamont-Doherty Earth Observatory said they saw structures spanning over a tenth of northern Greenland. They were formed when the water at the bottom of the ice sheet melted and subsequently re-froze over hundreds to thousands of years.
Know-how: Envirionmental Data Management
