Ice sheets repeatedly crept down to cover extensive areas of Britain and Ireland at the start of the Northern Hemisphere ice age — more than 1 million years earlier than previously thought.

Mieke Thierens of University College Cork in Ireland and her co-workers examined sediments deposited in coral carbonate mounds off Ireland's south-west Atlantic coast. Inspection of the grains and chemical analysis of their provenance suggested that the debris was deposited by icebergs calving off from an ice cap covering Britain and Ireland as long ago as 2.6 million years.

Scotland was previously the most southerly area assumed to be glaciated at the time, but it seems that colder climates — driven by changes in the tilt of Earth's axis — spurred ice sheets to encroach on even lower latitudes.

Quatern. Sci. Rev. doi:10.1016/j.quascirev.2010.12.020 (2011)