The North Pennines owes much of its character to the action of ice and water during and after the last ice age. Glaciers and meltwater scoured the landscape, depositing glacial debris and creating a range of landforms.
A blanket of ice
Over the past 2 million years the North Pennines has been covered in ice many times. Ice ages alternated with warmer periods when the climate was similar to, or even warmer than, our climate today. At the height of the last major glaciation, about 20,000 years ago, most of northern Britain was ice-covered, and the North Pennines lay under up to a kilometre of ice.
Deposits and drumlins
Ice streamed from west to east, grinding down the land surface and carrying vast amounts of sediment. It smeared a mixture of clay, gravel and boulders known as ’till’ over the landscape, and created streamlined mounds called ‘drumlins’. Meltwater flowing beneath and around the ice carved meltwater channels and deposited sand and gravel.
After the ice
About 15,000 years ago the climate started to become warmer and wetter. The ice began to melt, leaving a barren landscape of bare rock, unstable slopes and glacial debris. Repeated freezing and thawing in the tundra-like conditions caused landslips on unstable hill slopes and created blockfields of frost-shattered rock.
After the ice came arctic plants and shrubs, and tundra animals such as reindeer and arctic fox. Gradually, arctic scrub was replaced by woodland which covered all but the highest hilltops and was home to wild boar, wolf and red deer. By 8,000 years ago, people were living here. Around 7,000 to 5,000 years ago, a period of cold, wet climate, perhaps combined with woodland clearance by people, led to the development of peat on the uplands.