Glaciation: Ice Age in the United Kingdom

The Ice Age is defined as a geological period characterized by average global temperatures that were significantly lower than those observed today.
This climatic shift resulted in the extensive spread and expansion of glaciers across the Earth's surface.
The most recent major cooling phase began approximately $110,000$ years ago, during which the Earth experienced a progressive and intensification of cold conditions.

During this period, a massive ice sheet expanded to cover the majority of Northern Europe and the British Isles.
Within the specific regions covered by the ice sheet, the environment was so extreme that it could not support life: * There were no human inhabitants. * No animal species were present. * The ground was devoid of vegetation, including grass and trees, because of the terminal cold.
The regions of the United Kingdom not buried under the ice sheet were characterized as tundra.
Tundra is defined as land that remains permanently frozen deep below the surface, though the top layer thaws during the summer months.
This thawing process produced thin, boggy soil conditions.
Biological activity in the tundra zones included: * Growth of small plants during the seasonal thaws. * The arrival of large herds of reindeer and antelope from other sectors of Europe, which migrated to graze on the available vegetation. * The presence of megafauna and hardy species such as woolly mammoths, bison, and arctic foxes.
Despite the presence of animals, there were no humans living in these tundra areas during the peak of the glaciation.

Ocean water levels during the Ice Age were significantly lower than contemporary sea levels.
This occurred because a immense volume of the Earth's water was physically locked up in the form of solid ice sheets and glaciers.
As a direct consequence of lower sea levels, water drained away from shallow oceanic regions, exposing the seabed as dry land.
This geographical change caused the United Kingdom to be physically connected to the mainland of Europe, forming a continuous landmass.

Initial Human Presence: Approximately $40,000$ years ago, humans originally arrived in the British Isles by walking over the land bridge from mainland Europe.
Depopulation: As the ice sheet spread and the climate became excessively cold, these human populations were forced to leave the region.
The Glacial Maximum: By $20,000$ years ago, there were no people remaining in the British Isles.
Human Return: About $12,000$ years ago, human populations began to migrate back to the region as the ice sheets started to melt and the climate stabilized.

As the Earth's average temperature warmed, the massive ice sheets began to melt.
The release of meltwater caused global sea levels to rise significantly.
The rising waters eventually submerged the land bridge, separating the United Kingdom from the rest of Europe once again.
This physical separation into an island occurred approximately $8,100$ years ago.

Glacier formation occurs through a specific chronological sequence: 1. Initial Accumulation: Snow must fall and fail to melt completely during the summer season. 2. Seasonal Compaction: During the following winter, new snowfall accumulates on top of the previous year's remnants.