500 million years ago, the oldest rocks in the Lake District sat at the bottom of an ancient sea. Oxygen-poor mud and debris settled on the sea floor and hardened into rock that has persisted over hundreds of millions of years. It is now named the Skiddaw Group, and its rocks are exposed in the northern third of the Lake District.
The southern third of the Lake District consists of slates, siltstones and sandstones. Called the Windemere Group, these rocks formed at the bottom of the ocean about 420 million years ago.
About 400 million years ago, a mountain-building event known as the Caledonian Orogeny thrust all the rocks out of the sea, and magma reshaped the rock layers into complex configurations.
The mountain range may have rivaled the height of today’s Himalayas , but millions of years of erosion wore the rocks down to low-profile hills and by 350 million years ago, the land was once again at the bottom of an ancient ocean. A layer of sea life detritus coated the older rocks, and those fossil shells and corals persist in the Lake District today.
During the Carboniferous Period, mud infiltrated the shallow sea. Some 280 million years ago, another mountain-building event, the Variscan Orogeny, again lifted the rocks.
In the hundreds of millions of years since today’s Lake District rocks formed, they not only rose and fell vertically, they also traveled northward. The rocks of today’s national park sat well south of the equator about 500 million years ago.
In much more recent geologic time 2 million years ago Pleistocene glaciers crept southward to cover most of mainland Britain. The glaciers advanced and retreated multiple times, carving deep valleys that later filled with meltwater and rain. The volcanic rock holds the water in place rather than allowing it to seep out, sustaining the lakes that give the park its name.
More recently, the last ice age, around 20000 years ago, saw an ice slab 900 meters thick (just below the highest Lakeland peaks) cover the park.
And now, all this history AND the countries most beautiful scenery is just a few hours from anywhere in Britain.