Nan Bield Pass

Hill passes of the Lake District were originally used by people in one valley travelling to another nearby without having to go many miles around a steep ridge of intervening hills. Historically, in the Lake District of northwest England, travel on foot or by pony was difficult because of the region's steep-sided valleys so tracks across the ridges were created taking the easiest route over passes – often, but not always, via a col. Since Roman times long-distance travel had tended to be along ridges. From the 19th century these passes and ridge routes were brought back into use when recreational hill walking become popular. Forty hill passes within the Lake District National Park are listed here, using criteria for selecting the major routes.

The Lake District National Park was created in 1951 covering an area of over 2,000 square kilometres (770 sq mi) and, although its population is only 42,000, over 10 million visitors arrive each year, mostly attracted by the lakes and fells.

About 500 million years ago in the late Cambrian and early Ordivician periods, the region was situated where the Iapetus ocean floor was being subducted under the Avalonia plate. Sedimentary material became metamorphosed to the Skiddaw slates found in the north and west. For a relatively short time of 5 million years Ordovician volcanoes ejected the Borrowdale volcanic rocks – firstly lavas (mostly andesite} and later pyroclastic rocks found in the more central part of the region. The ejection of rock was extreme by world standards and it produced deposits at least 6,000 metres (20,000 ft) deep. When the Baltica-Avalonia and Laurentia continents collided some 420 million years ago in the Caledonian orogeny there was folding of the slate and fracturing (faulting) of the more brittle volcanic rock. The whole region was then uplifted again by a batholith of granite mainly in the Carboniferous period although the granite remains largely below the surface. The high ground became gradually eroded and to the south the land subsided. In the south 8,000 metres (26,000 ft) of Windermere Supergroup sediment formed in the Silurian period with Coniston Limestone towards its base. Overall cover of limestone eroded away.

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Wikipedia