Jackson, Ian. Cumbria Rocks — 60 extraordinary rocky places that tell the story of the Cumbrian landscape. Newcastle upon Tyne : Northern Heritage, 2022.
The richly illustrated and accessible book series of Cumbria, Northumberland and Durham Rocks are available to purchase from Northern Heritage.
Theme: Volcanoes and molten rock
16 Ennerdale. Parking is at the west end of the lake. For a stunning view climb Angler’s Crag
If you were to ask someone who knows the Lakes well in which valleys would you find most peace, they would probably include Ennerdale.
Cumbria’s most westerly finger lake sits in a beautiful glacial valley. Its location and the absence of public roads are the reason for its tranquillity. At the valley’s western end are 475-million-year-old, bent and fractured mudstones and sandstones; go east of Angler’s Crag and the bedrock is Ennerdale Granite. Once called the Ennerdale Granophyre, detailed work by a British Geological Survey team in the 1980’s and 90’s, covering all Lake District rocks, produced a more up-to-date identification. Technically the rock is a ‘granophyric microgranite’; which means it has small, interlocking mineral crystals. Geophysical and geochemical investigations showed the microgranite to be around 1–2 kilometres thick, to extend over 53 square kilometres and to have been intruded around 450 million years ago. At the head of Ennerdale the conspicuous mounds are moraines, deposited by a small glacier which reformed in a short return of a cold climate about 12,000 years ago.
Ennerdale’s secrets extend to much more than its rocks. The lake is home to the rare Arctic Char, a throwback to Ice Age times and a fish more common in lakes in the north of Canada. On the bed of the River Ehen, the valley’s outflow, are equally rare Freshwater Pearl Mussels. Their rarity and environmental sensitivity were the catalyst for a recent £300 million alternative water supply scheme to ensure the lake would continue to sustain the river. The Wild Ennerdale project has ambitious plans to re-wild the valley, including re-introducing beavers. On the floor of the valley near Low Gillerthwaite are mounds of stones. These are a ‘cairnfield’ or clearance cairns, evidence of the creation of pastureland by the clearing of forest by Bronze and Iron Age peoples 5000 and 3000 years ago. The cairnfield here is now threatened by erosion by the River Liza; as ever geological processes are indifferent to human accomplishments.