The Lake District, Northwest England

Abstract

The Lake District in the northwest of England contains dramatic scenery associated with the deeply dissected Cumbrian Mountains. The Lake District National Park is the most widely visited rural area in the British Isles, with tourists attracted by outdoor activities including a network of mountain footpaths. Lakes including Coniston Water, Buttermere, Derwent Water, Ullswater, and Windermere are widely known. Scafell Pike is the highest summit in England. Human settlement in the Lake District is traced to Neolithic times. The mining heritage dates from the Romans who constructed transport routes for exporting lead and silver. Mining of copper and graphite was of particular importance during the Elizabethan times, and the Victorian period saw development of extensive copper and lead workings. The high quality, dark blue-grey slate from the Lake District roofs famous buildings in London. The combination of mountainous landscapes and tranquil valleys has inspired a long association with English literature and artists, and the region includes cultural centres associated with literary greats such as William Wordsworth and John Ruskin. The geomorphology of the Lake District is dominated by the ice-sculptured Cumbrian Mountains. Deeply-incised valleys radiate outward from the mountainous core. Valleys contain finger-lakes which developed as the Late Pleistocene ice sheets and glaciers retreated. Scree slopes and rocky summits (pikes) formed due to ice and frost erosion. Hanging valleys with small Alpine lakes and fast-flowing streams are an integral part of the topography. The geological setting is dominated by an inlier of Lower Palaeozoic strata, one of a number of disjointed terrains collectively known as the British Caledonides. Each of the Lower Palaeozoic inliers was subjected to the Caledonide Orogeny. The orogeny peaked in the Early Devonian. The oldest component of the Lake District inlier is the Skiddaw Group, a thick sequence of Lower Ordovician mudstones and shales. These rocks are associated with the rounded massifs in the northern part of the region. The mudstones and shales are unconformably overlain by the Borrowdale Volcanic Group, a succession of mostly sub-aerial calc-alkaline lavas, ashes, and volcaniclastics associated with a Mid-Ordovician volcanic island arc. The Borrowdale volcanics constitute the rugged mountains in the core of the inlier. Some of the volcanic ashes have a prominent cleavage and form high-quality slate deposits. The Windermere Supergroup, which is associated with the gently rolling hills that characterize the southern part of the Lake District, marks a marine transgression in the Upper Ordovician and Silurian. Thick sequences of limestone and shale were deposited in shallow seas rich in marine fossils. The regional unconformity separating the Borrowdale Volcanics from the Coniston Limestone is demarcated by a marked change in the topography. Two groups of intrusive igneous rocks occur in the Lake District inlier. Small bodies of Mid-Ordovician granite and gabbro are associated with many of the ore deposits. The buoyancy of a low-density, Devonian-age, granitic batholith located at depth is in part responsible for uplifting the mountainous core of the Lake District.