Glimpse into part of Haughmond Hill quarry

Image: © Jeremy Bolwell Taken: 7 Mar 2021

The rock quarried here was laid down around 550 million years ago at a time when 'Britain' was located 60 degrees south of the equator and was part of a super-continent called Gondwana, part of which broke away as tectonic plates shifted and moved inexorably northwards... The oldest rocks here stood as volcanic mountains on the edge of a coastal plain, which was subjected to erosion, creating sand and pebbles. These were flushed down rivers into a network of rivers and estuaries and tumbled and churned, re-deposited etc. At this far remote time in the Earth's history there were no animals or plants with hard skeletons or hard barks, so they left no fossils visible. However fossil ripples remained in shallow waters. These waters were constantly subjected to changing layouts as rivers moved their courses and the two types f rock quarried here were laid down: Conglomerate rock was made of ill-sorted but well rounded pebbles and sand that formed in meandering river channels. Secondly Greywacke a course sandstone formed with a clay matrix formed by flash flood events as rivers burst their banks and lots of fine material was deposited over large areas very quickly. These flood plains later became covered in sea water, which retreated as the late Ordovician Ice Age developed, this led to further erosion and deposition as sea levels rose when the ice ages ended. By the mid-Silurian a tropical sea formed, with coastal reefs and Wenlock Limestone was deposited. In time this led to an arid desert climate and the deposition of sandstones found in North and East Shropshire at Grinshill. All of this was subject to massive pressures within the earth, which often folded hard horizontal rock layers, moving them to almost vertical planes, as found here, especially in the end wall of the quarry. This was later covered by shallow seas, which morphed to deltas and lush tropical swamps, laying down what became coal measures, which were mined at nearby Uffington. The Last Ice Age some 18,000 years ago caused glaciers and ice sheets to carve the rock and landscape and the Severn Valley formed, the river forming a gorge at Ironbridge. Quarrying has occurred here on a large commercial scale since 1950, now used in motorway road surfacing as the stone in asphalt has skid-resistant qualities and is hard-wearing and long lasing. Stone is blasted out, then subjected to primary crushing and then aggregate processing to grade the right sized rocks. Machines called Jaw Crushers and Cone Crushers which are mobile are used to get the perfect product. Fascinating stuff. The quarry company are quick to point out that they have an exit plan and work hard to operate alongside farmers, landowners, the public and wildlife activists to ensure that wildlife thrives here. Apparently the hill supports Muntjac Deer, Peregrine falcons. jackdaws, ravens and in a lagoon some fish. I shared the viewing platform and info boards with a family with a young son who seemed impressed and threw some pebbles into an icy puddle to break the ice. Maybe one day he will work here or become a geologist, or even an environmental activist. Who knows?!?

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