Lake Lapworth was a postulated

glacial lake A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10,0 ...

Great Britain Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...

, believed to have formed during the last ice age when

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...

s ended the northern outlet of the

Severn , name_etymology = , image = SevernFromCastleCB.JPG , image_size = 288 , image_caption = The river seen from Shrewsbury Castle , map = RiverSevernMap.jpg , map_size = 288 , map_c ...

. This ran through the Dee (which passes by

Chester Chester is a cathedral city and the county town of Cheshire, England. It is located on the River Dee, close to the English–Welsh border. With a population of 79,645 in 2011,"2011 Census results: People and Population Profile: Chester Loca ...

). At some point or points it ran into glaciers and backed up to form a resultant lake. This overflowed southwards cutting the

Ironbridge Gorge The Ironbridge Gorge is a deep gorge, containing the River Severn in Shropshire, England. It was first formed by a glacial overflow from the long drained away Lake Lapworth, at the end of the last ice age. The deep exposure of the rocks cut t ...

, near

Telford Telford () is a town in the borough of Telford and Wrekin and ceremonial county of Shropshire, England, about east of Shrewsbury, south west of Stafford, north west of Wolverhampton and from Birmingham in the same direction. With an est ...

Shropshire Shropshire (; alternatively Salop; abbreviated in print only as Shrops; demonym Salopian ) is a landlocked historic county in the West Midlands region of England. It is bordered by Wales to the west and the English counties of Cheshire to th ...

. This permanently diverted most of the Severn drainage basin to its current basin which flows south.

Etymology

The lake was named in 1924 by

Leonard Johnston Wills Professor Leonard Johnston Wills (1884–1979) – known as 'Jack' to friends and family – was one of the leading British geologists of his generation. He held the Chair of Geology at the University of Birmingham from 1932 to 1949, and received m ...

for the late

Charles Lapworth Charles Lapworth FRS FGS (20 September 1842 – 13 March 1920) was a headteacher and an English geologist who pioneered faunal analysis using index fossils and identified the Ordovician period. Biography Charles Lapworth was born at Faring ...

( 1920), who suggested its existence in 1898. Frederic William Harmer (1835-1923) proposed the same causation and timing in 1907 having considered glacial lake sediments found on the

Plain.

Geography and geology

Lake Lapworth is one of several glacial lakes that are thought to have existed during the Ice Age in the late

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

. This was the geological

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

that lasted from about 2,580,000 to 11,700 years ago, spanning the world's most recent period of repeated

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betw ...

Aqualate Mere Aqualate Mere, in Staffordshire, is the largest natural lake in the English Midlands and is managed as a national nature reserve (NNR) by Natural England. The Mere lies within the borough of Stafford in Staffordshire, England, some east of th ...

is a remnant of Lake Lapworth. The flood that carved Ironbridge gorge exposed deposits of

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...

fireclay Fire clay is a range of refractory clays used in the manufacture of ceramics, especially fire brick. The United States Environmental Protection Agency defines fire clay very generally as a "mineral aggregate composed of hydrous silicates of alumin ...

and

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

. The existence of these minerals and ore in close proximity contributed to the development of the

ironworks An ironworks or iron works is an industrial plant where iron is smelted and where heavy iron and steel products are made. The term is both singular and plural, i.e. the singular of ''ironworks'' is ''ironworks''. Ironworks succeeded bloomeri ...

that started the

Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...

in the 18th century. The market town of

Newport, Shropshire Newport is a constituent market town in Telford and Wrekin in Shropshire, England. It lies north of Telford, west of Stafford, and is near the Shropshire-Staffordshire border. The 2001 census recorded 10,814 people living in the town's parish ...

, sits atop a

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

ridge, which in the last ice age was an island or peninsula in Lake Lapworth. Long after the supposed lake had vanished, early man fished here, and two

log boats A dugout canoe or simply dugout is a boat made from a hollowed tree. Other names for this type of boat are logboat and monoxylon. ''Monoxylon'' (''μονόξυλον'') (pl: ''monoxyla'') is Greek – ''mono-'' (single) + '' ξύλον xylon'' (t ...

were uncovered from Newport. One has been preserved and is now at

Harper Adams University Harper Adams University, founded in 1901 as Harper Adams College, is a public university located close to the village of Edgmond, near Newport, in Shropshire, England. Established in 1901, the college is a specialist provider of higher educat ...

Edgmond Edgmond is a village in the borough of Telford and Wrekin and ceremonial county of Shropshire, England. The village population at the 2011 Census was 2,062. It lies north-west of the town of Newport. The village has two pubs (the Lion and t ...

Re-evaluation

Wills' theory was widely accepted until the 1980s but research starting in the 1970s had shown the existence of a bedrock trench, up to 120m in depth, beneath the course of the Severn running east from the

Melverley Melverley is a village in Shropshire, England, situated on the River Severn and the River Vyrnwy, near the Powys hills and the border with Wales. The population of the civil parish at the 2011 census was 156. The village, and the large rural a ...

area beneath Shrewsbury to the head of the Ironbridge Gorge. It is but one of several such buried trenches known beneath the surface of Shropshire and Cheshire whose form indicates erosion by sub-glacial meltwater under considerable pressure, the long profile of this and others being undulating, i.e. with water flowing uphill in certain sections. It is postulated that this sub-glacial version of the Severn rose to the surface at the ice front and cut the gorge; no lake is required in this scenario. The process may have been initiated during the

Anglian glaciation The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. The Anglian Stage is correlated to Marine Isotope Stage 12 (MIS 12), ...

of 450,000 years ago and continued during the Devensian. Other work on features interpreted as the shoreline of Lake Lapworth has revealed that the levels do not match from one area to another leaving open the possibility of multiple smaller lakes having existed at different times, rather than one large one.

References

External links

Secret Shropshire
{{coord missing, Shropshire

Lapworth Lapworth is a village and civil parish in Warwickshire, England, which had a population of 2,100 according to the 2001 census; this had fallen to 1,828 at the 2011 Census. It lies six miles (10 km) south of Solihull and ten miles (16&nbs ...

Geography of Newport, Shropshire Geology of Shropshire History of Shropshire