The Cleveland Dyke (or Armathwaite Dyke, Cleveland-Armathwaite Dyke or Armathwaite-Cleveland Dyke) is an igneous

intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

which extends from Galloway in southern Scotland through Cumbria and

County Durham County Durham ( ), officially simply Durham,UK General Acts 1997 c. 23Lieutenancies Act 1997 Schedule 1(3). From legislation.gov.uk, retrieved 6 April 2022. is a ceremonial county in North East England.North East Assembly �About North East E ...

in northern England to the

North York Moors The North York Moors is an upland area in north-eastern Yorkshire, England. It contains one of the largest expanses of Calluna, heather moorland in the United Kingdom. The area was designated as a national parks of England and Wales, National P ...

in North Yorkshire. The

dyke Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * Dikes, ...

is associated with volcanism which took place at the

Isle of Mull The Isle of Mull ( gd, An t-Eilean Muileach ) or just Mull (; gd, Muile, links=no ) is the second-largest island of the Inner Hebrides (after Skye) and lies off the west coast of Scotland in the Council areas of Scotland, council area of Arg ...

igneous centre in western Scotland during the early Palaeogene Period at a time of regional crustal tension associated with the opening of the north Atlantic Ocean and which resulted in the intrusion of innumerable dykes. The Cleveland Dyke has been dated to 55.8+/- 0.9 Ma. Though generally from 22 to 28 m wide, in places it is up to wide and has been mapped over a distance of . It is the most significant of a swarm of such intrusions associated with the Mull centre which extend southeastwards through this region, the others being the Acklington Dyke and the Blyth and Sunderland subswarms of Northumberland and Tyne and Wear. It was thought traditionally that the entire dyke comprising some of rock was emplaced as a single pulse of magma over a few days, moving southeastwards from Mull but also rising vertically through the

country rock Country rock is a genre of music which fuses rock and country. It was developed by rock musicians who began to record country-flavored records in the late 1960s and early 1970s. These musicians recorded rock records using country themes, vocal s ...

, this mechanism leading in places to the development of ''en echelon'' segments of dyke. However, more recent work suggests that vertical emplacement as a series of thin blades of magma from a series of high level chambers within the crust is more likely. Offsets of the alignment occur within Scotland where the dyke crosses Caledonide fault systems. The dyke is composed of

basaltic andesite Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...

which is amygdaloidal in places. The dyke has been worked for

roadstone A gravel road is a type of unpaved road surfaced with gravel that has been brought to the site from a quarry or stream bed. They are common in less-developed nations, and also in the rural areas of developed nations such as Canada and the Uni ...

at numerous localities including Barrock Fell near Armathwaite in Cumbria and at both Cockfield Fell and Bolam in County Durham.

Setts A sett, also known as a block or Belgian block, is a broadly rectangular quarried stone used in paving roads and walkways. Formerly in widespread use, particularly on steeper streets because setts provided horses' hooves with better grip tha ...

for road construction were made from the dyke at Langbaurgh.

References

{{reflist Geology of Scotland Geology of Yorkshire Geology of North Yorkshire Magmatic dikes