The Acklington 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 northwest of Hawick in southern Scotland east-southeastwards through the Borders region towards the North Sea coast of Northumberland in northern England.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 similar

Cleveland Dyke The Cleveland Dyke (or Armathwaite Dyke, Cleveland-Armathwaite Dyke or Armathwaite-Cleveland Dyke) is an igneous intrusion which extends from Galloway in southern Scotland through Cumbria and County Durham in northern England to the North Yor ...

has been dated to 55.8+/- 0.9 Ma. The dyke is composed of tholeiitic

microgabbro Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grained ...

and basalt Though generally thinner, it is up to 30 m wide in places. It is one of the most significant of a swarm of such intrusions associated with the Mull centre which extend southeastwards through this region, the others being the

and the Blyth and Sunderland subswarms of Northumberland and Tyne and Wear. They are grouped as part of the Mull Dyke Swarm which in turn is a part of the North Britain Palaeogene Dyke Suite The dyke has been worked for roadstone at Acklington in Northumberland.Stone, P. et al. 2010 British Regional Geology: ''Northern England'' (5th edition) (Keyworth, Nottingham. British Geological Survey) p. 243

References

{{Reflist Geology of Scotland Geology of Northumberland Magmatic dikes