The North Pennine Batholith, also known as the Weardale Granite is a granitic

batholith A batholith () is a large mass of intrusive igneous rock (also called plutonic rock), larger than in area, that forms from cooled magma deep in Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such ...

lying under northeast England, emplaced around 400 million years ago in the early

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

.Kimbell, G.S., B. Young, D. Millward and Q. G. Crowley (2010). 'The North Pennine batholith (Weardale Granite) of northern England: new data on its age and form', ''Proceedings of the Yorkshire Geological Society'' 58, 107-128; do
10.1144/pygs.58.1.273
/ref> The batholith consists of five

pluton 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 ...

s, the Tynehead, Scordale, Rowlands Gill, Cornsay and Weardale plutons. The Weardale Granite pluton is the largest and the only one that has been proved (sampled), after the Rookhope Borehole confirmed Martin Bott's hypothesis that a large negative gravity anomaly under Weardale represented a low-density igneous intrusion.

History of Study

In 1934,

Kingsley Dunham Sir Kingsley Charles Dunham (2 January 1910 – 5 April 2001) was one of the leading British geologists and mineralogists of the 20th century. He was a Professor of Geology at the University of Durham from 1950–71. He was later Professor Emeri ...

published a paper proposing that ore deposits in the

Alston Block The Alston Block is a term used by geologists to describe the geological structure of the North Pennines of northern England and which forms a part of the Pennine Block & Basin Province which originated during the Carboniferous period. It is defin ...

were formed due to a granite intrusion beneath Weardale. This was later tested by a gravity survey, which found a large negative gravity anomaly, supporting the hypothesis. In the early 1960s, a borehole was drilled at Rookhope by

Durham University , mottoeng = Her foundations are upon the holy hills (Psalm 87:1) , established = (university status) , type = Public , academic_staff = 1,830 (2020) , administrative_staff = 2,640 (2018/19) , chancellor = Sir Thomas Allen , vice_chan ...

, and proved the existence of the intrusion at a depth of 390 m. The intrusion was found to have a weathered top, so couldn't account for the mineralisation that was the basis of the hypothesis that first suggested its existence. In 2004, a second borehole was drilled in

Eastgate Eastgate may refer to: Places Canada * Eastgate, Alberta, Canada * Eastgate, British Columbia, Canada United Kingdom * Eastgate, County Durham, England * Eastgate, Norfolk, England * Eastgate, Peterborough, Cambridgeshire, England * Eastgate, C ...

, and the granite was reached at 270 m below the surfaceManning D.A.C., P.L. Younger, F.W. Smith, J.M. Jones, D.J. Dufton and S. Diskin (2007), 'A deep geothermal exploration well at Eastgate, Weardale, UK: a novel exploration concept for low-enthalpy resources', ''Journal of the Geological Society, London'' 164, 371–382; do
10.1144/0016-76492006-015
/ref>

References

{{reflist Geology of the Pennines Batholiths of Europe Devonian magmatism

History of Study

See also

References