Knockan Crag National Nature Reserve

Knockan Crag National Nature Reserve
The Moine Thrust fault at Knockan Crag
Map showing the location of Knockan Crag National Nature Reserve
Location Ross-Shire and Sutherland, Highland, Scotland
Coordinates 58°02′20″N 5°03′44″W / 58.03887°N 5.06212°W / 58.03887; -5.06212Coordinates: 58°02′20″N 5°03′44″W / 58.03887°N 5.06212°W / 58.03887; -5.06212
Established 2004
Governing body Scottish Natural Heritage (SNH)
Knockan Crag
Knockan Crag visitor centre

Knockan Crag National Nature Reserve lies within the North West Highlands Geopark in the Ross-Shire and Sutherland border area of Scotland 21 kilometres (13 mi) north of Ullapool. It is centred on the Knockan Crags cliffs, a Site of Special Scientific Interest.

The Moine Thrust Belt runs through the crag and there is a small visitor centre that explains the background to the 'Highlands Controversy' concerning the geology of the area.

The Globe

Scottish Natural Heritage provides an interpretation centre, car park and various walks along the crag explaining the features and including artwork such as 'The Globe' by Joe Smith.

Name

Knockan Crag is an anglicisation of the Gaelic Creag a' Chnocain meaning 'crag of the small hill'.[1]

National Nature Reserve

The Knockan Crag National Nature Reserve is managed by Scottish Natural Heritage and is designated for its outstanding geological features.

Knockan Crag was declared a National Nature Reserve (NNR) on 25th February, 2004. Knockan Crag NNR is owned and managed by Scottish Natural Heritage (SNH) and is part of the wider Knockan Crag Cliff Site of Special Scientific Interest. It also lies within the North West Highlands Geopark, part of the International Network of Geoparks.[2]

Scottish Natural Heritage provides an interpretation centre, car park and various walks along the crag explaining the features and including artwork such as 'The Globe' by Joe Smith.

Geological significance

The Moine Thrust runs through the crag and there is a small visitor centre providing interpretation and artwork that explains the background to the 'Highlands Controversy' concerning the geology of the area.

Highlands Controversy

During the 19th century prominent geologists conducted a prolonged and bitter debate about the fault line exposed here. The argument was primarily between Roderick Murchison and Archibald Geikie on the one hand and James Nicol and Charles Lapworth on the other. This was finally resolved by the work of Ben Peach and John Horne whose 1907 paper on the subject remains a classic text.[3][4]

The main issue was that the Moine schists at the top of the crag appeared to be older than the Cambrian and Ordovician rocks such as Durness limestone lower down. Murchison and Geikie believed the sequence was wrong and that the Moine schists must be the younger rocks. The conundrum was explained by the action of a thrust fault - this being the first to be discovered anywhere in the world. The older rocks had been moved some 70 kilometres to the west over the top of the younger rocks due to tectonic action.[5][6]

A monument to Peach and Horne's work was erected by the international geological community at Inchnadamph, a few miles to the north.

See also

References

  1. ↑ "Knockan Crag National Nature Reserve". Scottish Natural Heritage. Retrieved 2007-09-08.
  2. ↑ North West Highlands Geopark. North West Highlands Geopark. Retrieved 18 August 2007.
  3. ↑ Peach, B.N., Horne, J., Gunn, W., Clough, C.T., Hinxman, L.W., and Cadell, H.M. (1888) Report on the recent work of the Geological Survey in the north-west Highlands of Scotland, based on field notes and maps by Messrs. B.N. Peach, J. Horne, W. Gunn, C.T. Clough, L.W. Hinxman, L.W. and H.M. Cadell. Quarterly Journal of the Geological Society of London, 44, 378-441.
  4. ↑ Peach, B.N., Horne, J., Gunn, W., Clough, C.T., and Hinxman, L.W., (1907) The Geological Structure of the Northwest Highlands of Scotland. Memoirs of the Geological Survey of Great Britain.
  5. ↑ Dryburgh, P. M. et al. (1995) Assynt: The geologists' Mecca. Edinburgh Geological Society.
  6. ↑ Oldroyd, David R (1990). The Highlands Controversy. Chicago: The University of Chicago Press. ISBN 0-226-62635-0.

Further reading

  • Johnstone, G.S. (1989). The Northern Highlands of Scotland. British Regional Geology (4th ed.). Her Majesty's Stationery Office (HMSO). . The full text of the Third Edition of this publication (Phemister, 1960) can be found at "Archive.org".
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