North West Highlands Geopark

Last updated

Knockan Crag Knockan Crag.jpg
Knockan Crag

The North West Highlands Geopark is a geopark in the Scottish Highlands. Awarded UNESCO geopark status in 2004, [1] it was Scotland's first geopark, [2] featuring some of the oldest rocks in Europe, around 3,000 million years old. [3] [4] The park contains many notable geological features, such as the Moine Thrust Belt and Smoo Cave and covers an area of around 2,000 square kilometres (770 sq mi). [1]

Contents

Geography

The park is located in the extreme north-west of Scotland and includes parts of Sutherland and Wester Ross, including Cape Wrath. The area is one of the most sparsely inhabited in Europe, [5] and is largely treeless. The park's eastern boundary generally follows the Moine Thrust Belt, otherwise the park is generally bounded by the north and west coasts of Scotland, with a few islands included in the park, such as the Summer Isles. [6]

Notable features

Smoo Cave Entrance to Smoo Cave.jpg
Smoo Cave

The Moine Thrust Belt was formed between 430 and 500 million years ago. The belt includes Precambrian Moine rocks which have been pushed on top of younger Cambrian and Ordovician rocks, much to the surprise of Victorian geologists. [6] [7] A debate ensued between prominent geologists of the time. Roderick Murchison and Archibald Geikie argued that the Moine rocks must in fact be younger than the rocks beneath them, a point of view opposed by James Nicol and Charles Lapworth. The controversy, the so-called "Highlands Controversy", was resolved by Ben Peach and John Horne who found that the Moine rocks had been pushed some 70 kilometres east over the top of the younger rocks by tectonic action. This was the first thrust fault to be discovered. [8] A monument to the pair is located within the park. Its inscription reads: To Ben N Peach and John Horne who played the foremost part in unravelling the geological structure of the North West Highlands 1883–1897. An international tribute. Erected 1930. [9] The fault can be seen most easily at a line of cliffs named Knockan Crag. This crag is where the Moine is where the apparent anomaly in the ages of the rocks was first seen, and is where the thrust belt was first identified. A visitor's centre is located here, as well as several pieces of sculpture created by modern artists. [10]

The area contains a number of limestone caves. The most well known of these is Smoo Cave, a large sea cave near Durness. This cave is unique within the UK in that its outer chamber was formed by the action of seawater, while the inner chambers were formed by fresh water. [11] Its entrance 15 metres high, is the largest entrance of any sea cave in the British Isles. [12] Archaeological excavations have found evidence of human habitation dating back to the Mesolithic period. [13] The cave became well known after Sir Walter Scott visited it in 1814. Another notable cave site is the Inchnadamph Bone Caves. At these caves, remains of Eurasian lynx, brown bear, Arctic fox, reindeer and polar bears have been found; as well as human remains dated between 4,515 and 4,720 years old. [14] Uamh an Claonaite, Scotland's longest cave is partly located below these Bone Caves.

Suilven, one of the park's mountains Caisteal Liath, Suilven.jpg
Suilven, one of the park's mountains

Also located in the park is Cape Wrath, the northwesternmost point on the Scottish mainland, which features the highest vertical cliffs in mainland Britain. [6] Another feature is the Old Man of Stoer, a sandstone sea stack located off the Point of Stoer in Assynt.

Mountains

The Moine Thrust Belt is regarded as the northwest boundary of the Caledonian mountain belt. [15] However, a few mountains exist within the park, some of which are well known. The highly distinctive Suilven is perhaps the most notable mountain within the park, and its image is used in promotional material. [16] Other mountains to be found here include Stac Pollaidh, Canisp, Quinag, Foinaven and Arkle.

Geology

A large boulder of Lewisian Gneiss within the geopark Lewissian Gneiss Boulder.jpg
A large boulder of Lewisian Gneiss within the geopark

The park contains a wide variety of different types of rock:

See also

Footnotes

  1. 1 2 "Scotland's first Geopark". Sustainable Tourism. VisitScotland. 18 November 2004. Archived from the original on 21 November 2008. Retrieved 27 January 2008.
  2. "Scotland's first geopark in crowdfunding bid". BBC News. 14 April 2017. Retrieved 1 July 2017.
  3. "North West Highlands Geopark: Scotland's first European Geopark" (PDF). Geopark Brochure. Archived from the original (pdf) on 27 July 2011. Retrieved 25 January 2008.
  4. "The geology of Scotland". VisitScotland website. Retrieved 26 January 2008.
  5. "Welcome to North West Highland Geopark". North West Highland Geopark Website. Retrieved 26 January 2008.
  6. 1 2 3 "The Geopark Story". North West Highlands Geopark website. Archived from the original on 27 November 2007. Retrieved 25 January 2008.
  7. "Overview of Moine Thrust". Gazetteer for Scotland . Retrieved 25 January 2008.
  8. Oldroyd, David R. (1990). The Highlands Controversy: Constructing Geological Knowledge through Fieldwork in Nineteenth-Century Britain. University of Chicago Press. ISBN   978-0-226-62634-5.
  9. Historic Environment Scotland. "Inchnadamph, Peach And Horne Memorial (286575)". Canmore . Retrieved 11 March 2022.
  10. "About Knockan Crag". Knockan Crag website. Archived from the original on 19 January 2008. Retrieved 25 January 2008.
  11. "Geology". Smoo Cave. Retrieved 25 January 2008.
  12. "Data". Smoo Cave. Retrieved 25 January 2008.
  13. "Archaeology". Smoo Cave. Retrieved 25 January 2008.
  14. "Inchnadamph Bone Caves" (pdf). Scottish Natural Heritage . Retrieved 25 January 2008.
  15. "GCR block - Moine (MOINE)". jncc.defra.gov.uk. Joint Nature Conservation Committee. Retrieved 16 April 2017.
  16. See the Geopark website and Brochure Archived 2014-08-19 at the Wayback Machine (pdf link).
  17. Lerner, K. Lee; Lerner, Brenda Wilmoth, eds. (2003). "Europe". World of Earth Science. Farmington Hills, MI: Gale. ISBN   978-0-7876-7739-8. Archived from the original on 16 September 2007. Retrieved 26 January 2008.
  18. "NWH Geology map" (PDF). British Geological Survey. Archived from the original (PDF) on 27 July 2011. Retrieved 25 January 2008.

Coordinates: 58°7′N5°8′W / 58.117°N 5.133°W / 58.117; -5.133

Related Research Articles

Thrust fault Type of reverse fault that has a dip of 45 degrees or less

A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks.

Durness Human settlement in Scotland

Durness is a village and civil parish in the north-west Highlands of Scotland. It lies on the north coast of the country in the traditional county of Sutherland, around 120 miles north of Inverness. The area is remote, and the parish is huge and sparsely populated, covering an area from east of Loch Eriboll to Cape Wrath, the most north-westerly point of the Scottish mainland.

Moine Thrust Belt

The Moine Thrust Belt or Moine Thrust Zone is a linear tectonic feature in the Scottish Highlands which runs from Loch Eriboll on the north coast 190 kilometres (120 mi) south-west to the Sleat peninsula on the Isle of Skye. The thrust belt consists of a series of thrust faults that branch off the Moine Thrust itself. Topographically, the belt marks a change from rugged, terraced mountains with steep sides sculptured from weathered igneous, sedimentary and metamorphic rocks in the west to an extensive landscape of rolling hills over a metamorphic rock base to the east. Mountains within the belt display complexly folded and faulted layers and the width of the main part of the zone varies up to 10 kilometres (6.2 mi), although it is significantly wider on Skye.

Assynt Sparsely populated area of Sutherland on the west coast of Scotland

Assynt is a sparsely populated area in the south-west of Sutherland, lying north of Ullapool on the west coast of Scotland. Assynt is known for its landscape and its remarkable mountains, which have led to the area, along with neighbouring Coigach, being designated as the Assynt-Coigach National Scenic Area, one of 40 such areas in Scotland.

Geology of Scotland Overview of geology of Scotland

The geology of Scotland is unusually varied for a country of its size, with a large number of differing geological features. There are three main geographical sub-divisions: the Highlands and Islands is a diverse area which lies to the north and west of the Highland Boundary Fault; the Central Lowlands is a rift valley mainly comprising Palaeozoic formations; and the Southern Uplands, which lie south of the Southern Uplands Fault, are largely composed of Silurian deposits.

Ben Peach

Benjamin Neeve Peach was a British geologist.

John Horne Scottish geologist

John Horne PRSE FRS FRSE FEGS LLD was a Scottish geologist. He served as President of the Royal Society of Edinburgh from 1915 to 1919.

The Northwest Highlands are located in the northern third of Scotland that is separated from the Grampian Mountains by the Great Glen. The region comprises Wester Ross, Assynt, Sutherland and part of Caithness. The Caledonian Canal, which extends from Loch Linnhe in the south-west, via Loch Ness to the Moray Firth in the north-east splits this area from the rest of the country. The city of Inverness and the town of Fort William serve as gateways to the region from the south.

Ben More Assynt

Ben More Assynt is a mountain in Assynt in the far north-west of Scotland, 30 kilometres north-northeast of Ullapool. The name translates as "big mountain of Assynt", and with a height of 998 metres it is the highest point in Sutherland.

Conival

Conival is a Scottish mountain situated in Assynt in the Sutherland area of the Highland Council Area, thirty kilometres north-northeast of Ullapool.

Loch Assynt A lake in Sutherland, Scotland

Loch Assynt is a freshwater loch in Sutherland, Scotland, 8 kilometres (5.0 mi) east-north east of Lochinver.

Inchnadamph Human settlement in Scotland

Inchnadamph is a hamlet in Assynt, Sutherland, Scotland. The name is an anglicisation of the Gaelic name Innis nan Damh meaning 'meadow of the stags'. Assynt is a remote area with a low population density. Inchnadamph contains a few houses, a lodge, a hotel and a historic old church, graveyard and mausoleum.

Knockan Crag

Knockan Crag lies within the North West Highlands Geopark in the Assynt region of Scotland 21 kilometres (13 mi) north of Ullapool. During the nineteenth century Knockan Crag became the subject of much debate when geologists noted 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. Disagreements over the processes that could have caused this to occur were referred to at the time as the "Highlands Controversy". The argument was primarily between Roderick Murchison and Archibald Geikie on the one hand and James Nicol and Charles Lapworth on the other. Murchison and Geikie believed the sequence was wrong and that the Moine schists must be the younger rocks. The controversy was finally resolved by the work of Ben Peach and John Horne whose 1907 paper on the subject remains a classic text. Peach and Horne demonstrated that the situation resulted from 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.

Stac Fada Member

The Stac Fada Member is a distinctive layer towards the top of the Mesoproterozoic Bay of Stoer Formation, part of the Stoer Group in northwest Scotland. This rock unit is generally 10 to 15 metres thick and is made of sandstone that contains accretionary lapilli and many dark green glassy fragments of mafic composition.

Loch Alsh A sea loch on the West Coast of Scotland

Loch Alsh is a sea inlet between the isle of Skye in the Inner Hebrides and the Northwest Highlands of Scotland. The name is also used to describe the surrounding country and the feudal holdings around the loch. The area is rich in history, and is increasingly popular with tourists.

Moine Supergroup

The Moine Supergroup is a sequence of Neoproterozoic metamorphic rocks that form the dominant outcrop of the Scottish Highlands between the Moine Thrust Belt to the northwest and the Great Glen Fault to the southeast. The sequence is metasedimentary in nature and was metamorphosed and deformed in a series of tectonic events during the Late Proterozoic and Early Paleozoic. It takes its name from A' Mhòine, a peat bog in northern Sutherland.

Lewisian complex

The Lewisian complex or Lewisian gneiss is a suite of Precambrian metamorphic rocks that outcrop in the northwestern part of Scotland, forming part of the Hebridean Terrane and the North Atlantic Craton. These rocks are of Archaean and Paleoproterozoic age, ranging from 3.0–1.7 billion years (Ga). They form the basement on which the Torridonian and Moine Supergroup sediments were deposited. The Lewisian consists mainly of granitic gneisses with a minor amount of supracrustal rocks. Rocks of the Lewisian complex were caught up in the Caledonian orogeny, appearing in the hanging walls of many of the thrust faults formed during the late stages of this tectonic event.

Hebridean Terrane Part of the Caledonian orogenic belt in northwest Scotland

The Hebridean Terrane is one of the terranes that form part of the Caledonian orogenic belt in northwest Scotland. Its boundary with the neighbouring Northern Highland Terrane is formed by the Moine Thrust Belt. The basement is formed by Archaean and Paleoproterozoic gneisses of the Lewisian complex, unconformably overlain by the Neoproterozoic Torridonian sediments, which in turn are unconformably overlain by a sequence of Cambro–Ordovician sediments. It formed part of the Laurentian foreland during the Caledonian continental collision.

Highlands controversy of Northwest Scotland 19th-century geological controversy

The Highlands controversy was a scientific controversy which started between British geologists in the middle of the nineteenth century concerning the nature of the rock strata in the Northwest Highlands of Scotland. The debate became contentious, even acrimonious, because of some of the personalities involved and because it pitted professional geologists of the Geological Survey against academic and amateur geologists. An initial resolution was achieved by about 1886 but the great complexity and scientific importance of the discovery of the Moine Thrust Belt and the geological processes involved in its creation led to field work continuing for a further twenty years culminating in the 1907 publication by the Geological Survey of a book of fundamental geological significance: The Geological Structure of the North-West Highlands of Scotland.

The geology of national parks in Britain strongly influences the landscape character of each of the fifteen such areas which have been designated. There are ten national parks in England, three in Wales and two in Scotland. Ten of these were established in England and Wales in the 1950s under the provisions of the National Parks and Access to the Countryside Act 1949. With one exception, all of these first ten, together with the two Scottish parks were centred on upland or coastal areas formed from Palaeozoic rocks. The exception is the North York Moors National Park which is formed from sedimentary rocks of Jurassic age.