- Geology of Scotland
The geology of Scotland is unusually varied for a country of its size, with a large number of differing geological features. [Keay & Keay (1994) "op cit" page 415.] There are three main geographical sub-divisions: the
Highlands and Islands is a diverse area which lies to the north and west of theHighland Boundary Fault ; theCentral Lowlands is arift valley mainly comprisingPaleozoic formations; and theSouthern Uplands , which lie south of a second fault line, are largely composed ofSilurian deposits.The existing bedrock includes very ancient
Archean gneiss , metamorphic beds interspersed withgranite intrusions created during the Caledonian mountain building period (theCaledonian orogeny ), commercially importantcoal ,oil andiron bearingcarboniferous deposits and the remains of substantialtertiary volcano es. During their formation, tectonic movements created climatic conditions ranging from polar to desert to tropical and a resultant diversity offossil remains.Scotland has also had a role to play in many significant discoveries such as
plate tectonics and the development of theories about the formation of rocks and was the home of important figures in the development of the science includingJames Hutton , (the "father of modern geology") [ [http://www.ed.ac.uk/explore/people/plaques/jameshutton.html University of Edinburgh - James Hutton] Retrieved 16 August 2007.]Hugh Miller andArchibald Geikie .Keay & Keay (1994) "op cit" pages 415-422.] Various locations such as 'Hutton's Unconformity' atSiccar Point in Berwickshire and the Moine Thrust in the north west were also important in the development of geological science.Overview
From a geological and geomorphological perspective the country has three main sub-divisions all of which were affected by
Pleistocene glaciations.Highlands and Islands
The Highlands and Islands lie to the north and west of the Highland Boundary Fault, which runs from Arran to
Stonehaven . This part of Scotland largely comprises ancient rocks, from theCambrian andPrecambrian eras, that were uplifted to form a mountain chain during the later Caledonianorogeny . These foundations are interspersed with many igneous intrusions of a more recent age, the remnants of which have formed mountain massifs such as theCairngorms andSkye Cuillins . A significant exception to the above are the fossil-bearing beds ofOld Red Sandstone s found principally along theMoray Firth coast and in the Orkney islands. These rocks are around 400 million years old, and were laid down in theDevonian period. [McKirdy et al (2007) "op cit" pages 124-31.] The Highlands are generally mountainous and are bisected by theGreat Glen Fault. The highest elevations in theBritish Isles are found here, includingBen Nevis , the highest peak at 1,344 metres (4,409 ft). Scotland has over 790 islands, divided into four main groups: Shetland, Orkney, and theHebrides , further sub-divided into theInner Hebrides andOuter Hebrides .The Hebridean archipelago outlier of St Kilda is composed of
Tertiary igneous formations ofgranites and gabbro, heavily weathered by the elements. These islands represent the remnants of a long extinct ring volcano rising from a seabed plateau approximately 40 m (130 ft) below sea level. [ [http://www.snh.org.uk/pdfs/trends/seas/Seas_Part1.pdf SNH Trends- seas] (PDF) Retrieved 2 January 2007.]The geology of Shetland is complex with numerous faults and fold axes. These islands are the northern outpost of the
Caledonian orogeny and there are outcrops of Lewisian, Dalriadan and Moine metamorphic rocks with similar histories to their equivalents on the Scottish mainland. Similarly, there are alsoOld Red Sandstone deposits andgranite intrusions. The most distinctive feature is the ultrabasic ophioliteperidotite andgabbro onUnst andFetlar , which are remnants of theIapetus Ocean floor. [ Gillen, Con (2003) "op cit". Pages 90-1.] Much of Shetland's economy depends on the oil-bearing sediments in the surrounding seas. [Keay & Keay (1994) "op cit" page 867.]Midland Valley
Often referred to as the
Central Lowlands , this is a rift valley mainly comprisingPaleozoic formations. Many of these sediments have economic significance for it is here that the coal and iron bearing rocks that fuelled Scotland'sindustrial revolution are to be found. This area has also experienced intense vulcanism, Arthur’s Seat inEdinburgh being the remnant of a once much largervolcano active in theCarboniferous period some 300 million years ago. This area is relatively low-lying, although even here hills such as the Ochils andCampsie Fells are rarely far from view.outhern Uplands
The
Southern Uplands are a range of hills almost 200 km (125 miles) long, interspersed with broad valleys. They lie south of a second fault line running from theRhinns of Galloway towardsDunbar . The geological foundations largely compriseSilurian deposits laid down some 4-500 million years ago. [ [http://www.geo.edinburgh.ac.uk/scotgaz/features/featurefirst7744.html "Southern Uplands Fault"] Gazetteer for Scotland. Retrieved 11 January 2008.] [ [http://www.scottishgeology.com/geology/regional_geology/geo_maps/southern_uplands_map.html "Regional Geology, Southern Uplands - Map"] Scottishgeology.com. Retrieved 21 March 2008.]Post-glacial events
The whole of Scotland was covered by ice sheets during the
Pleistocene ice ages and the landscape is much affected byglaciation , and to a lesser extent by subsequent sea level changes. [Murray, W.H. (1973) "The Islands of Western Scotland". London. Eyre Methuen.] [Murray, W.H. (1977) "The Companion Guide to the West Highlands of Scotland". London. Collins.] In the post-glacial epoch, circa 6100 BC, Scotland and theFaeroe Islands experienced atsunami up to 20 metres high caused by theStoregga Slide s, an immense underwater landslip off the coast of Norway. [ [http://www.spiegel.de/international/0,1518,441819,00.html "Study Sees North Sea Tsunami Risk"] Speigel Online. Retrieved 28 July 2007.] [Bondevik, Stein; Dawson, Sue; Dawson, Alastair; Lohne, Øystein. (5 August 2003) [http://www.ibg.uit.no/~stein/Bondevik-al-03-EOS.pdf "Record-breaking Height for 8000-Year-Old Tsunami in the North Atlantic"] (pdf) EOS, Transactions of the American Geophysical Union. Vol.84 Issue 31, pages 289-293. Retrieved 15 January 2007.] Earth tremors are infrequent and usually slight. The Great Glen is the most seismically active area of Britain, but the last event of any size was in 1901. [ [http://www.invernessroyal.highland.sch.uk/resources/earthquakes.html#1816 "Earthquakes in the Inverness Area"] Inverness Royal Academy. Retrieved 8 November 2007.]Chronology
Archean and Proterozoic eras
The oldest rocks of Scotland are the
Lewis iangneiss es, which were laid down in thePrecambrian period, up to 3,000 million years ago (mya). They are the oldest in Europe and amongst the oldest rocks in the world. They form basement deposits to the west of the Moine Thrust on the mainland, in theOuter Hebrides and on the islands ofColl andTiree . [ Gillen (2003) "op cit" page 44.] These rocks are largely igneous in origin, mixed with metamorphosedmarble ,quartzite andmica schist and intruded by later basaltic dykes and granite magma. [McKirdy et al (2007) "op cit" page 95.] One of these intrusions forms the summit plateau of the mountain Roinebhal inHarris . The granite here isanorthosite , and is similar in composition to rocks found in the mountains of theMoon . [ McKirdy et al (2007) "op cit" page 94.] Torridonian sandstones were also laid down in this period over the gneisses, and these contain the oldest signs of life in Scotland. In later Precambrian times, thick sediments of sandstones,limestone s muds andlava s were deposited in what is now the Highlands of Scotland. [ McKirdy et al (2007) "op cit" page 68.] [ [http://www.geologyrocks.co.uk/tut.php?tutorial=16 "Precambrian History of the UK"] geologyrocks.co.uk. Retrieved 1 August 2007.]Paleozoic era
Cambrian period
Further
sedimentary deposits were formed through theCambrian period, (542-488 mya) some of which, along with the earlier Precambrian sediments, metamorphosed into theDalradian series. This is composed of a wide variety of materials, including mica schist,biotite gneiss schist,schistose grit,greywacke andquartzite . [Sellar, W.D.H. (ed) (1993) "Moray: Province and People." The Scottish Society for Northern Studies.] The area that would become Scotland was at this time close to the south pole and part ofLaurentia . Fossils from the north-west Highlands indicate the presence oftrilobite s and other primitive forms of life. [ McKirdy et al (2007) "op cit" page 68.] [ [http://www.geologyrocks.co.uk/tut.php?tutorial=17 "Palaeozoic History of the UK: Cambrian to Silurian"] geologyrocks.co.uk. Retrieved 1 August 2007.]Ordovician period
The proto-Scotland landmass moved northwards and from 460-430 mya
sandstone ,mudstone andlimestone was deposited in the area that is now the Midland Valley. This occurred in shallow tropical seas at the margins of theIapetus Ocean . The Ballantrae Complex nearGirvan was formed from this ocean floor and is similar in composition to rocks found atThe Lizard inCornwall . Nonetheless, northern and southern Britain were far apart at the beginning of this period, although the gap began to close as the continent ofAvalonia broke away fromGondwana , collided withBaltica and drifted towards Laurentia. TheCaledonian orogeny began forming a mountain chain from Norway to theAppalachians . There was an ice age in the southern hemisphere, and the first mass extinction of life on Earth took place at the end of this period. [Gillen (2003) "op cit" pages 98 and 111.] [ McKirdy et al (2007) "op cit" page 68.]ilurian period
During the
Silurian period (443-416 mya) the continent ofLaurentia gradually collided with Baltica, joining Scotland to the area that would become England and Europe. Sea levels rose as theOrdovician ice sheets melted, and tectonic movements created major faults which assembled the outline of Scotland from previously scattered fragments. These faults are theHighland Boundary Fault , separating the Lowlands from the Highlands, theGreat Glen Fault that divides the North-west Highlands from the Grampians, the Southern Uplands Fault and theIapetus Suture , which runs from theSolway Firth toLindisfarne and which marks the close of theIapetus Ocean and the joining of northern and southern Britain. [Gillen (2003) "op cit" pages 69, 73, 75, 88 and 95.] [ McKirdy et al (2007) "op cit" page 68.] [ [http://www.geologyrocks.co.uk/tut.php?tutorial=17 "Palaeozoic History of the UK: Cambrian to Silurian"] Retrieved 1 August 2007.]Silurian rocks form the
Southern Uplands of Scotland, which were pushed up from the sea bed during the collision with Baltica/Avalonia. The majority of the rocks are weakly metamorphosed coarsegreywacke . [Gillen (2003) "op cit" page 95.] The Highlands were also affected by these collisions, creating a series ofthrust fault s in the northwest Highlands including the Moine Thrust, the understanding of which played an important role in nineteenth century geological thinking. Volcanic activity occurred across Scotland as a result of the collision of thetectonic plate s, withvolcano es in southern Scotland, andmagma chamber s in the north, which today form thegranite mountains such as theCairngorms . [http://earth.leeds.ac.uk/mtb/ Butler, Rob (2000) "The Moine Thrust Belt". Leeds University.] Retrieved 27 January 2006.]Devonian period
The Scottish landmass now formed part of the Old Red Sandstone Continent and lay some 25 degrees south of the equator, moving slowly north during this period to 10 degrees south. The accumulations of
Old Red Sandstone laid down from 408 to 370 million years ago were created as earlierSilurian rocks, uplifted by the formation ofPangaea , eroded and were deposited into a body of freshwater (probably a series of large river deltas). A huge freshwater lake - the Orcadian Lake - existed on the edges of the eroding mountains stretching from Shetland to the southern Moray Firth. The formations are extremely thick, up to 11,000 meters in places, and can be subdivided into three categories "Lower", "Middle", and "Upper" from oldest to youngest. As a result, the Old Red Sandstone is an important source of fishfossils and it was the object of intense geological studies in the 1800s. In Scotland these rocks are found predominantly in the Moray Firth basin and Orkney Archipelago, and along the southern margins of the Highland Boundary Fault.Elsewhere volcanic activity, possibly as a result of the closing of the Iapetus Suture, created the
Cheviot Hills ,Ochil Hills ,Sidlaw Hills , parts of thePentland Hills and Scurdie Ness on theAngus coast. [ [http://www.scottishgeology.com/geology/geological_time_scale/timeline/devonian.htm "The Devonian Period (416 ~ 359 million years ago)"] Scottishgeology.com. Retrieved 15 August 2007.] [Gillen (2003) "op cit" pages 110-119.] [ McKirdy et al (2007) "op cit" pages 124-130.]Carboniferous period
During the
Carboniferous period (359-299 mya), Scotland lay close to the equator. Several changes in sea level occurred and thecoal deposits ofLanarkshire andWest Lothian and limestones ofFife andDunbar date from this time. There are oil shales nearBathgate around which the nineteenth century oil-processing industry developed, and elsewhere in the Midland Valley there are ironstones and fire clay deposits that had significance in the earlyIndustrial Revolution . Fossil Grove inVictoria Park, Glasgow contains the preserved remains of a Carboniferous forest. More volcanic activity formed Arthur's Seat and theSalisbury Crags inEdinburgh and the nearby Bathgate Hills. [McKirdy et al (2007) "op cit" pages 132-135.] [Gillen, Con (2003) "op cit". Pages 120-5.]Permian period
The Old Red Sandstone Continent became a part of the supercontinent
Pangaea in thePermian (299-251 mya), during which proto-Britain continued to drift northwards. Scotland's climate was arid at this time and some fossils of reptiles have been recovered. However, Permian sandstones are found in only a few places - principally in the south west, on the island of Arran, and on the Moray coast. Stone quarried fromHopeman in Moray has been used in the National Museum andScottish Parliament building s in Edinburgh. [McKirdy et al (2007) "op cit" pages 141-144.]At the close of this period came the
Permian–Triassic extinction event in which 96% of all marinespecies vanishedcite book|author=Benton M J|date=2005|title=When Life Nearly Died: The Greatest Mass Extinction of All Time|publisher=Thames & Hudson|isbn=978-0500285732] and from which bio-diversity took 30 million years to recover.Mesozoic era
Triassic period
During the
Triassic , (251-200 mya) much of Scotland remained in desert conditions, with higher ground in the Highlands and Southern Uplands providing sediment to the surrounding basins via flash floods. This is the origin of sandstone outcrops nearDumfries , Elgin and theIsle of Arran . Towards the close of this period sea levels began to rise and climatic conditions became less arid. [ [http://www.scottishgeology.com/geology/geological_time_scale/timeline/permian.htm "The Permian & Triassic Periods (299 ~251 and 251 ~ 200 million years ago respectively)"] Scottishgeology.com. Retrieved 31 July 2007.]Jurassic period
As the
Jurassic (200-145 mya) started,Pangaea began to break up into twocontinents ,Gondwana andLaurasia , marking the beginning of the separation of Scotland and North America. Sea levels rose, as Britain and Ireland drifted on theEurasian Plate to between 30° and 40° north. Most of northern and eastern Scotland including Orkney, Shetland and the Outer Hebrides remained above the advancing seas, but the south and south-west were inundated. There are only isolatedsedimentary rock s remaining on land from this period, on theSutherland coast near Golspie and on Skye, Mull,Raasay andEigg . This period does however have considerable significance.The burial ofalgae and bacteria below the mud of the sea floor during this time resulted in the formation ofNorth Sea oil andnatural gas , much of it trapped in overlying sandstone by deposits formed as the seas fell to form the swamps and salty lakes and lagoons that were home todinosaur s. [McKirdy et al (2007) "op cit" page 146.] [ Gillen, Con (2003) "op cit" Pages 133-7.]Cretaceous period
In the
Cretaceous , (146-65 mya) Laurasia split into the continents of North America andEurasia . Sea levels rose globally during this period and much of low-lying Scotland was covered in a layer ofchalk . Although large deposits ofCretaceous rocks were laid down over Scotland, these have not survived erosion except in a few places on the west coast such asLoch Aline inMorvern . [Gillen (2003) "op cit" pages 138-9.] [ [http://www.scottishgeology.com/geology/geological_time_scale/timeline/cretaceous.htm "The Cretaceous Period (146 ~ 65 million years ago)"] Scottish geology.com. Retrieved 16 August 2007.] At the end of this period theCretaceous–Tertiary extinction event brought the age of dinosaurs to a close.Cenozoic era
Paleogene period
In the early
Paleogene period between 63 and 52 mya, the last volcanic rocks in the British Isles were formed. As North America andGreenland , separated from Europe the Atlantic Ocean slowly formed. This led to a chain of volcanic sites west of mainland Scotland including on Skye, theSmall Isles and St. Kilda, in theFirth of Clyde on Arran andAilsa Craig and atArdnamurchan . [Gillen (2003) "op cit" page 142.] Sea levels began to fall, and for the first time the general outline of the modern British Isles was revealed. [ McKirdy et al (2007) "op cit" page 150.] At the beginning of this period the climate was sub-tropical and erosion was caused by chemical weathering, creating characteristic features of the Scottish landscape such as the topographical basin of the Howe of Alford near Aberdeen. [ McKirdy et al (2007) "op cit" page 158.] By 35 mya the landscape includedbeech ,oak ,chestnut and sycamore trees, along withgrass land.Neogene period
Miocene and Pliocene epochs
In the
Miocene andPliocene epochs further uplift and erosion occurred in the Highlands. Plant and animal types developed into their modern forms, and by about 2 million years ago the landscape would have been broadly recognisable today, with Scotland lying in its present position on the globe. As the Miocene progressed, temperatures dropped and remained similar to today's. [ McKirdy et al (2007) "op cit" page 158.] [ [http://www.fettes.com/Cairngorms/tertiary.htm "Tertiary"] Fettes.com Retrieved 16 August 2007.]Pleistocene epoch
Several
ice age s shaped the land through glacial erosion, creating u-shaped valleys and depositingboulder clay s, especially on the western seaboard. The last major incursion of ice peaked about 18,000 years ago, leaving other remnant features such at the granitetor s on the Cairngorm Mountain plateaux. [ McKirdy et al (2007) "op cit" pages 159 and 163-171.] [ [http://www.scottishgeology.com/geology/geological_time_scale/timeline/quaternary.htm "The Quaternary"] Scottishgeology.com. Retrieved 16 August 2007.]Holocene epoch
Over the last twelve thousand years the most significant new geological features have been the deposits of
peat and the development of coastal alluvium. Post-glacial rises in sea level have been combined with isostatic rises of the land resulting in a relative fall in sea level in most areas. [ [http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=87 "Update to UKCIP02 sea level change estimates"] (December 2005) UK Climate Impacts Programme. Retrieved 10 June 2008.] [ Smith, David E., and Fretwell, Peter T. [http://www.scottishsealevels.net/scottish-sea-level-change.htm "Scottish Sea Levels"] scottishsealevels.net. Retrieved 15 November 2007.] In some places, such as Culbin in Moray, these changes in relative sea level have created a complex series of shorelines. [Ross, Sinclair (1992) "The Culbin Sands – Fact and Fiction". Aberdeen University Press.] About half of thecoastline of Scotland consists of machairhabitat , [cite web|url=http://www.wildlifehebrides.com/environment/machair/| publisher = wildlifehebrides.com | title="The Natural Environment: Machair" | accessdate = 2007-10-03] a low lying dune pasture land formed as the sea level dropped leaving a raised beach. In the present day, Scotland continues to move slowly north.Geologists in Scotland
Scottish geologists and non-Scots working in Scotland have played an important part in the development of the science, especially during its pioneering period in the late eighteenth and nineteenth centuries. [Keay & Keay (1994) "op cit" page 415.]
*James Hutton (1726-1797) the "father of modern geology" was born in Edinburgh. His "Theory of the Earth", published in 1788 proposed the idea of a rock cycle in which weathered rocks form new sediments and that granites were of volcanic origin. AtGlen Tilt in the Cairngorm mountains he foundgranite penetrating metamorphicschist s. This showed to him that granite formed from the cooling of molten rock, not precipitation out of water as the Neptunists of the time believed.cite web |url= http://findarticles.com/p/articles/mi_qa3724/is_200309/ai_n9253355 |title= Glimpses into the abyss of time |author= Robert Macfarlane |format=html |work=The Spectator |publisher= Review of Repcheck's "The Man Who Found Time" |date= 13 September 2003] This sight is said to have "filled him with delight". [Keay & Keay (1994) "op cit" page 531.] Regarding geological time scales he famously remarked "that we find no vestige of a beginning, no prospect of an end." [McKirdy et al (2007) "op cit" pages 61 and 115.]
*John Playfair (1748-1819) fromAngus was a mathematician who developed an interest in geology through his friendship with Hutton. His 1802 "Illustrations of the Huttonian Theory of the Earth" were influential in the latter's success. ["Biographical Dictionary of Eminent Scotsmen" (1856), reproduced in [http://www.electricscotland.com/history/other/playfair_john.htm "Significant Scots"] electricscotland.com. Retrieved 3 October 2007.]
*John MacCulloch (1773-1835) was born inGuernsey and like Hutton before him, studied medicine atEdinburgh University . A president of the Geological Society from 1815-17, he is best remembered for producing the first geological map of Scotland, published in 1836. 'Macculloch's Tree ', a convert|40|ft|m|sing=on high fossil conifer in the Mull lava flows, is named after him. [McKirdy et al (2007) "op cit" page 156.] Jones (1997) "op cit". Page 38.]*Sir Charles Lyell (1797-1875) was also from Angus and his "
Principles of Geology " built on Hutton's ideas. Lyell's theory of uniformitarianism and his interpretation of geologic change as the steady accumulation of minute changes over enormously long spans of time was a central theme in the "Principles", and a powerful influence on the youngCharles Darwin . (Robert FitzRoy , captain of HMS "Beagle", loaned Darwin a copy of Volume 1 of the first edition just before they set out on the 'Voyage of the Beagle'.) Lyell is buried inWestminster Abbey . [Keay & Keay (1994) "op cit" page 641.] [ [http://www.british-history.ac.uk/report.asp?compid=45165 "Westminster Abbey.—A Survey of the Building."] British History Online. Retrieved 12 August 2007] [ [http://www.aboutdarwin.com/people/people_01.html#0145 "Lyell, Sir Charles [1797 - 1875] " About Darwin.com. Retrieved 12 August 2007.]* Sir Roderick Murchison (1792–1871) was born in Ross and Cromarty and served under Wellesley in the
Peninsular War . Knighted in 1846, his main achievements were the investigation ofSilurian rocks published as "The Silurian System" in 1839 and ofPermian deposits in Russia. The Murchison crater on theMoon and at least fifteen geographical locations on Earth are named after him. [Morton, John L. (2004) "King of Siluria — How Roderick Murchison Changed the Face of Geology". Horsham. Brocken Spectre. ISBN 0954682904.] [Keay & Keay (1994) "op cit" page 717.]
*Hugh Miller (1802-56) fromCromarty was a stonemason and self-taught geologist. His 1841 publication "The Old Red Sandstone" became a bestseller. The fossils founds in these rocks were one of his fascinations, although his deep religious convictions led him to oppose the idea of biological evolution. [ [http://www.hughmiller.org/who_was_hugh_g.asp "Who Was He, Then?"] Discover Hugh Miller. Retrieved 8 July 2007.]
*James Croll (1821-90) developed a theory ofclimate change based on changes in the earth's orbit. Born near Perth, he was self-educated and his interest in science led to his becoming appointed as a janitor in the museum at theAndersonian College and Museum , Glasgow in 1859. His 1864 paper "On the Physical Cause of the Changes of Climate during Glacial Epochs" led to a position in theEdinburgh office of the Geological Survey of Scotland, as keeper of maps and correspondence, where SirArchibald Geikie , encouraged his research. He was eventually to become a Fellow of theRoyal Society . [McKirdy et al (2007) "op cit" page 77.]
*Sir Archibald Geikie (1835-1924) was the first to recognise that there had been multiple glaciations, and his 1863 paper "On the glacial drift of Scotland" was a landmark in the emergent theories ofglaciation . He became Director-General of the Geological Survey of the United Kingdom in 1888 and was also well-known for his work onvulcanism . [McKirdy et al (2007) "op cit" page 86.]
*Arthur Holmes (1890-1965) was born in England and became Regius Professor of Geology at theUniversity of Edinburgh in 1943. His "magnum opus" was "Principles of Physical Geology", first published in 1944, in which he proposed the idea that slow moving convention currents in the Earth's mantle created 'continental drift' as it was then called. He also pioneered the discipline ofgeochronology . He lived long enough to see the theory ofplate tectonics become widely accepted, and he is regarded as one of the most influential geologists of the 20th century. [ McKirdy et al (2007) "op cit" page 54.]Important sites
*
Siccar Point ,Berwickshire is world famous as one of the sites that proved Hutton's views about the immense age of the Earth. Here Silurian rocks have been tilted almost to the vertical. Younger Devonian rocks lie unconformably over the top of them, dipping gently, indicating that an enormous span of time must have passed between the creation of the two beds. When Hutton and James Hall visited the site in 1788 their companion Playfair wrote: [McKirdy et al (2007) "op cit" page 253.] [Gillen (2003) "op cit" page 95.] Quote box
width=60%
align=centre
quote=On us who saw these phenomenon for the first time the impression will not easily be forgotten...We felt necessarily carried back to a time when the schistus on which we stood was yet at the bottom of the sea, and when the sandstone before us was only beginning to be deposited, in the shape of sand or mud, from the waters of the supercontinent ocean... The mind seemed to grow giddy by looking so far back into the abyss of time; and whilst we listened with earnestness and admiration to the philosopher who was now unfolding to us the order and series of these wonderful events, we became sensible how much further reason may sometimes go than imagination may venture to follow.|source=John Playfair (1805) Transactions of theRoyal Society of Edinburgh , vol. V, pt. III. [cite web |url= http://findarticles.com/p/articles/mi_m1134/is_5_108/ai_54830705 |title= Hutton's Unconformity |author=John Playfair |format=html |work= Transactions of theRoyal Society of Edinburgh , vol. V, pt. III, 1805, quoted in Natural History, June 1999]
* The Moine Thrust inAssynt is one of the most studied geological features in the world. Its discovery in the 1880s was a milestone in the history of geology as it was one of the first thrust belts in the world to be identified. Investigations byJohn Horne and Benjamin Peach resolved a dispute between Murchison and Geikie on the one hand and James Nicol andCharles Lapworth on the other. The latter believed that older Moine rocks lay on top of younger Cambrian rocks atKnockan Crag , and Horne and Peach's work confirmed this in their classic paper "The Geological Structure of the Northwest Highlands of Scotland", which was published in 1907. [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.] [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.] A statue to these two pioneers of fieldwork was erected atInchnadamph near the hotel there which played a prominent part in the annals of early geology. [McKirdy et al (2007) "op cit" pages 110 and 121-122.] This area is at the heart of the 'North West Highlands Geopark'. [ [http://www.northwest-highlands-geopark.org.uk/ "Welcome to North West Highland Geopark] northwest-highlands-geopark.org.uk. Retrieved 18 August 2007.]
* Lapworth also had a prominent role to play in the fame ofDob's Linn , a small gorge in theScottish Borders , which contains the 'golden spike' (i.e. the official international boundary or stratotype) between the Ordovician and Silurian periods. Lapworth's work in this area, especially his examination of the complexstratigraphy of the Silurian rocks by comparing fossilgraptolite s, was crucial in to the early understanding of these epochs.* The Skye
Cuillin mountains provide classic examples of glacial topography and were the subject of an early published account by James Forbes in 1846 (who had become a fellow of theRoyal Society of Edinburgh aged only nineteen). [cite web|url=http://www.1911encyclopedia.org/James_David_Forbes| title = "James David Forbes" | publisher=1911encyclopedia.org | accessdate = 2007-10-03] [Forbes, James D. (1846) "Notes on the topography and geology of Cuchullin Hills in Skye, and on traces of ancient glaciers which they present". Edinburgh New Philosophical Journal No. 40. Pages 76-99.] He partneredLouis Agassiz on his trip to Scotland in 1840 and although they subsequently argued, Forbes went on to publish other important papers on Alpine glaciers. [Forbes, James D. (1846) "On the Viscous Theory of Glacier Motion" Abstracts of the Papers Communicated to the Royal Society of London, Vol. 5, 1843 - 1850. Pages 595-596.]
* In 1904Alfred Harker published "The Tertiary Igneous Rocks of Skye", the first detailed scientific study of an extinct volcano. [McKirdy et al (2007) "op cit" pages 164-5 and 280.] [Harker, Alfred, (1904) "The Tertiary Igneous Rocks of Skye". Geological Survey of Scotland Memoir.]
* In the hills to the north of the village ofStrontian the mineralstrontianite was discovered, from which the elementstrontium was first isolated by SirHumphry Davy in 1808. [ [http://www.undiscoveredscotland.co.uk/strontian/strontian/ "Strontian"] Undiscovered Scotland. Retrieved 8 July 2007.] [ [http://www.rock-site.co.uk/Pages/Strontian/Strontian.html "History and Minerals of Strontian mines"] rock-site.co.uk. Retrieved 8 July 2007.]
* The island ofStaffa , containsFingal's Cave made up of massive rectangular columns ofTertiary basalt and Mackinnon's Cave, one of the longest sea caves in the world. [ [http://www.caverbob.com/seacave.html "Long Sea Caves of the World"] caverbob.com. Retrieved 14 April 2007. Note however that the list only features entries from North America, Hawaii, and Europe.]
* TheMunro Schiehallion 's isolated position and regular shape ledNevil Maskelyne to use the deflection caused by themass of the mountain to estimate the mass of theEarth in a ground-breaking experiment carried out in 1774. Following Maskelyne's survey, Schiehallion became the first mountain to be mapped usingcontour line s. [ [http://adsabs.harvard.edu/full/1985QJRAS..26..289D Davies, R.D. (1985) "A Commemoration of Maskelyne at Schiehallion". Royal Astronomical Society Quarterly Journal. Vol. 26 No.3] Retrieved 8 July 2007.]
* The village ofRhynie inAberdeenshire is the site of an important sedimentary deposit -Rhynie chert . The bulk of this fossil bed consists of primitiveplant s that had water-conducting cells and sporangia but no leaves, along witharthropod s:Collembola ,Opiliones (harvestmen),pseudoscorpion s and the extinct, spider-likeTrigonotarbid s. This fossil bed is remarkable for two reasons. Firstly, the age of the find (early Devonian circa 410 mya) [Rice, C. M., Ashcroft, W. A., Batten, D. J., Boyce, A. J., Caulfield, J. B. D., Fallick, A. E., Hole, M. J., Jones, E., Pearson, M. J., Rogers, G., Saxton, J. M., Stuart, F. M., Trewin, N. H. & Turner, G. (1995) "A Devonian auriferous hot spring system, Rhynie, Scotland". Journal of the Geological Society, London, 152. Pages 229-250.] [ [http://www.bgs.ac.uk/nigl/pdf_downloads/2004AnnualReport.pdf "Absolute age and underlying cause of hot-spring activity at Rhynie, NE Scotland from high precision geo-chronology"] (pdf) "NIGL Annual Report for 2003-4". Annex 7: Scientific highlights for the 2003-2004 year. p. 42.] makes this one of the earliest sites anywhere containing terrestrial fossils, coinciding with the first stages of the colonisation of land by plants andanimal s. Secondly, thesechert s are famous for their exceptional state of ultrastructural preservation, with individual cell walls easily visible in polished specimens. For example,stomata have been counted andlignin remnants detected in the plant material.
* A disused quarry atEast Kirkton in the Bathgate Hills is the location where the Carboniferous fossil of "Westlothiana lizziae" (aka 'Lizzie') was found in 1984. This lizard is one of the earliest known ancestors of thereptile s. The specimen was purchased in part by public subscription and is now on display in theNational Museum of Scotland . The site was originally discovered in the early nineteenth century and has also provided fossileurypterid s,shark s and a variety of primitiveacanthodian fish. [McKirdy et al (2007) "op cit" page 132.]
* In 2008 the ejected material from ameteorite impact crater was discovered near Ullapool in Wester Ross. Preserved within sedimentary layers of sandstone, this is the largest knownbolide impact from what are now theBritish Isles . [ Amor, Kenneth; Hesselbo, Stephen P.; Porcelli, Don; Thackrey, Scott; and Parnell, John (April 2008) [http://www.gsajournals.org/perlserv/?request=get-document&doi=10.1130%2FG24454A.1 "A Precambrian proximal ejecta blanket from Scotland"] "Geological Society of America". Volume 36:4 pp. 303–306.]ee also
*
Geography of Scotland
*
*
*Geology of the British Isles :*Geology of Ireland :*Geology of England :*Geology of Wales
*British Geological Survey
*Geologic timescale
*Coal Measures
*Old Red Sandstone
*New Red Sandstone References
General references:
* Gillen, Con (2003) "Geology and landscapes of Scotland". Harpenden. Terra Publishing.
* Jones, Rosalind (1997) "Mull in the Making". Aros. R Jones. ISBN 0953189007
* Keay, J. & Keay, J. (1994) "Collins Encyclopaedia of Scotland". London. HarperCollins.
* McKirdy, Alan Gordon, John & Crofts, Roger (2007) "Land of Mountain and Flood: The Geology and Landforms of Scotland". Edinburgh. Birlinn.
* [http://www.scottishgeology.com "Scottish Geology"] Scottishgeology.com. Retrieved 30 September 2007.Footnotes
External links
* [http://www.scottishgeology.com Scottish Geology.com]
Wikimedia Foundation. 2010.