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The Royal Society of EdinburghRSE @ Lochaber

Scotland Rocks!

Professor Iain Stewart MBE

Monday 17 J une 2013, Ben Nevis Hotel, Fort William

Report by Kate Kennedy

Iain Stewart examined the remarkable geological heritage of Scotland and exploredhow we protect this magnificent legacy and how best we communicate theimportance of the rocks beneath our feet to fellow Scots.

Professor Stewart has a fundamental interest in reaching out the general public andtrying to stimulate their interest in geology. He stresses that his numerous televisionprogrammes on the subject, however, are entertainment not education but if peopleare educated through them thats a bonus! He considers that Scotlands rocks areimportant and should be treasured.

J ames Hutton FRSE, the Father of Modern Geology, was a farmers son from nearEdinburgh. Writing at the time of the Scottish Enlightenment, his 1788 paper, Theoryof the Earth, clarified some of the fundamental principles of geology and establishedthe subject as a proper science. Through careful observation of Scottish geology, herealised the importance of the Earths internal heat to the perpetual formation of theplanet. For Hutton, the Earth should be considered as a physiological system and the

heat inside the planet, its engine, moving material around and keeping it alive. Hisperceptions in the late 18th Century are similar to the Gaia principles today; the Earthas a whole interconnected system. Huttons discoveries were extraordinary for thetime; the popular explanation being that rocks were solely formed throughsedimentary processes where layers are built up over time. His ideas, which laterbecame know as Plutonism, focused on the notion that the heat in the Earth madesome rocks molten, which lead to changes in their structure. One example of this isGlen Tilt in Perthshire which Hutton visited in 1785. He noted the existence ofboulders made from metamorphic schist that showed intrusions of pink granite,implying that the granite had been molten and then cooled.

Within Huttons theory of Plutonism is the concept of a very long geological timescale

with no vestige of a beginning, no prospect of an end. At the time of his writing, thestandard theological dogma was that the Earth was very young, about 7,000 yearsold. Hutton considered it to be pointless to discuss the age of the planet because, asa natural system that is constantly changing, there is no beginning and end, just asuccession of different worlds. Hutton regarded Siccar Point in Berwickshire asconclusive proof of his geological theories; today it is perhaps the most famousgeological location on the planet. Professor Stewart described how at Siccar Pointthere are two obvious types of rocks; horizontal Old Red Sandstone overlies theolder, grey, vertically-upstanding rocks (Silurian greywacke). The older grey rocksare formed from mud laid down on the ocean bed; marine organisms in them showthat it is from the deep ocean over 1000 metres deep. The Old red sandstone rocksare completely different and are derived from sand and gravel laid down in a desert

environment. Between the two rock forms there is an irregular erosion surface.Hutton studied this environment and understood that it would take millions of yearsfor this landscape to form; firstly for the sediments to form, then for these to raise upto the surface, plus the time needed to erode that landscape and then for the next

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desert landscape to form on top of this. Thus, the basic template of the theory of theplanet was devised by Hutton in the late 18th Century and Scottish rocks underpin theunderstanding of modern geology.

A new global theory of the Earth developed in 1960s, including an understanding ofplate tectonics developed by Arthur Holmes at Edinburgh University. He firstpresented his theories in the 1920s, but his ideas were not widely accepted until the1960s. Today, his model is the one used in the modern understanding of platetectonics; the planet exudes heat, causing the surfaces to crack, which creates mid-ocean ridges and spreads a conveyor belt of rock across the ocean floor. This newrock cools, becomes more dense and, as it gets older, is so cold and dense that itbecomes unstable and sinks back down into the mantle resembling an elegantplanetary recycling system. This system is not just recycling rock, but also gases andwater. It is this process that continues to provide us with water and is responsible forour atmosphere. Today, these concepts are known as earth system science.

Professor Stewart commented that when people think of a country, they often have a

very clear idea of what defines that country; people pick certain moments from acontinuum of history that define the nation. In geological terms, it is difficult to definethe age of a country the rocks under our feet are all part of history and have had anextraordinary journey through a whole series of past Scotlands. Indeed, in reality,Scotland is made up of fragments of other places and has a complex history.Professor Stewart admitted that, at first glance, rocks can be very boring; they aremostly grey! He cited the example of rocks found in a stone wall in Rhynie inAberdeenshire which are around 407 million years old. At the time they were formed,the world looked very different; places we now know as America, Mexico, etc. wereall located in different parts of the globe and Scotland and England were nowherenear each other. The rocks at Rhynie are important because, if they are cut andpolished, exquisite fossil evidence of stems of plants, including some at cellular level,

are clearly evident in the layers of volcanic sinter. These rocks are the earliestevidence of ecosystems and, as such, Rhynie is a site of international importance.Such rocks, therefore, are not just rocks, but portals to the past.

In the mid 1800s, the geologist Roderick Murchison was the Director of theGeological Survey and subscribed to the traditional theory that rocks formed insedimentary layers with the oldest at the bottom and the youngest on top. Someamateur geologists, including a school teacher, Charles Lapworth, suggested thatthis wasnt always the case and quoted the example of Knockan Crag in Assynt,where it appeared that the rocks at the bottom were the younger specimens.Discussions on the subject continued for decades, as Murchison had no time forthese suggestions. However, when he died the Geological Survey was taken over by

Archibald Geikie. Geikie decided to put an end to these claims and arranged for ateam of experts to visit the area and map the geology with the intention of reinstatingthe Surveys reputation as the expert geologists. Two experts, Ben Peach and J ohnHorne, visited the outcrop and did indeed discover that, as the amateurs hadsuggested, the older rock was on top; a lack of fossils in rock indicates an older age.However, they also noticed a narrow band of crushed rock lying between the otherlayers of rocks; described as a vast rolling and crushing mill of irresistible power.

Their discoveries led to the assessment that the order of the layers of rock was beingdisturbed by a slab of rock being pushed up and over another one through tectonicaction; the old rock from lower down was being pushed up and put on top of youngerrock. Until this time, theories relating to building mountains focused on the notionthat they were pushed up from the base; this notion of a sideways thrust creatingmountains was therefore a revolutionary thought in geology. Peach, Horne and theirteam continued to map the area for ten years, in incredible detail. Henry CadellFRSE also studied the geology of this area and developed a geological experiment

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which attempted to recreate the Earths processes. He showed that forces coming infrom the side can push rocks on top of each other and form mountains resembling alayer cake of slices of different aged rocks on top of each other. The structure thatthese geologists discovered in early 20th-Century Scotland, through their detailedmapping, is now known as the Moine Thrust.

Scotland is one of the best places in the world to study geological formations;geologists have been studying and recording here for centuries. There are manyvarieties of rocks and the country has been exposed to periods of glaciation in thepast. Carbon dioxide (CO2) levels from 400 to 500 million years ago can beascertained from the chemistry of plants left in vegetation traces. Plants firstdeveloped about 450 million years ago in an extremely warm time period, when therewas a lot of CO2 in the atmosphere. Plants photosynthesising immediately started todraw down the CO2 and, at the same time, oxygen was being pumped into theatmosphere; CO2 levels went into freefall over the next 50 to 100 million years.Normally, when vegetation dies it decays and the CO2 is released back to theatmosphere; however, this was not happening and the CO2 was remaining trapped in

the root systems, leaves and stems. As such, the atmosphere was becoming lessCO2-rich and consequently the air temperature was dropping. Evidence of theCarboniferous period, about 300 million years ago, can be seen in the fossilised treetrunks found on the Fife coast, with carbon still locked in. The changes in atmospheretowards the end of the Carboniferous period led into the Ice Age, with ice sheetsnearly reaching tropical areas. In the Carboniferous period, the oxygen-richatmosphere meant that giant beasts, including dragonflies up to 1.5 metres wide,were common and, although the Carboniferous period was short-lived, importantly,Scotlands coal deposits were formed in this period from the preserved vegetation.

The extraction of fossil fuels for human use started in Scotland in the mid 19thCentury, when J ames Paraffin Young patented a new extraction process for the oilfound in the shale rocks to the west of Edinburgh. For a short time, Scotland was the

centre of a global oil industry, before the expansion of the industry in the Middle Eastmeant that Scotland could not longer sustain it in economic terms.

Professor Stewart continued by considering how Scotlands rocks are protected andtreasured today. The first geological map of Scotland shows the diversity of the rocksin the country and Scottish stone has been exported across world throughout thedecades; indeed, much of New York was built from Scottish stone. Stone builtScotland; the evidence can be seen in our cities streets and stone, as an industry,worked for a living. However, today, many quarries are going out of business, butstone remains important as part of Scotlands heritage. The Geological ConservationReview (GCR) aims to highlight sites of importance to the international community.

These are sites that are scientifically important because they contain exceptional

features that are not found elsewhere, or they are sites that are nationally importantbecause they are representative of our history our Crown Jewels. ProfessorStewart stated that it would be possible to reconstruct the entire history of Scotlandsancient past from the GCR sites. There are 834 GCR sites in Scotland, includingSiccar Point and Rhynie, 77% of which are afforded Site of Special Scientific Interest(SSSI) protection, which deters their destruction or impairment from activities such asbuilding works or fossil seekers. However, 23% of Scotlands GCRs are notprotected, including some of the most unusual and important sites. For example: AnCorran on Skye, which has some of the earliest dinosaur footprints in the UK; LochMorar, where contorted rock strata can be seen; and Tyndrum, where there is earlyevidence of mining. Reasons for a lack of protection include the associated financialcosts; more finance has been put towards protecting biodiversity instead.Furthermore some authorities are less willing to award protected status in case ithinders industrial and economic development nearby. Professor Stewart asked whatdo we want to do with our rocks? The answer isnt to just protect them and keep

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them away from people; they have a role to play and should be important ineducation. Scotland needs to promote geology, understand it and appreciate it, androcks need to be allowed to communicate their heritage.

Global Geoparks are areas of outstanding geology, where the geology underpins thecommunity and is part of the sustainable future of that community. There arecurrently two Global Geoparks in Scotland in Shetland and the NorthwestHighlands. The process for inclusion is constantly being revised and updated and, inthe last round, Lochaber Geopark was considered not to have enough support tocontinue being a viable Geopark, according to UNESCOs criteria, and was demoteddue to its lack of sustainable investment and salaried staff. The Lochaber Geoparkstill carries out the same work and functions as a Global Geopark, but is not classedin the official status. The Northwest Highlands and Shetland are due for renewal inlate 2013 and indications are that they will face the same issues as Lochaber.Furthermore, later in 2013, UNESCO is likely to raise the status of Geoparks to thesame level as World Heritage Sites; as such there needs to be a change of attitudeto make Geoparks important in Scotland and ensure Scotland continues to have a

Geopark presence. Professor Stewart commented that almost any part of Scotlandcould be a Geopark, and countries the world over are queuing up to becomeGeoparks. However, there is not the same emphasis on their importance in Scotland.

He commented that there needs to be a sea-change in terms of attitude to ensure thecontinued importance of geology in Scotland. It is nearly thirty years since the lastgeology teacher graduated in Scotland. Moreover, the number of students studyinggeology at school continues to fall; in 2011, 60 students took Higher Grade Geologyand this fell to 17 in 2012. From 2013, Scottish Higher Geology has beendiscontinued. These low numbers reflect the fact that no geology teachers have beenproduced for nearly 30 years. In England, however, GCSE and A-Level studentnumbers are increasing.

On a positive note, Scotland is the first country in the world to develop a geodiversitycharter. The Scottish Geodiversity Charter has been signed up to by keyorganisations such as Scottish Natural Heritage, the British Geological Survey, theRoyal Scottish Geographical Society and several local authorities. Professor Stewartemphasised that this is a tremendously encouraging step, but one that now needs tobe followed up by resolute action to protect and enhance Scotland's remarkable geo-heritage. Furthermore, Scotland needs more new initiatives to get people interestedin the subject. Geology is important not only to Scotlands cultural and economichistory and heritage, but also to its future, as it underpins many vital industries,including tourism, oil and gas. It is also integral to the development of new energysources; for example, carbon storage and fracking.

A Vote of Thanks was offered by Professor Graham Caie FRSE.

Opinions expressed here do not necessarily represent the views of the RSE, nor of its FellowsThe Royal Society of Edinburgh, Scotlands National Academy, is Scottish Charity No. SC000470