The Edinburgh Geologist
Magazine of the Edinburgh Geological Society Issue No 59 Spring 2016 The Edinburgh Geologist Issue 59 Spring 2016
Cover Illustration An aluminous eclogite from Verpeneset, Nordfjord (Central Norway), composed of omphacite (bright green), garnet, clinozoisite, quartz and kyanite. Parts are altered to phengite, talc and tremolitic amphibole. The amphibole-bearing cores of the garnet have been dated at c. 425 Ma and their eclogite–facies rims at c. 405 Ma. The mineralogy shows that the rocks reached pressures of 28.7 kilobars and temperatures of about 700°C. For more on eclogites see the excursion article by Beverly Bergman and others. Photograph by John Mendum.
BGS images are reproduced by permission of the British Geological Survey ©NERC. Published March 2016 by The Edinburgh Geological Society (Charity registered in Scotland number SC008011) www.edinburghgeolsoc.org
Editors Phil Stone Bob McIntosh [email protected] [email protected] British Geological Survey The Lyell Centre Research Avenue South Edinburgh EH14 4AP ISSN 0265-7244 editorial
Here’s tae us; wha’s like us?
An editorial ramble by Phil Stone
This issue of The Edinburgh Geologist different ways, on the EGS. Our has evolved into a celebration of the book review for this issue is the activities of the Edinburgh Geological second edition of Brian Upton’s Society, touching on the Society’s Volcanoes and the Making of history, excursions, publications, lecture Scotland, whilst A Geological programme, awards and financial Excursion Guide to the Stirling support for geological fieldwork. We and Perth area is the latest in can be justly proud of the achievements the Society’s series of regional made in all these areas, as illustrated by handbooks intended to encourage the selection of articles herein. the exploration and enjoyment of Scotland’s geology. Brian is a long- First, something of the Society’s standing member of the Society history is celebrated by Hamish perhaps best know for leading Johnston, who describes the many field excursions and as the involvement of the eminent 2000/2001 Clough Medallist; mineralogist Matthew Heddle (his his contributions were recently great-great-grandfather) soon after recognised by promotion to a the founding of the Society in 1834; Society Distinguished Fellowship. Heddle became President in 1851. Another EGS member elevated to a Back in January this year, Hamish Distinguished Fellowship at the same lectured to the Society on Heddle’s time, Mike Browne, was responsible, life and achievements, and his in collaboration with Con Gillen, recently published biography of the for pulling together the Stirling and great mineralogist can be thoroughly Perth guide. It has been a long- recommended. As an aside, but term project for the two of them remaining on a presidential theme, and it is good to see the finished this seems like a good opportunity to product turning out so well. The welcome back Stuart Monro for his book is well laid-out and illustrated second stint as EGS President. in colour, with an eclectic mix of eighteen excursions drawn-up by And thinking of books, there are two combinations of sixteen contributors. deserving of mention that reflect, in The geology of the area affords
1 editorial much geological variety: Dalradian, Earthwise, devised and hosted by Highland Border Complex, Devonian the British Geological Survey. The and Carboniferous sedimentary EGS content supports an anthology and igneous rocks, and Quaternary of Scottish geological walks, and deposits and landforms. All this is the format allows easy additions supplemented by features on the of access or locality information, building stones of Perth and Stirling, with the tempting facility to upload and on the mineralisation at Alva. notes, comments and photographs immediately after — or even during — a field excursion. What will they think of next?
Staying with the excursions theme, we have an interesting, multi-author account of the geology experienced by participants in last summer’s Society excursion to the Norwegian Caledonides; thanks to Beverly Bergman for pulling it all together. Eclogites clearly featured prominently (hence our cover picture) but were not the only fascinating and attractive rocks to be seen, with the back story of high-grade metamorphism and polyphase structure adding bewildering complexity. It’s obvious from the ‘daily diaries’, each written- up by a different contributor, that the excursion leader, Simon Cuthbert, proved remarkably adept at The Stirling and Perth excursion explaining it all — even in the rain! guide represents the traditional face of EGS publications, but these days A very different geological an online approach is also necessary. experience is described by two M. In his article, Bob McIntosh explains Earth Sc. students at the University how the Society’s publications of Edinburgh. Rachel Whitty and are being incorporated into an Isla Simmons travelled to Iceland interactive, web-based platform, during the summer of 2015 as
2 editorial volunteer assistants in the island’s Geological Survey is abandoning volcano monitoring programme, Murchison House, its Edinburgh an enterprise for which the EGS home since 1976, and moving out provided some financial support to the new Lyell Centre at Heriot- through its Clough Fund. Some of us Watt University’s Riccarton campus. enjoyed a summary of their volcanic The EGS has enjoyed a supportive, experiences at Fellows’ Night and fraternal relationship with the Survey their contribution to this issue of EG is for many years but, inevitably, with most welcome — it’s also informative the move our links will be strained and entertaining and demonstrates or perhaps even severed, at least good use of ‘Clough’ resources. Just in the short term. Maintaining or to remind everyone (and to alert any rebuilding those links will be one of potential future applicants), grants the challenges facing Stuart Monro from the Clough Fund are normally as he resumes presidential office. of the order of a few hundred It’s encouraging to note that his pounds and are available to support two newly-elected vice-presidents, geological work at home or abroad. Bob Gatliff and Emrys Phillips, both Grants may be awarded for fieldwork occupy senior positions within BGS or other geological enterprise in any and so are ideally placed to restore area, provided that a suitable Scottish the proper state of affairs. Good luck connection can be demonstrated gentlemen. through the recipient or their institution, or through the work itself.
Goodbye Murchison, hello Lyell
You might have noticed that inside our front cover the editors have a change of address. As EG goes to press, the British
The Lyell Centre nearing completion early in January 2016.
3 john horne’s memoir John Horne’s Memoir — Signatures from the 1912 & 1914 Assynt excursions
By John Mendum
During recent stocktaking at The flyleaf also contains the signatures Murchison House a copy of the relating to an excursion undertaken Northwest Highlands Memoir in 1914, when John Horne took a (Peach et al, 1907) was found in the further party to Assynt. Attendees Palaeontological Department. It has included Sir Alexander and Lady been rebound but is in excellent (Rachel Workman) MacRobert, condition with little signs of use and but also included the well-known no obvious foxing. The memoir geologists Reginald A Daly and contains detailed descriptions of Professor Molengraaf. Rachel the Lewisian, Torridonian, Moine Workman, the daughter of the noted and Cambrian-Ordovician rocks American mountaineers William in the Durness to Kyle of Lochalsh and Fanny Workman, was educated area, summarising the results of the at Cheltenham Ladies College and survey’s detailed work there in the gained a degree in geology from the late 19th century. This copy patently University of London in 1902. She belonged to John Horne who was undertook research and published Assistant Director in the Geological papers on alkaline igneous rocks (e.g. Survey in Scotland from 1901 until carbonatite and nepheline syenite) his retirement in 1911. and was one of the first women to be elected a fellow of the Geological The flyleaf of the memoir contains Society in 1919. Information on the signatures of 29 attendees of the MacRobert Trust, including her the renowned 1912 excursion to ladyship’s contribution to the Second Assynt, which followed on from World War effort, can be found at a British Association meeting in http://www.themacroberttrust.org.uk/. Dundee in mid-September that year. The memoir is to be archived by BGS. This excursion, led by Peach and Horne, was attended by 31 notable Peach, B N., Horne, J, Gunn, W., European and British geologists (see Clough, C T, Hinxman, L W and Teall, Barber, 2010). J J H. 1907. The geological structure
4 john horne’s memoir of the northwest Highlands of Scotland. Memoirs of the Geological Survey, U.K.
Barber, A J. 2010. Peach and Horne: the British Association excursion to Assynt September 1912. In Law, R D, Butler, R W H, Holdsworth, R E, Krabbendam, M and Strachan, R A. (editors) Continental Tectonics and Mountain Building: The Legacy of Peach and Horne. Geological Society, London, Special Publications, 335, 29–49.
The 1914 excursion group. Lady MacRobert is seated third from right, middle row, next to John Horne. BGS image P883132.
5 matthew forster heddle and the edinburgh geological society Matthew Forster Heddle and the Edinburgh Geological Society
By Hamish H Johnston
Matthew Forster Heddle (1828– 1897), author of the classic work The Mineralogy of Scotland (1901), is a name familiar to members of the Edinburgh Geological Society (EGS). In 2002 I was able to help Peter Dryburgh, whose paper on the story behind his copy of Heddle’s great work was published in Edinburgh Geologist number 39. The book originally belonged to Heddle’s daughter Cecilia, who was my great- grandmother. Since then, retirement has given me the time to research and write the first-ever biography of Heddle. Matthew Forster Heddle: Mineralogist and Mountaineer combines original research and family records to provide much new material and the fullest available account of Heddle’s life and work. It includes the full story of Heddle’s The biography is published by NMS involvement with the EGS, of which Enterprise Ltd., ISBN 978 1 905267 he was President from 1851 to 1853. 98 9. 270 pp. Price £14.99. 2015.
The book also gives a full account scientific work, his role in founding of Heddle’s childhood, education the Mineralogical Society, his and medical career, his time (and prolific papers in theMineralogical troubles) at St Andrews University, Magazine and for the Royal Society his comprehensive exploration of of Edinburgh (which led to the Scotland’s mainland and islands, his award of its prestigious Keith Prize),
6 matthew forster heddle and the edinburgh geological society his mountaineering achievements, Heddle spent several months in his role in the controversy over the the German mining and teaching geology of North-West Scotland, centres of Clausthal and Freiberg, his involvement in the goldfields of where he studied and returned South Africa, the destination of his with valuable mineral specimens. great mineral collection, and the He catalogued his collection of writing of his encyclopaedic The some 560 items in a notebook Mineralogy of Scotland (1901). entitled Cabinet of Minerals 1850. On his return Heddle completed Heddle’s parents came from Orkney. his M.D. thesis, The Ores of the With a large fortune made from Metals. Heddle graduated in 1851 trading in West Africa his father and for the next five years worked, bought the Melsetter estate on Hoy somewhat reluctantly, as a doctor in in 1818, and married the daughter the Grassmarket area of Edinburgh. of its bankrupt owner. Heddle and His home was in Clarence Street in his siblings were orphaned in 1842, Stockbridge. A contemporary wrote by which time he was at school in later that while at University Heddle Edinburgh, first at the Academy and had given almost exclusive attention then at Merchiston Castle, to which to mineralogy. Another remarked on he was moved by his Curators. In the size and quality of his collection, 1844 Heddle began medical studies and the laboratory he set up in his at the University where he was taught home. Mineralogy, not medicine, was by such eminent professors as James Heddle’s true interest. Young Simpson (1811–1870). The medical curriculum included Natural This was the young medical student History, of which the Professor who, enthused by his German travels, was the great Robert Jameson joined the EGS in late 1850. Earlier (1774–1854). With William Gregory Heddle had met the collector and (1803–1858), Professor of Chemistry, teacher Alexander Rose (1781–1860) Jameson was to be a major influence whose classroom in Drummond on Heddle, who had already Street was used for EGS meetings. developed a collecting habit — first It was here that Heddle first met plants, and then rocks and minerals. Archibald Geikie. Rose had been The first documented record of a co-founder of the EGS in 1834, Heddle’s mineralogy is in 1846 but by now the Society was rather when he gave a collection to a newly moribund, with no minutes kept established museum in Kirkwall. for the two years from December In 1850, encouraged by Jameson, 1849. In October 1850, the Vice-
7 matthew forster heddle and the edinburgh geological society
President, James Brown, submitted a lengthy report on the poor state of the Society. While the Society had low fees, a meeting room and museum, its membership was only 27, including the 5 office bearers. Attendance at meetings was poor. Sometimes speakers did not turn up. There were no organised excursions. Importantly, the Society did not publish Transactions, and academics and gentlemen did not deign to join. Brown told the Society that it must change, and aspire to compete with other recognised scientific Societies.
The first published reference to Heddle and EGS is a report in The Scotsman of a meeting in February 1851 at which Heddle spoke on the Alexander Rose (1781–1860) in later chemistry of imported guano, and life. BGS image P228693. on the mineral prehenite found in Scotland. Heddle was soon noticed for his ability and for instructing President unanimously at the next other Society members, so when at meeting on 18th December 1851. the meeting on 4th December 1851 the time came for annual elections, Heddle was to be President till 1853, Alexander Rose, probably responding then Vice-President till October to Brown’s criticisms, nominated 1862. During the two years of his Heddle for the post of President. presidency Heddle gave 8 talks and Despite this the 5 members present demonstrated specimens on such (Heddle not being among them) topics as titanium, emerald nickel, elected Rose but he declined the post. edingtonite, and the analysis of The meeting closed with no decision zeolitic minerals. A talk on metals in reached. Rose must then have the native state was so complex that leaned on those opposed to Heddle he was asked to reprise it in sections (who was only 23, and straight out of on later occasions. During Heddle’s University) because he was elected presidency the Society also discussed
8 matthew forster heddle and the edinburgh geological society
is now the National Museum of Scotland came into being in the 1860s. In 1854 the Society urged the speeding up of the mapping of Scotland by the Trigonometrical Survey, and in the same year it even lobbied for the introduction of decimal currency!
If Heddle presented innovative papers to the EGS his role as President was less impressive. The Society met on 38 occasions during Heddle’s presidency, but he was present at only 17 meetings. A year after he stepped down to Vice-President his attendance and input dropped off to almost nothing. It is clear from Edinburgh Geological Society’s the perfunctory minutes that as minute book recording Heddle’s President Heddle made no progress election as president. By permission on Brown’s recommendations, and of Edinburgh University Library that under him the performance Centre for Research Collections. of the Society was little better than before. While Heddle was an expert and enthusiastic mineralogist, he other matters. In 1852, and again in was not a committee man. Also, the 1853, it lobbied government for the EGS needed a reforming leader, and replacement of Jameson’s College while Heddle may well have had Museum (which was already too some good ideas, the aged Rose, to small) with a new Natural History whom the Society owed much, was Museum in Edinburgh. Heddle’s the Secretary, hardly the man to drive motion that it should be free to the change. public at all times was seconded by Rose, and the Society agreed to One obvious reason for Heddle’s hand over its collection of minerals. absences is that he was a working Heddle was charged with preparing doctor, but there was another reason. the case. In due course, with other Heddle had learned from Jameson bodies also urging action, what the importance of publishing
9 matthew forster heddle and the edinburgh geological society scientific papers, and he was very keen to share his own discoveries. The EGS did not publish Transactions, so Heddle had to look elsewhere. Before he became EGS President in 1851 Heddle had already become a Fellow of the Royal Physical Society of Edinburgh (RPSE — not the same organisation as the Royal Society of Edinburgh). Between December 1854 and April 1856 Heddle read and published 8 papers with the RPSE and in 1856 he was elected a Council member. Also, between 1855 and 1859, 13 Heddle papers were published in David Brewster’s Philosophical Magazine, then the country’s most prestigious scientific journal. Here Heddle was in Matthew Forster Heddle (1828– illustrious company: in March 1855 1897) in his favourite environment. Heddle’s Analysis of the Mineral By permission of National Museums ‘Edingtonite’ was bracketed by papers Scotland. from Boole and Bunsen.
All in all, It is not surprising that the Heddle’s departure. It found new EGS, and indeed medicine, were accommodation, greatly improved not top of Heddle’s priority list. He its administration, engaged in some was appointed temporary Assistant clever public relations, improved Professor of Chemistry at St Andrews its membership, and from 1867/8 University in 1856 to cover for the began to publish Transactions. It also sick Professor Connell, but it was started to attract eminent honorary not until 1862, when he became members, although Heddle was not Professor in his own right, that he among those invited. In 1884 he left the EGS. He then appears to was elected to associate (honorary) have had little more to do with the membership, however, and in March Society until much later in his life. 1897 Heddle read his On Analcime The EGS took off in the mid-1860s, with New Forms at the EGS, a few not long after Rose’s death and months before his death.
10 the egs long excursion to norway 5–12 june 2015 The EGS Long Excursion to Norway 5–12 June 2015
By Beverly P Bergman, Christine L Thompson, Richard A Smith, David Blythe, Stephen Livera, Alison Tymon and Douglas Holliday
The steadily-growing pile of our destination, Selje (Figure 1), we suitcases, rucksacks, sticks and quickly settled into our hotel and self- boots at a convenient rendezvous catering accommodation and met by the atmospheric (in more ways up with our leader, Simon Cuthbert than one) Fisketorget (Fish Market) (University of the West of Scotland in a sunny Bergen, Norway, bore and Geological Society of Glasgow). witness to the imminent arrival of Selje (185 Km north of Bergen) an intrepid party of geologists, at the is most conveniently situated for start of the Edinburgh Geological exploring the eastern (Scandinavian) Society’s first venture into foreign half of the Caledonian collisional belt, parts. As the afternoon drew on, we the orogen’s western counterpart embarked on the high-speed (well, being on the east coast of Greenland. relatively speaking) ferry which was to take us northwards through a During our six days at Selje, we magical landscape of narrow fjords, began with the orogen’s deepest mountains, and even, for the sharp- exposed levels and worked our way eyed, a glimpse of a spectacular up through a pile of thrust sheets example of retrocharriage on one of the islands in the distance. Eventually we crossed the broad (c. 4.5 km) Sognefjord and reached the area which was to be our home for the next week. Arriving at
Figure 1 View from above the hotel at Selje © Alison Kerr
11 the egs long excursion to norway 5–12 june 2015
(‘allochthons’) to the youngest the rest of our week in Norway, we rocks (Devonian) in the area. On built up a plate tectonic explanation for the first day Simon introduced us the co-existence of the crustal gneisses to the Western Gneiss Complex; with mantle-derived eclogites and for Proterozoic basement rocks revealed their relationship with the overlying through a ‘window’ in the overlying thrust sheets. thrust-sheet pile. A walk along the shoreline immediately north The following day brought a veritable of the hotel introduced us to the feast of spectacular eclogites, and gneisses, typically pink and grey apart developed the theme of the previous from pods of mafic metamorphic day that some eclogites had been in rock enclosed within them. We the mantle alongside their country halted at Grytting, where two of rocks. This concept was reinforced these pods are clearly of eclogite. with further evidence of ultra-high- They are now a national scientific pressure metamorphism in both the monument because it was here in eclogites and the surrounding schists 1921 that the Finnish petrologist, and gneisses. The day culminated Pentii Eskola (1883–1964), realised with a visit to Verpeneset to examine that eclogite, being of high density, two large eclogite bodies including must have formed under ultra-high a stunning bright green omphacite load pressures and therefore at great + garnet + kyanite + clinozoisite + depths. He designated one of the two quartz eclogite. [see cover picture–Ed] pods as the type locality of ‘eclogite- pegmatite of the Grytting type’. Day 3 introduced rocks that had escaped such extreme In 1984 the other pod was found to metamorphism and demonstrated contain the very high-density form of characteristics of the old Proterozoic silica, coesite, an indicator of ultra-high- crust of Baltica. The first stop was at pressure metamorphism, such as would Flatraket, a large roadstone quarry be experienced at mantle depths of which included both deformed 70 km or more. How did such high- and undeformed granulite facies pressure rocks come to be enclosed coarse-grained monzonite, known in apparently lower-grade gneisses? locally as ‘mangerite’ (Figure 2). Simon explained that more recent In places this spectacular rock discoveries of microscopic evidence contains characteristic large cm- of coesite and even diamond in the diameter undeformed spherical gneisses suggested that they too had orthoclase feldspars with locally experienced mantle conditions. Over well developed white plagioclase
12 the egs long excursion to norway 5–12 june 2015 reaction rims. Original zircon ages of about 1520 Ma are recorded from the intrusion and the granulite facies shows low P-T conditions compared to other rocks seen earlier and surrounding the monzonite body. The quarry also contains dark meta- gabbros containing pink garnets, the first stage of a gabbro to eclogite transition. The meta-gabbros are thought to be basic dykes intruded into the monzonite and their margins were sheared. Further well developed green epidote-lined shear zones are recorded throughout the mangerite.
Moving on to Krakenes, the sun shone and there was a beautiful view of the lighthouse and fjord coastline (Figure 3). This headland Figure 2 Aspects of the variable includes another rapakivi-textured deformation in ‘mangerite’ at monzonite (Figure 4) with well- Flatracket Quarry. Photographs exposed, dark mafic enclaves where © Beverly Bergman. feldspar had recrystallised in the original basaltic rock. Again, the monzonite is adjacent to dark layered reaction catalyst and in its absence, gabbro which shows only partial reactions are so sluggish that it is evolution to eclogite. These bodies possible to get unreacted plagioclase are surrounded by migmatitic and at 10 kbar. The day finished with a non-migmatitic paragneiss which visit to the Kannesteinen coastal rock contains coesite. It is not clear why pedestal on Vågsoy Island, which was the mangerites demonstrate relatively enthusiastically photographed before unmodified conditions, where the attention was diverted back to the plagioclase feldspars have not reacted beautifully deformed eclogite pods in to form pyroxene and garnet, and the adjacent wave cut platform. it is thought that the rocks may have been too dry to re-crystallise. Early on Tuesday 9th June we visited Eclogite minerals need water as a the Lien Nature Reserve which
13 the egs long excursion to norway 5–12 june 2015
Figure 3 Coastal section at Krakenes. © Alison Kerr.
Gneiss Complex (a subducted part of Baltica) from an over-thrust slab of Laurentia. The reserve was created to protect garnet covers part of the Almklovdalen peridotite masses within the chlorite peridotite body, near Åheim. The peridotite and dunite that form peridotite body is considered to be most of the body. The mantle block a block of sub-Laurentian mantle, is about 4 km across at outcrop, which dropped into the Western but the garnet peridotite pods within it are only about 150 m in length. Previous specimen collectors had ravaged the pods so the area has been protected by law against further hammering and collecting. The surrounding hills of the ultramafic massif are distinctly Figure 3. brown-coloured and the vegetation sparse, so we were delighted to get to the top of the hill and find the variegated colours in the excellent garnet peridotite exposures skirted by sparkling purplish-red garnet fragments. The rocks all contain Figure 4 Rapakivi texture in olivine with an extremely high monzonite (monzogranite s.s.), magnesian content indicating that Krakenes. The largest megacryst is these mantle rocks were depleted about 2 cm in diameter. Photograph after a mafic magma had been © Beverly Bergman. extracted from them.
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The garnet peridotite contains a spinel with some pyroxene in places metamorphic assemblage of olivine (Figure 5). This is the result of a + orthopyroxene + clinopyroxene + decompression reaction between garnet, which is regarded as having olivine and garnet which occurred been formed during mid-Proterozoic during the later Caledonian history. times, while the peridotite was still in the mantle. The garnet peridotite Our next stop was Gusdal Quarry and garnet pyroxenite interlayering is where a major constituent of the considered to reflect dyke intrusion Almklovdalen peridotite body, dunite, in the mantle. Because of the is quarried. The fresh, anhydrous layering, folds can be seen which olivine is crushed to 3 mm grain predate the pervasive amphibole and size and fed through a tunnel to a chlorite fabric in the main peridotite deep-water loading facility at Åheim. body. Within the garnetiferous pod, Most of the olivine is used as a slag purplish-red chrome-rich garnets conditioner in the iron and steel are typically surrounded by green industry and is exported to countries ‘kelyphytic rims’ composed of small such as the UK, Brazil and India. With radiating grains of amphibole and an annual production of 1.8 million
Figure 5 Garnet peridotite, Lien Nature Reserve. Chrome-rich garnets showing green ‘kelyphytic rims’; the largest garnet is about 2 cm long. Photograph © Richard Smith.
15 the egs long excursion to norway 5–12 june 2015 tonnes, the quarry has an estimated strung-out lenses of pink and green life-span of 100 years but could be minerals, with some shear indicators. extended to recover much greater Above the NSDZ is a series of volumes, possibly for up to 300 years. nappes which piled up on Baltica as the Iapetus Ocean closed. The Finally, beside the road to Lower Allochthon gneisses were Raudkleivane olivine quarry, now invisible in the mist, but we observed, closed, we examined exposures of from the refuge of a convenient chlorite peridotite enclosing boudins bus-shelter, a hillside of very thick of ‘internal’ eclogites. The chemistry Middle Allochthon quartzites, once of the eclogites suggests they a psammitic continental cover, now originated as dykes intruded into the tilted nearly vertically. At Kalvåg, we upper mantle during the opening of ate our packed lunches, hunched the Iapetus Ocean. Their mineralogy miserably in the minibuses in a indicates that subsequently, they and grim, dark and wet graphite schist their host peridotite, after dropping quarry with pale metacherts, the into the descending Baltic slab, were altered ocean sediments above carried further down before being an obducted ophiolite sequence exhumed. ‘External’ eclogite pods dated to at least 442 Ma. At the are also found in the surrounding Rylandsvatnet reservoir we braved gneissose country rocks. the rain and wandered over ice- rounded greywackes contained in The following day, the overcast huge olistoliths in a melange, and conditions of the previous few days thermally metamorphosed to spotted gave way to torrential rain, testing rocks containing lumpy masses of both Gore-Tex® and enthusiasm cordierite and sillimanite crystals by for geology. The programme for the granodiorite sheets emanating from a day took us away from the Western nearby intrusion. But the day ended Gneiss Complex into the nappes/ splendidly with a stop at Bremanger, allochthons above the Nordfjord- where the whole group piled into an Sogn Detachment Zone (NSDZ). extravagantly decorated cafe run by We took the ferry across Nordfjord an exuberant Thai lady who fed us to look at 4 km thick ultra-mylonites with tea, coffee and paper bags full of which represent up to 100 km of prawn crackers. movement of the subducted crust of Baltica. Unsurprisingly, the dark The rain continued overnight, green, highly foliated rocks had contributing to the magnificence of
16 the egs long excursion to norway 5–12 june 2015 numerous waterfalls which we could deposition of the Hornelen sediments admire in addition to the geology. whose provenance is largely from The last day was devoted to an the Middle Allochthon and, more overview of the Middle Devonian locally on the northern margin, Hornelen Basin, which was not, as from the Upper Allochthon. Perhaps many of us had suspected, added to the most characteristic feature of the programme simply to appease the basin is the spectacular step- the soft-rock enthusiasts in the party, topography formed by abundant, but in fact formed the final preserved 17 volcano monitoring in iceland Volcano Monitoring in Iceland By Rachel Whitty and Isla Simmons Iceland is of such geological interest processed to compare the emissions of that, to anyone studying for a degree different gas compositions. Processing in Earth Sciences in Edinburgh, the the MultiGAS data was achieved using volcanic island just 750 miles to Ratio Calc 2.5, a software system the north is a huge draw. During allowing comparison of different gas the summer of 2015, and following emissions to find correlations. The our 4th year of university, we were Hekla MultiGAS station had a year’s excited to finally get there, with some worth of data backlog and our first help from the Edinburgh Geological job was to process this data. With two Society’s Clough Fund. of us working on the task, it took just over two weeks to clear the backlog, We had arranged for a month’s and collate the data from July 2014 voluntary work with Veðurstofa Íslands through to July 2015 into a format that (the Icelandic Meteorological Office) could be used for scientific research. which, together with the University of Iceland, is responsible for monitoring When we had finished processing Iceland’s many active volcanoes. The the data from Hekla, there was methods used include studies of gas then plenty of other unprocessed emissions and seismicity, with results data for us to work on, from the analysed to determine whether or not numerous other volcanoes around a volcano shows signs of unrest. We the country. It felt good to know that were taken under the wing of Melissa our work had real scientific value – Pfeffer (a gas volcanologist) and our this wasn’t just a course assignment main task was to process gas emission for university, this was real data data from Hekla, one of Iceland’s and processing it was of scientific most active volcanoes. importance. This was highlighted one afternoon when we were called Gas Processing in to a meeting with three visiting Gas emissions from Hekla are scientists from Italy who wanted to continuously measured by an discuss our results. Fortunately for us automatic MultiGAS station located the scientific language was English, at the summit. This data is sent to although conversations often slipped the office in Reykjavik, where it is into Icelandic or Italian. 18 volcano monitoring in iceland Seismic Monitoring tiny ferry terminal at Landeyjahöfn, As well as our daily work processing a 30 minute boat trip (complete with volcanic gas data, we also had the killer whale and puffin sightings) opportunity to be involved with other brought us to the island of Heimaey, scientific work being carried out at about 5 miles off the south coast of Veðurstofa Íslands. The seismology Iceland. At 13.4 km2, Heimaey is the department held a weekly meeting to largest and only populated island of discuss seismic activity in the country the Vestmannaeyjar, an archipelago over the past week, and we were of 17 volcanic islands and skerries. invited to attend. Most exciting for us was the day that an emergency The dramatic silhouette of Heimaey meeting was called — a seismic swarm appeared out of the drizzle as we had begun off the Reykjanes Peninsula sailed closer, towering cliffs rising overnight, and there was concern vertically from the sea to form a that this indicated a submarine rugged skyline with hundreds of sea volcanic eruption. We were just silent birds wheeling overhead. The volcanic observers, listening in at the back of cones of Eldfell and Helgafell could the room but it was fascinating to hear be seen dominating the island. Eldfell the discussions over the implications erupted without warning in 1973, of what the seismic activity may mean, destroying over 400 homes and and what should be done — was leading to temporary evacuation of the activity purely tectonic? Or was the island. As a fishing community, the an eruption imminent? Should the islanders depended on the harbour Volcanic Aviation Colour Code be for their livelihood and it was feared upgraded from green to yellow? that the advancing lava would block Should the coastguard be informed? it. With a lot of effort, the lava flows It was interesting to witness first hand were re-directed, saving the harbour. that science is not about right and wrong answers – it’s about evidence The purpose of our trip to Heimaey and interpretations, and things can get was to measure the gas emissions from quite heated when different people Eldfell. Melissa makes the trip every year have different views on a situation! to collect gas samples with the aim of building up a long term record allowing Fieldwork any trends to be observed. The red cone In our second week of working of Eldfell stands just behind the town at Veðurstofa Íslands we had the of Heimaey, composed of loose scoria, opportunity to help with fieldwork. with lava flows extending to the north After driving from Reykjavik to the and east. The climb to the summit took 19 volcano monitoring in iceland half an hour, scrambling up the path of loose scoria onto the horse-shoe shaped ridge where buttresses of solidified breccia stood out through the rubble. Numerous fumaroles covered the summit, emitting the gases that we were wanting to collect and sample. The high wind and low cloud meant that the only visible signs of the fumaroles were patches of yellow deposits where sulphur had precipitated. Our first task was to find a suitable fumarole to set up Field work on Heimaey: measuring the MultiGAS station — it needed to be the temperature of the fumaroles. releasing hot gas, and be sheltered from the wind. After installing the equipment, it was left to run and sample the gas while we retreated back to town for tea and cake, and to warm up. By the end of the afternoon the clouds had cleared and the wind had died-down, giving us the chance to collect gas samples when we returned to remove the MultiGAS station (samples can’t be collected in high winds). The second Field work on Heimaey: collecting time we reached the summit of Eldfell, gas in a Gigenbach flask. the sun was shining, with a beautiful view over the town and harbour. We found a sheltered fumarole with a visible thin plume of gas rising up Gigenbach flask. It was a slow process, from between the scoria. Using an but despite the chill in the evening air, electronic probe, we measured the it was wonderfully warm sitting on top temperature at over 250°C. Collecting of the fumaroles! the gas involved hammering a hollow metal tube into the scoria, attaching The following morning, after catching a syringe with which to suck up the the ferry back to the mainland, we gas, and then transferring it into a separated to join different fieldwork 20 volcano monitoring in iceland projects for the day. Rachel went with Melissa to the glacier of Solheimjökull to collect water samples from the glacier melt and take MultiGAS readings at the glacier snout. Meanwhile, Isla went with Baldur Bergsson (from Veðurstofa Íslands) to install equipment for measuring gas concentrations in the groundwater flowing from Hekla. Magma below Hekla releases gases into the groundwater, and it is hoped that changes in these gas concentrations, Hot springs at Hverigerði. especially SO2, will be able to be used as an early warning system for any future eruption. This is a the long and sometimes chilly days. joint project between the Icelandic We would like to say a huge Thank Meteorological Office and the British You to the Clough Fund for helping Geological Survey. make it happen. Travels in Iceland: Bibliography We spent our weekends exploring Mattsson & Höskuldsson, 2003. more of this fascinating country. Geology of the Heimaey volcanic We climbed the lava plateau of Mt centre, south Iceland: early evolution of Esja near Reykjavik, we camped in a central volcano in a propagating rift? the steaming geothermal town of Journal of Volcanology and Geothermal Hveragerði, and we explored the Research, 127, p. 55–71 rift valley at Þingvellir, the tectonic boundary between the European Thordarson & Larsen, 2007. and North American plates. The field Volcanism in Iceland in historical geology was great, but the whole times: Volcano types, eruption styles experience of working with real and eruptive history. Journal of data in an important and dynamic Geodynamics, 43, p. 118–152 scientific environment was the biggest benefit we gained from our month Rachel Whitty and Isla Simmons in Iceland. Helping monitor active MEarthSci students at the University volcanoes and making a genuine of Edinburgh scientific contribution was well worth 21 volcano monitoring in iceland The rift at Þingvellir: North American Plate and Rachel on the left, European Plate and Isla on the right. Pahoehoe lava at Þingvellir. Lava tunnel at Mývatn. 22 earthwise — evolution or revolution? Earthwise — evolution or revolution? By Bob McIntosh The British Geological Survey has still two dimensions but delivered produced maps and memoirs for over the Internet. BGS iGeology1 a large part of its history. The first has been available for some time, maps were published at a scale followed by iGeology 3D2, and of 1:63 360 in the 1830s; sheet more recently, Groundhog, the web memoirs or explanations were service that delivers the National an innovation by Sir Roderick Geological Model — a full 3D Murchison who introduced them representation of the geology of in 1857, the first beingThe geology the UK. All these products increase of the country around Cheltenham. our ability to visualise the geology, The maps evolved from the hand- making it more accessible for non- coloured Old Series to the colour experts (and experts!). However, printed New Series in about 1900. there is something missing from all Another major change came with this iGeology, 3D model activity. the introduction of metrication and We have seen that traditionally the the scale change to 1:50 000. This paper map and memoir were the brought in a fresh new design for basic Geological Survey products. new maps, of which the current The development of the map has paper maps are examples. A raced ahead and been transformed major innovation was the design into digital maps and 3D models, and production of maps by but the memoirs and other BGS computer, a process driven by the publications have stubbornly NERC Experimental Cartography remained as printed products. Unit — but the output was still a All this is about to change with paper map. ‘Earthwise’, a new web-based platform for delivering text3, and the To provide a clearer understanding Edinburgh Geological Society is part of geological maps for a wider of this text revolution! range of users, there has been a revolution over the past 15 years. 1 http://www.bgs.ac.uk/igeology/ The first step in this revolution was 2 http://www.bgs.ac.uk/igeology/3d.html to produce a purely digital map, 3 http://earthwise.bgs.ac.uk/index.php/Main_Page 23 earthwise — evolution or revolution? Anyone familiar with Wikipedia, 2. It is a collaborative authoring the massive online encyclopaedia, environment where BGS staff will immediately be at home with and users outside BGS can jointly Earthwise, as it uses the same create articles. underlying open-source software 3. Users can select articles of interest called Mediawiki. This provides and either download them or a ready-made application for the use the ‘Create a book’ facility to collaborative creation and editing have them custom printed as a of articles. Anyone with access to traditional paper publication. a computer and the internet can 4. Access is free through the BGS become involved in providing website. content for the whole world to 5. The free access will lead to a huge consult. From a BGS perspective, increase in use of the content for a decision was made that scientific a wide range of purposes and content would be delivered through provide much greater impact two routes. Traditional peer- for the science that is being reviewed journal articles would be published. complemented, in most cases, by 6. The Open Access scientific a PDF copy on NORA4, the NERC publishing method complements Open Research Archive. For the rest and invigorates traditional of BGS publishing, its memoirs, sheet publishing. descriptions, popular publications 7. It will greatly enhance and and open reports content would promote the earth sciences. be transformed into articles on 8. From the Earthwise platform a Earthwise, the Mediawiki platform. much tighter integration will be created between the digital maps Earthwise provides huge benefits and models and related descriptive over traditional print. text, fully replacing the traditional paper ‘map and memoir’ duo. 1. It is a fully interactive media- 9. For any earth science organisation rich environment where articles with limited IT expertise, can include more images and collaboration with Earthwise video and where content can offers a professionally hosted be hyperlinked to other sources, and run platform and an both in Earthwise and elsewhere opportunity to be part of a UK- on the internet. wide initiative. There could easily be some integration with that 4 https://nora.nerc.ac.uk/ organisation’s own website. 24 earthwise — evolution or revolution? 10. The text will be in a format that been converting content from its can be delivered through the guidebooks into individual Earthwise semantic web as linked data. In articles. Almost 90 excursions have the future, not just articles or web already been ‘extracted’ from pages will be linked to each other various EGS guidebooks and added but also data itself in an extension as individual articles on Earthwise. of the Web. This is all rather So far, for most, only the basic text technical and anyone interested has been added but the Society will should look it up on Wikipedia!5 create a small team of volunteers to check the current accuracy of This move from paper publication the excursions (many were written to a web-based platform is a over 20 years ago) and also enhance revolutionary change equal to that the content with additional field revitalising of the paper map as photographs and text. Unlike a 3D model. It opens up endless conventional publishing, content can opportunities in the way the text be added and updated immediately. can be delivered and used and in Earthwise will provide all sorts of 2016 we are right at the start of this opportunities to be creative, for exciting development. instance, notes about EGS excursions could quickly be put on Earthwise Earlier it was mentioned that the to be shared by all members and the Edinburgh Geological Society was public and then updated after the part of this text revolution. The EGS trip with photos taken on the trip by is one of the first organisations to participants. This would provide an work with the BGS in supplying up-to-date and ongoing, rich record text-based content for Earthwise. of all the Society trips and provide The central aim of the Society since a valuable resource for others who it was founded in 1834 has been would like to visit the same sites ‘stimulating public interest in geology independently. Another initiative to and the advancement of geological enhance the site which is in the early knowledge’. This has largely been stage of planning is to georeference achieved by organising regular all of the individual excursion stops, lectures and field excursions, and allowing them to be displayed on by publishing excursion guidebooks. web GIS. This may lead to an ‘app’ Embracing the new technology for mobile devices so users can read- Earthwise offers, the EGS has up excursions in the field. Ifany EGS members would like to help or have 5 https://en.wikipedia.org/wiki/Main_Page any ideas please contact the author. 25 earthwise — evolution or revolution? map/guide pair should prove most appealing. EGS excursions have been converted from Lothian Geology, Scottish Borders Geology, Ardnamurchan, Ballachullish Igneous Complex and Building stones of Edinburgh; there are also excursions from the joint EGS/BGS Geology in south-west Scotland. Other useful sources are unpublished excursion guides provided by excursion leaders The EGS excursions on Earthwise for actual EGS trips, such as John fall under the general heading of Mendum’s 2005 Banffshire Coast guide Geological walks UK6. This includes and Nigel Fannin’s May 1991 Orkney articles on individual sites, geological field excursion guide. There must be walks or groups of walks formed more of these that we could use. Most into excursions. The site currently of this content is from older guides, has about 160 excursions and walks and the real stars from a presentational (about 1500 individual stops) extracted viewpoint are the recently converted from a range of Society excursion North-west Highlands and Rum guides. guides. There are also descriptions With their colourful maps, diagrams of a number of important geological and photos they point the way to the sites contributed by BGS, initially from standard that can be achieved and the Cainozoic geology and landscape show what we are aiming for with all evolution of north-east Scotland our Earthwise articles. memoir but with scope to add others, perhaps the 1:25 000 Classic areas The aim is to extend content guidebooks, especially now that the coverage from Scotland to other accompanying maps are all on free parts of the UK so if there are any access on the BGS Maps Portal. The other Societies that would like to contribute walks and excursions 6 http://earthwise.bgs.ac.uk/index.php/ please get in touch with the author Category:Geological_walks_UK or the Earthwise Team at BGS. It 26 book review would be a great way of promoting Footnotes will be hyperlinks in the your content and your Society in a online version of EG59 modern and free web-based platform that could integrate with your own Bob McIntosh, British Geological website. Survey: [email protected] Book review Volcanoes and the Making of benefits from a rigorously updated Scotland by Brian Upton. Dunedin text and substantial improvements Academic Press, Edinburgh. Second to both the photos and the figures. edition 2015. Hardback, 248 pp. It has undoubtedly been a labour Price £24.99. ISBN 978-1-78046- of love and, as we would expect 056-7. Also available as an ebook. from an author who has spent his whole career on igneous rocks in general and those of Scotland in particular, it is both authoritative and comprehensive. Igneous rocks ranging in age from almost 3000 million to 46 million years old and spread across the whole of the Scottish mainland and islands are described and interpreted, either as the products of volcanic eruptions or as the plumbing systems and roots of the volcanoes or as the source of their magmas. Few other books aimed at a non-specialist readership provide such reliable up-to-date accounts. The first edition of Brian Upton’s very popular homage to the volcanoes The first four chapters include of Scotland, in 2004, was the first sections on deep time, the tectonic fully comprehensive appraisal of history and make up of Scotland, the Scottish volcanoes since Archibald origin and crystallisation of magmas, Geikie’s Ancient Volcanoes of Great the main types of igneous rocks Britain in 1897. This second edition and the main features of volcanoes 27 book review and their products. All are clearly a challenge for the author and he explained in relatively simple terms does tie himself (and me) in knots and are necessary in order to follow in several places by attempting to the descriptions and interpretations describe the complete geological that constitute the main part of history in a continuous backward the book. Most of this should sequence. It would have been better, be understandable to the target and much easier, to expand the readership, although I have to hope introductory ‘Brief History of Scotland’ that the highly technical diagram (which for some reason ends at the showing isotherms and melting curves Caledonian Orogeny) to give a full on page 10, although beautifully geological history in a conventional, explained on the facing page, doesn’t forward sequence and then describe put off anyone from reading any the individual magmatic events as further. I admire the author’s bravery separate entities, from younger to for including this explanation of older, without the need to make mantle melting. comprehensive but convolute and hence confusing backward links. The chapters dealing with Scotland in particular start with the extensive, very One of Brian Upton’s strengths, well-exposed Palaeogene lava fields and charms, has always been his and dissected central complexes and ability to tap into an encyclopaedic then work backwards in time, through worldwide knowledge of volcanoes the readily identifiable Permo- to find an appropriate modern Carboniferous, Siluro-Devonian and analogue for any ancient feature Ordovician volcanic episodes to less- and then weave a story around it. obvious Proterozoic examples before I particularly like the linking of the discussing, tentatively, the possible Siluro-Devonian caldera-volcanoes surface manifestations of various of Ben Nevis and Glen Coe with Archaean intrusions. This order inferred former calderas above might surprise and even unnerve the Etive Pluton to form a volcanic some readers, but that is because we field comparable in size and former geologists are conditioned to start destructive power to the current at the bottom and work upwards ‘sleeping dragon’ of Yellowstone. in our descriptions. I like Brian’s Such comparisons bring life to the approach, which he does explain and descriptions and add considerably justify early in the ‘Introduction’; it is to their understanding, especially entirely logical for such a ‘forensic’ where they are illustrated by such investigation. It is, however, quite carefully selected photographs, from 28 book review the author’s own collections, from of an unfamiliar term and hope to those of friends and many from other find an explanation. I spotted very internationally recognised authorities. few factual geological errors but There are a few interpretations that there are too many minor glitches raise slight doubts in my mind but my and inconsistencies, especially in attention has been drawn to so many the figures, their captions and in aspects that I had been unaware of references that should have been previously. Most notably, the updated picked up by a scientific edit and/or a and comprehensive review of the good proof check. But hopefully most evolution of the Rum volcano has readers will overlook those. clarified my understanding of that central complex considerably. We will all have our favourite Scottish volcanoes and there really is It has to be said that the book does something in this book for everyone. delve quite deeply into some rather But it will be welcomed in particular technical areas and employs a high by students at all levels and by level of scientific vocabulary, not amateur geologists such as those all of which is explained. So I fear who read The Edinburgh Geologist. that the average ‘farmer, fisherman, They will learn so much about all the tourist and other ……..general fascinating volcanic relics that we are public’, who are declared to be the fortunate to have in Scotland, will target readership in the Preface, will clarify their understanding of volcanic flounder somewhat. A book with that and magmatic processes in general readership would really benefit from and, above all, will thoroughly enjoy a glossary, which is a sad omission. reading an undoubted masterpiece. However, it does have a good index, so one can look for a first mention David Stephenson Stop Press . . . Fossil Hunters Whilst EG was in proof we learnt tetrapod material recovered from the of a forthcoming exhibition Scottish Borders during the TWeed at the National Museum of Project (see EG 53 & 56) and will Scotland, Edinburgh: Fossil certainly be well worth a visit. The Hunters — Unearthing the Mystery of exhibition runs until 14 August and Life on Land. This will feature some of we hope to feature some highlights in the remarkable Early Carboniferous the next Edinburgh Geologist. 29 This issue: No. 59, Spring 2016 1 Editorial ramble Here’s tae us; wha’s like us? 4 John Horne’s Memoir — Signatures from the 1912 & 1914 Assynt excursions By John Mendum 6 Matthew Forster Heddle and the Edinburgh Geological Society By Hamish H Johnston 11 The EGS Long Excursion to Norway 5–12 June 2015 By Beverly P Bergman, Christine L Thompson, Richard A Smith, David Blythe, Stephen Livera, Alison Tymon and Douglas Holliday 18 Volcano Monitoring in Iceland By Rachel Whitty and Isla Simmons 23 Earthwise — evolution or revolution? By Bob McIntosh 27 Book review Volcanoes and the Making of Scotland Cert no. SGS-COC-003231 ISSN 0265-7244