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The Open University Geological Society Wessex Branch Newsletter

Website http://ougs.org/wessex

December 2016

Branch Organiser’s Letter CONTENTS Branch Organiser’s Letter Page 1 Dear All , 25 Sept 2016 Page 2 This feels very strange as it’s my final Branch Two Mendips quarries, 18 Aug 2016 Pages 3-4 Organiser’s letter! Thank you very much for , 7 Oct 2016 Pages 5-6 your support to me over 20 years, as Events , 22 Oct 2016 Pages 7-8 Organiser and then as Branch Organiser. Do look at the adverts on pages 6, 13 and 14 for Minerals guide no. 22 – Tugtupite Page 8 future events. I hope to see you at our AGM Staffa and Ardtun, 16 May 2016 Pages 9-10 and lecture day on the Cretaceous Greenhouse Wessex Branch committee Page 10 World, which is on Saturday 21st January 2017 Book review “ of the Coast” Page 11 in Wool (see page 11). Please let me know if Other organisations’ events Page 12 you plan to come so that we can cater accordingly. Forthcoming Wessex Branch events Page 13 WESSEX BRANCH REPORT 2016 OUGS events listing Page 14 Many thanks to the Wessex Committee and members for making us such a friendly and organising this, even though he could not come, enthusiastic group and to our leaders for and thanks to Ian Williamson for showing us opening our eyes to the wonderful geology such fantastic geology, including Fingal’s Cave! around us. 2016 has been highly successful, I’d also like to thank Mark’s wife Pauline who not only as a branch but also because of our helps Mark with the residential trips. record numbers at the Symposium in . I Thanks go to our Treasurer, Rhiannon Rogers, am pleased to be able to leave the branch in who not only continues to manage our branch such good hands when I stand down at the accounts with excellence but who also had the AGM in 2017. huge task of doing the accounts for the Exeter In 2016 we had an excellent AGM and Lecture symposium. Also thanks to Chris Crivelli for Day with the Theme of “Mull, Mountains and independently checking the sums. Our accounts Mars”. Thanks to our lecturers Ian Williamson, still appear to be healthy and our field trips and Tom Argles and Suzanne Schwenzer plus all events are well attended. Thanks to Hilary who contributed to the fantastic banquet. Barton for a brilliant Footnotes newsletter and to Colin Morley for updating the website and We had five trips led by Alan Holiday during putting so much of interest on it as news items. the year - to Vallis Vale on the Mendips in Also thanks to Colin for accepting the Somerset, Beer in , in nomination as Wessex Branch organiser, I am , Abbotsbury RIGs site in Dorset and sure Colin will be a brilliant Branch organiser , Weymouth in Dorset. Many and I wish him well. thanks to Alan for all his support to Wessex OUGS over all the time I have been a member Best Wishes and before! We also visited Down Farm on Sheila Alderman, Branch Organiser Wessex Cranborne Chase, a Ball Clay works on Purbeck, 4 Yeovil Road, Montacute, Somerset TA15 6XG Lambourn Down in Berkshire, Moons Hill and Tel. xxxxxxxxxxxxxxxxxx Whatley Quarries on the Mendips and Wytch E-mail: [email protected] Farm and in Purbeck. Thanks to our leaders Martin Green, Andrew Deeming, Janet Griffiths Lesley Dunlop, Jill Odolphie, Giles Watts and I am sad to say that Janet Griffiths lost her Suzie Baverstock. Also a very big thank you to fight with cancer on 18th November. She died Jeremy Cranmer for organising such a variety of peacefully in Christchurch Hospice with Ted at day field trips and for planning next year’s her side. Our thoughts go out to Ted and programme. Our residential week was in Mull their family. Sheila Alderman with Ian Williamson; thanks to Mark Barrett for

Wessex Footnotes December 2016 Page 1 WESSEX OUGS FIELD TRIP TO ABBOTSBURY, 25 SEPTEMBER 2016 Leader: Alan Holiday Report by Sheila Alderman Alan Holiday and a group of seven intrepid OUGS Wessex members plus one DIGS enthusiast achieved an amazing transformation of the Dorset Regionally Important Geological Site at Red Lane Quarry in Abbotsbury, Dorset. Between us we were armed with a chain saw, rakes, loppers, secateurs, forks, scrapers, gardening gloves - and a lot of determination. Over the past 20 years I have visited the site many times to help with gradual clearance. It is a very impressive location and in such a beautiful part of the world.

The group take a break Photo by Alan Holiday Job done! Photo by Colin Morley

Alan told us about the geology of the area, which is summarised in an illustrated leaflet produced by Dorset RIGS and available as a .pdf file via http://www.dorsetrigs.org.uk/southwestrigs/abbotsbury/ The Abbotsbury Ironstone forms the earliest strata of the Kimmeridgian Stage in the Upper Jurassic Period. The outcrop is very limited in extent and only outcrops in the locality of the village of Abbotsbury. The deposit is thought to have formed in a marine near-shore environment saturated with iron salts, possibly a barrier bar where gentle wave action rolled the ooids around, building up concentric layers of iron minerals. Attempts to mine the deposits commercially in the 19th century failed as the ore contained too much silica and other undesirable impurities. Although the ironstone was found to be unsuitable for smelting, it was a useful building stone in local houses. Abbotsbury lies in the hollow of a syncline (U shaped fold). Corallian Group rocks (Sandsfoot Grit, Osmington Oolite) form the hills to the south of the village. The Abbotsbury Ironstone underlies the village itself and is seen at the surface on the north side of Chapel Hill to the south of the village, and the fields immediately to the north of the village. The outcrop ceases abruptly where it meets the Abbotsbury Fault. After a rest and lunch, Alan took us for a walk up Blind Lane to see the SSSI slightly higher up in the Jurassic Abbotsbury Ironstone sequence. Then to a tremendous view overlooking Abbotsbury. Making our way through the village, we identified various building stones, including the famous Ham Hill stone that is used in the “poshest” buildings from the Somerset quarry one mile from my home. We also identified a lot of Purbeck, Portland and Corallian building stones, plus a tiny piece of Forest Marble and various pieces of chert in the walls. Others less exhausted than me had a splendid walk up St Catherine’s Hill.

Thanks to Alan Holiday for leading, Jeremy Cranmer View to The Fleet and from Blind for organising the visit and participants for helping! Lane Photo by Colin Morley Sheila Alderman

Wessex Footnotes December 2016 Page 2 WESSEX OUGS FIELD TRIP TO TWO MENDIPS QUARRIES, 18 AUGUST 2016 Torr Quarry and Moons Hill Quarry Leader: Dr Gill Odolphie (Manager, Somerset Earth Science Centre) Report by Andy Mitchell (Torr Quarry) and Helen Phythian (Moons Hill Quarry)

This trip was so popular that Dr Gill Odolphie kindly offered to run it twice, on consecutive days. This report is from the second day, Thursday 18 August 2016. Many thanks to our leader Gill and also to Sean Johnson, Area Geologist with Aggregate Industries UK, who helped us at Torr Quarry. Introduction We assembled at the Somerset Earth Science Centre at 10.30. Two quarries were visited: Torr Quarry (Carboniferous Black Rock Limestone) in the morning and Moons Hill Quarry (Silurian andesite and other volcanics) in the afternoon. The field trip was completed by 16.00. It was a cloudy but dry day - and no mud to worry about! Torr Quarry (also known as Torr Works Quarry and Merehead Quarry) The rock here is Carboniferous Black Rock Limestone with varying levels of manganese and silica; it is therefore quarried for its rock strength, to make various concretes and road base material. It has been used on projects such as Crossrail and the Channel Tunnel. Some 5 million tonnes will be quarried this year. The quarry, which had its origin in Roman times, is situated on the southern limb of the Mendips Pericline – in what was a shallow estuarine depositional environment in the Carboniferous. In one small corner in the upper section of the quarry an unconformity could be seen, with Inferior Oolite (horizontal) overlying the Carboniferous rocks (~40inc). The quarry has a variable clay content within the limestone and some red Trias precipitation is evident in the upper levels. The quarry also has its own local mineralisation in the form of yeomanite

(Pb2O(OH)Cl) and mendipite (Pb3Cl2O2). The quarry, which is operated by Aggregate Industries UK, is currently seven benches deep Field sketch of Torr Quarry Andy Mitchell and bounded by faulting. The 15m benches stand at a 73 wall angle. Plans are in hand to go deeper by another seven benches, though this presents issues for water drainage management. The reserves are currently estimated at 150 million tonnes, which would take production through to 2040. There was historically a 20% wastage but, due to recent washing techniques, old stored scalpings are now sold as road base materials. Moons Hill Quarry After a break for lunch at the Earth Science Centre, Dr Gill Odolphie gave us a talk on the history of the Centre. It was set up in 1997 by Hanson at Whatley Quarry to address the issue of public education (to explain why quarries are needed and why they have to be where they are) and as a hands-on resource for students. From its origins in a portakabin, high demand for this resource led to the setting up of the Somerset Earth Science Centre. All the quarries in Somerset made a financial contribution proportionate to their output in order to further public education in Earth sciences, to inspire people about geology and material usage, to illustrate their sustainable goals and, of course, to draw in future employees. The Centre is now well equipped, generously furnishing us with safety hats, gloves, high visibility jackets and even hammers. We were allowed ‘off leash’ for 45 minutes to examine and hammer rocks at both Moons Hill and Torr Quarries - an unexpected treat and time flew by as we hammered and examined rocks close up.

Wessex Footnotes December 2016 Page 3

After this talk we were taken to Moons Hill Quarry, which is much smaller than the Torr super-quarry but also deeper (150 metres). It produces andesite, which is a premium product and relatively expensive; it is very hard and can be used as a top dressing material for roads up to B roads. It was also recently used for resurfacing the Castle Coombe race track. Andesite has a Polished Stone Value (PSV) of 55 compared with the Carboniferous limestone’s PSV of 45 - meaning it is much less slippery as a road surface. Andesite is so resistant because it has 60% silicate crystals, which stick out on the microscopic scale and increase resistance, making it a premium product for use as the top layer of road stone and, along with bitumen, to make the surface. The quarry is owned and operated by John Wainwright & Co Ltd and is expected to yield andesite until 2028.

Field sketch of Moons Hill Quarry Andy Mitchell

The Moons Hill Quarry andesite (60% silica andesite lavas and ash composition) originates from Silurian volcanoes (425 Ma) which occurred where Australia and New Zealand are now and as part of the Hercynian Mountain Orogeny. It formed at the subduction zone during the closure of the Iapetus Ocean and includes six or seven island arc volcanoes, with thick, viscous lava and ash deposits. A substantial overburden of mudstones and tuffs has to be removed in order to reach the andesite. And the hardness of the andesite entails frequent replacement of crusher parts and the giant truck tyres. All of which adds to the expense of quarrying the rock. The andesite is blasted out using explosives made on site. It is crushed first in jaw crushers and then pestle and mortar crushers before being sieved to grade the fragments according to size. These are then either washed to make clean stone for sale or coated in bitumen which is made on site as asphalt and transported in hot box lorries at 180 °C. We had a most interesting time looking at the andesite, the ashes, chlorite minerals, amygdoloidal andesite and the topography of the quarry; we were also able to collect specimens. Thank you to Gill and Sean for a very interesting and enjoyable day. Moons Hill Quarry Photo by Ian Hacker Andy Mitchell and Helen Phythian

Wessex Footnotes December 2016 Page 4 WESSEX OUGS FIELD TRIP TO WYTCH FARM, DORSET ON 7 OCTOBER 2016 Leaders: Giles Watts (consultant geophysicist) Dr Suzie Baverstock (Communications and External Affairs Team Leader, ) Report by Fiona Hyden Wytch Farm is a unique oilfield for being unobtrusive, sited in an extremely environmentally sensitive area (World Heritage site, SSSI, AONB, Heritage coastline etc), and classed as a super-category field with over a billion barrels of low-sulphur oil in place and over 100 production wells. The oilfield has a recovery rate of 56%, which is high, and there are plans to operate until 2035. Long-reach and horizontal drilling techniques were perfected at Wytch Farm by BP, obviating the need for multiple well sites. At its peak in the late 1990s, the oil field was producing 100,000 barrels per day, and in 2015 this had reduced to 16,000 barrels per day. Perenco took over the field in 2011 and they specialise in oil recovery from ‘end-of-life fields’ (some wells now contain up to 96% water). The field trip started at a viewpoint at Godlingstone, looking north over the Arne peninsula, and Bay on a somewhat gloomy morning. Giles provided an overview of the oil field, though from any vantage point the oil installations are hidden behind coniferous woods on Wytch Heath. The oil field is situated to the north of the Purbeck Fault Zone, a major bounding fault, and oil is extracted from three reservoirs (fig. 1). The lowest, at 1585m, is the Triassic Sherwood Sandstone (braided river deposits exposed at in ). At intermediate depths (924m) is the Lower Jurassic, marine Bridport Sands, exposed at West Bay. The smallest reservoir is within the Middle Jurassic, Fig 1. Wytch Farm reservoirs drilled from vertical, Frome Formation (800m), a pecten bivalve-rich long-reach and horizontal wells. Source: Perenco biostrome that is exposed today along the Fleet at Langton Herring, west of Weymouth. Oil is trapped by overlying impermeable mudrocks and against normal, sealed faults. The Sherwood and Bridport reservoirs are both sourced from the Blue Lias which was buried deeply enough prior to 60Ma to generate oil prior to the Alpine inversion. The was not buried sufficiently deeply here to provide a source kitchen. The hydrocarbons are extracted by beam pump (nodding donkeys) and ESP (a high-tech Archimedes screw), and then separated into four components: (i) gas, to which an odorant is added and then piped to the local Southern Gas grid; (ii) liquid petroleum, odorised and then transported by road tanker; (iii) crude oil, desalted, dewatered and piped to Hamble before being shipped to France (since it is a low-S oil, it is not suitable for processing at the Fawley refinery, which is designed for high-S oil); (iv) highly saline water which is re-injected into the field. We then proceeded to Norden Park and Ride, north of , where we were picked up by coach, generously supplied by Perenco, and Suzie took us on a tour of the installation. The site has been carefully landscaped, the ground surface lowered and screened by dense trees. All the oil installations are painted Van Dyke (dark) brown, deemed the least obtrusive colour (fig. 2), or ironstone green. Fractionation columns are built in pairs, rather than as one tall one, and there are no metallic reflecting surfaces. There is little or no flaring, no steam, and low light pollution. Each Fig 2 Wytch Farm Gathering Station hidden behind installation has a concrete containment wall and trees and painted an unobtrusive van Dyk brown rainwater that collects there is removed by Photo by Fiona Hyden tanker. Formation water recovered during drilling is mixed with sea-water to maintain field pressures, and is then re-injected into the field to sweep the remaining oil towards the wells.

Wessex Footnotes December 2016 Page 5 We visited the Gathering Station (oil piped underground from the various wells), including Well Site X (which dates back to British Gas days), and F and M, which are located on Goathorn Peninsula. The access road to these latter two wells is built on an old track used for transporting ball clay. Well M held the world record for long-reach drilling in the 1990s: M11 is 11.3 km long. An extra heavy drill string was needed in vertical parts of the well in order to drill at the end of the drill stem. After a fascinating morning at Wytch Farm, we re-convened at for lunch before visiting the Kimmeridge oil well (K-1, previously known as Broadbench-2), a lone nodding donkey on the cliff overlooking Kimmeridge Bay which has been in virtually continuous operation since 1961 (fig. 3). It pumps oil from a fractured carbonate reservoir within the Cornbrash (Middle Jurassic) at 512 m depth. The reservoir is only 20m thick and has an average porosity of only 1%, but it is likely that production originates in fracture systems within the Cornbrash and adjacent Kellaways Beds/Oxford Clay and Forest Marble (which is productive at Wytch Farm). It may be that the lower than normal pressures within the Cornbrash reservoir are the result of Fig. 3 Kimmeridge Bay well head visible at the top of sealing the oil within fracture systems prior to the cliff which exposes Kimmeridge Clay Miocene folding; enlargement of these Photo by Fiona Hyden fractures during Miocene folding would reduce the pressure within them. The source rock is the Lower Lias, the same as for Wytch Farm, though the oil is lighter at Kimmeridge, suggesting that some fractionation occurred during migration. K-1 has produced over 3 million barrels of oil, around 80 barrels per day (1 barrel = 35 gallons) during its lifetime, at its peak in the 1970s – but still going! Oil is stored on site and transported by oil tanker. Gradually, the gas to oil ratio is increasing, so eventually, the gas cap will come down to the level of the Cornbrash, break through into the reservoir, and probably abruptly end oil production. Giles finished up the day with an evaluation of the prospectivity in this area of Dorset. There are likely to be some small reservoirs, and there may be gas in the anticline off Durlston Head. Some of the hardier souls in the party then headed off to the beach to look at the Kimmeridge Clay at the end of a gloomy, and rather damp day which had been fantastically enlivened by some amazing, hidden geology and illuminated by our extremely knowledgeable leaders Suzie and Giles – so our grateful thanks to both, and to Perenco for facilitating the visit to Wytch Farm. Fiona Hyden

OUGS WESSEX WEEKEND TRIP TO CHARNWOOD 2016 SYMPOSIUM Friday – Sunday, 2 - 4 June 2017 REFUND Leaders: Ian Williamson and Keith Ambrose If you attended the 2016 Symposium in Exeter and are Two days visiting Charnwood and Bradgate Park. This is a world happy for your share of the renowned area which is famous for its Precambrian fossils, and is where Charnia masoni was found in the 1950’s. surplus to passed on to the 2017 Symposium then you need We will be staying at the Charnwood Arms, from the Friday evening to do nothing. But if you wish to the Sunday morning. The cost of the weekend, on a B&B basis, is £135 claim your refund (of £16 for per person for a single room, £80 per person for a double room and £75 weekend delegates and £8 for per person for a twin room. Evening meals are available locally. day delegates) then please act A deposit of £30 is required by 31 January 2017, with the balance due by 31 January 2017, as by 31 March 2017. Day visitors are also welcome. The charge is £7.50 explained on page 3 of the per day, which must be paid by 30 April 2017. November edition of the national newsletter, available at Full details and application forms (for both residential and day visitors) ougs.org/files/ouc/news/OUGS_ are available at http://ougs.org/events/details.php?id=1698 or Newsletter_2016-11.pdf via Mark Barrett, tel. xxxxxxxxxxx, e-mail [email protected]

Wessex Footnotes December 2016 Page 6 THE ETCHES COLLECTION, KIMMERIDGE, , DORSET Report on a Geological Association Conference Field Trip on 22 October 2016

Leader: MBE Wessex Branch will be visiting the Museum Report by Helen Phythian on 22 January 2017 - see page 13

The Etches Collection is the result of one man’s passion. Over 30 years of discovery and diligent research, dogged determination not just to find and collect specimens, but also to bring to life the amazing stories of the creatures that existed in the Kimmeridgian age. http://www.theetchescollection.org/home We visited the Collection on the day after it opened its doors for the first time. A momentous occasion, after 25 years of negotiations, grant applications and the extraordinary efforts of ‘Team Etches’ but above all the generosity and foresight of Steve Etches MBE in realising the significance of his collection and wanting to share it with the world and future generations of academics and enthusiasts alike. A collection for everyone to enjoy and be inspired by.

The Collection is housed in a striking building, beautifully designed in stone, Sky and frame - Spangle wood and glass, which nestles in the village of Kimmeridge with ease. Approaching the building, one’s attention is immediately absorbed by the mural depicting the stone chimera of a monster pliosaur emerging from a Jurassic sea of textured stone. The darker rock of the pliosaur and the chiselled ‘sea’ background are of one of the most hard-wearing of the Purbeck beds, ironically called Purbeck Feather (Middle Purbeck ref. DB108 in Clements Log), which is quarried at Bell View Quarry near . The design for the body, neck and bones of the pliosaur sculpture used computer-aided design and a cutting machine to obtain a rough shape before hand finishing and polishing. The paler, background rock of the ‘sky’ and the mural frame are of honed Spangle Bed, which is both beautiful and hard wearing. It is quarried, from the Portland Beds at St Aldhelms Quarry, Stone mural . Fossils, including the outside building Pliosaur skeleton, body and darker bivalve Myophorella, litter this bed and each Photo courtesy of Andy background - Purbeck feather is infilled with calcite crystals, which Webster, Haysom Ltd sparkle and pick out the remains of marine organisms caught in time. The anticipation was tangible as the GA group waited in the naturally appointed and beautifully light atrium with life-size murals of Kimmeridgian marine life. Steve Etches was greeting and talking with everyone. The pliosaur mural that drew us into the museum illustrates beautifully the aspect of bringing the fossils out of their stony stillness into 3D and the moving forms on giant CGI screens above the displays give insights into the past ecology of the organisms. The Etches Collection comprises superbly prepared fossil remains of ichthyosaurs, squids, fish, shells, plesiosaurs, pterodactyls, ammonites and even three lots of ammonite eggs - a world first (among others). A paper has been published on the CAT scan evidence which show tubercles like those found in modern cephalopod eggs. The collection houses world-class fish and pterosaur remains. It has the CGI screens bring Kimmeridgian fossils largest collection of pterosaur bones and the first to life Photo by Ian Hacker rhamphorhynchoid pterosaur in Britain, which is as yet still emerging from its stony grave. Soft part preservation is rare, yet Steve has superbly prepared cartilaginous shark remains showing the male claspers and even female sperm receptacle ducts.

Wessex Footnotes December 2016 Page 7 The theme that came out for me was: Predation. Steve pointed out the evidence: hooked feeding apparatus of squids; huge, serrated, pointed teeth; bite-marks in bones; chunks missing from ammonites; and stomach contents showing an ichthyosaur’s last meal. He used this evidence to paint a picture of terrifying predators powering through Jurassic seas in pursuit of prey. CGI of marine predators menace above the innocent spectator, completing the tableau. The museum is an outstanding, world-class resource and now that it has this status, more researchers will be attracted, further research and more scientific papers produced, more knowledge linked and shared - thus expanding our knowledge, understanding and awe Steve Etches with some of his fish fossils of Kimmeridgian life. Photo by Ian Hacker The museum also includes a state-of-the art prep laboratory which is glass-fronted, enabling visitors to observe the prepping process, watch the techniques and follow the story of the emerging fossil, thereby understanding more of its ecology and significance. Thank you very much to Steve and the Etches Collection Team for hosting us and making the GA so welcome. Most of us will be back for more. Helen Phythian References and acknowledgements The Etches Collection website (including a down-loadable brochure): http://www.theetchescollection.org Grateful thanks to Mark Haysom (Haysom’s Ltd, Kingston Road, Langton Matravers, Dorset, BH19 3JP) for providing details of the methods and materials used in the creation of the mural. Mark worked with the architects (Kennedy O’Callaghan Architects) on the design of the mural and the choice of stone; David Peddle carried out the computer work and masonry.

SIMPLE GUIDE TO MINERALS 22 - by Colin Morley

TUGTUPITE Na4(AlBeSi4O12)Cl Tugtupite was named after its type locality and was found in an albite vein in Tugtup, Attakoorfia in Greenland in 1962. It is quite a complex mineral with many possible ingredients, as you can see by the alphabet soup in the brackets. To complicate matters there is a long list of possible impurities from Fe, Mg to S and K. Not many letters left unused with this one, is there? It was found in hydrothermal veins and is probably a replacement mineral. It has since been found in Quebec and the Kola peninsula. It is a beryllium aluminium tectosilicate and a member of the silica-deficient feldspathoid group. It occurs in high alkali Tugtupite intrusive igneous rocks and is often found with sodalite. In natural light (above) and UV light (below) It is generally found as a massive lump, as in the picture. Specimen in the Sun City Rockhounds collection Tugtupite has a tetragonal crystal system and a hardness Photos by Colin Morley of just 4 on the Moh scale. It streaks white and the lustre varies from sub-vitreous to dull. The cleavage is distinctive and fractures usually look like tiny steps. The colour is normally a pinky-white to pink but with all those possible impurities other variations are possible. Remember that colour is a poor indicator in minerals. That doesn't sound too exciting but under short wave UV light it shows as a bright magenta-red to pink and blue. The colour under UV is quite distinctive. I can't think of another mineral showing that colour under UV. Colin Morley

Wessex Footnotes December 2016 Page 8 WESSEX OUGS WEEK IN MULL, SCOTLAND: 15 – 20 MAY 2016 Leader: Ian Williamson STAFFA AND ARDTUN (Monday, 16 May 2016) Report by Alan Mack The morning was dry with occasional sunny spells; more importantly there was very little wind, since a calm day would mean flat seas for our voyage to the Isle of Staffa. We set off in eager anticipation of the day ahead and were soon speeding westwards the few miles to Fionnphort and the boat that would take us to Staffa. Our objective for the day was to study the sequence of volcanic and associated sedimentary rocks of the Palaeogene Staffa Lava Formation on Staffa and at Ardtun on the Isle of Mull. The journey by boat took us 45 minutes. It was a delightful start to the day, with a calm sea. As we neared Staffa we could see the features so familiar from photos Preparing for the day ahead: outside our and videos. The boat steered close to the mouth of accommodation near Bunessan on the Isle of Mull Fingal’s Cave on the south of the island - a good vantage Photo by Alan Mack point to admire the Great Face. Staffa Entablature Fingal’s Cave The Great Face consists of two main bedding features resting on a base of sedimentary rocks. Despite appearances, it is generally accepted that the formation was formed from one eruption flow, the different features being due to different cooling histories. After the tholeiitic lava flowed over the base sedimentary rock (reworked volcanic breccias) the top cooled relatively quickly by contact with air and by rainfall percolating down through the flow, Colonnade forming the irregular structures of the entablature. Volcaniclastic breccias The lower part of the flow cooled much more slowly by contact with existing sedimentary rock beneath and the entablature above and as the lava cooled it contracted, forming the regular columnar jointing structures of the colonnade. Fingal’s Cave and the Great Face Photo and annotations by Alan Mack This flow and others on Staffa and on Mull are part of the Staffa Lava Formation (c. 55Ma) which itself is part of the much larger North Atlantic Igneous Province (NAIP). Around this time the Laurentian and Eurasian plates were separating present day Scotland from Greenland. The volcanic activity and

associated CO2 emissions of the NAIP may have contributed towards the Paleocene–Eocene Thermal Maximum when global temperatures increased by 5–8 °C. There was only room for one boat at the landing stage at Am Buachaille so after we disembarked our vessel cast off and anchored a short distance away to wait while we explored the island for an hour or so. Fingal’s Cave was close by, a short walk along a path Fingal’s Cave Photo by Alan Mack across an amazing natural pavement of columnar jointed basalt. What an awesome experience it was to walk into the cave as far as we dared.

Wessex Footnotes December 2016 Page 9 We walked back to the landing stage and clambered up a steep staircase to reach a grassy top. We spent an hour exploring the island before returning to the boat and the journey back to Fionnphort. After lunch on the shore at Fionnphort we headed off to our next location, Ardtun and the famous Leaf Beds. Ardtun The Ardtun Leaf Beds, dated at c. 54 Ma, are formed from paleosols and associated flora that existed just after the lava flows that we had seen earlier on Staffa. The sedimentary sequences here provide evidence of interludes between eruptions of the Staffa Lava Formation, when erosional processes formed rich soils in Our leader Ian Williamson above the landing which a wide range of flora flourished. The exceptional landing point on Staffa Photo by Alan Mack preservation of these flora makes this an internationally renowned location. The environment then was suitable for familiar tree species such as plane, hazel, oak, alder as well as now almost extinct ginkgo. The sedimentary rocks here are mainly composed of siliciclastic beds of poorly sorted material within which are thin layers of limestone and three carbonaceous mudstone-siltstone units (the Leaf Beds). The Leaf Beds have been thoroughly worked over and quarried out but some of us found a few fragmentary remains in fallen blocks and spoil.

Image available at:

http://www.hunt search.gla.ac.uk/ cgi- bin/foxweb/hunt search/DetailedR esults.fwx?collect ion=geology&Se archTerm=Pb818 &reqMethod=Lin k&browseMode= Exploring the Ardtun Leaf Beds on Ian explaining the sedimentary structures Photo by Alan Mack associated with the Ardtun Leaf Beds Photo by Alan Mack Rhamnus major, a fossil leaf from the Ardtun Leaf Beds, about 8cm long Detail of a photograph reproduced by kind permission of the Hunterian Museum, Glasgow. © The Hunterian, University of Glasgow 2016.

As an example of the exquisite preservation of specimens found at this location I have included a photo of Rhamnus major, held by the Hunterian Museum, University of Glasgow. Alan Mack

WESSEX BRANCH COMMITTEE CONTRIBUTIONS TO THE Branch Organiser Sheila Alderman [email protected] NEWSLETTER Treasurer Rhiannon Rogers [email protected] Day Trip Organiser Jeremy Cranmer [email protected] Is there anything you Newsletter Editor Hilary Barton [email protected] would like to tell or ask Residential Trips Mark Barrett [email protected] other members? All Website Manager Colin Morley [email protected] contributions welcome. Librarian Jeremy Cranmer [email protected] Hilary Barton, Editor [email protected] Ordinary members: Ian Hacker, Tony Loftus, Jane Mead, Linda Morley, Marion Phillips, Mike Grover (co-opted), Gill Michaels (co-opted).

Wessex Footnotes December 2016 Page 10 BOOK REVIEW Sam Scriven’s “Fossils of the ” Reviewed by Mark Barrett Samuel Scriven “Fossils of the Jurassic Coast” The Jurassic Coast Trust, 2016 £14.95 (ISBN: 978099311071) Available from bookshops and http://jurassiccoast.org/product/6264/ I have recently bought a copy of this book by Sam Scriven, who has led many of our annual fossiling trips on the Dorset coast. It is a very difficult task to write a book on a subject that not only appeals to the layman with no prior knowledge of the topic but also to those of us who have a deeper interest. The author has managed to do this admirably. The book is divided into four parts. Parts One and Two deal briefly with an overview of the Jurassic coast and how fossils are formed, plus the history of the Earth prior to the Mesozoic. The bulk of the book is contained in Part Three, which takes you on a journey through time, starting at the western edge of the Jurassic Coast in the Triassic Pebble Beds and finishing at the eastern edge in the Chalk Group at . There are some quite stunning photographs and illustrations of fossils throughout, some of which were provided by our group member Alan Holiday. As we travel through time, the various ecosystems within which these creatures lived are explained in a manner that brings them to life. Two particularly striking examples are the coverage of the Pliosaur, now displayed in the Dorset County Museum, and the Etches Collection at Kimmeridge. [For an update on the latter, see pages 7-8. Ed.] An innovative feature is six suggested itineraries for fossil walks along various parts of the Jurassic Coast which give details of local museums and other geological points of interest that you may like to visit while you are in the general area. In this section, some basic principles of geology are introduced in layman’s terms (for instance biostratigraphy and the formation of oil) in a manner that holds the interest of all readers irrespective of their knowledge. Part Four deals with fossil collecting. It starts by giving a brief history of fossils, commencing with the myths surrounding them prior to the 19th century, before people like revealed them for what they actually were - plants and animals from deep time. There then follows a comprehensive explanation on how to collect, prepare and keep fossils. At the back of the book is a useful list of websites and contact numbers for various museums and groups, together with a pull-out poster that illustrates the tree of life of the Jurassic Coast. This book is very good value for money at £14.95 and I would recommend it for anyone who has an interest in fossils, irrespective of age, particularly if they intend to visit the Jurassic Coast. It would make a great Christmas present! Mark Barrett

WESSEX OUGS AGM

RICHARD THORPE MEMORIAL PRIZE AND LECTURE DAY AWARDED TO TERRI NEWTON The Cretaceous Greenhouse A cheque for £100 is awarded to the student who produces the World most outstanding work in S339 Understanding the Continents. 10.15am to 4.00pm Richard Thorpe was a hard rock geologist and member of the Saturday 21 January 2017 Open University Earth Sciences Department who died on an D’Urberville Centre, Wool, Dorset OUGS trip to Lundy in 1991. He co-wrote The Field Description Lectures by Prof. Andy Gale, Prof. Hugh of Igneous Rocks with Geoff Brown, former head of Earth Jenkyns and Dr Peter Skelton. Sciences, and was President of OUGS from 1983 to 1984. The whole day, including a buffet lunch, The winner for 2016 is Terri Newton of the Wessex Branch. is free of charge. Non-members welcome So, on behalf of Wessex branch – (but please don’t vote at the AGM!). Please contact Sheila Alderman if you CONGRATULATIONS TO TERRI plan to attend on [email protected]

Wessex Footnotes December 2016 Page 11 OTHER LOCAL EVENTS – PLEASE CONTACT THE ORGANISERS DIRECT

GEOLOGY LECTURES AT DORSET COUNTY MUSEUM LULWORTH RANGE WALKS High West Street, Dorchester DT1 1XA 14 Dec 2016 Ignite! (Christmas party: short talks, mince pies, wine) & VILLAGE For information on opening times 11 Jan 2017 What is a species? (Dr John Whicher) tel. 01929 404819 8 Mar 2017 The Late Triassic Mass Extinction Event (Prof Richard Twitchett) OPEN EVERY DAY OVER HOLIDAYS Lectures start at 7pm. All welcome. Free, suggested donation of £3. 17 December 2016 – 4 January 2017 Further information: tel. 01305 262735. 8 - 23 April 2017 http://www.dorsetcountymuseum.org/events 29 April – 1 May 2017 27 May – 4 June 2017 22 July – 3 September 2017 16 December 2017 – 3 January 2018 DORSET GEOLOGISTS’ ASSOCIATION GROUP (DGAG) www.dorsetgeologistsassociation.com OPEN EVERY WEEKEND EXCEPT: 10 Dec 2016 Christmas Workshop, Broadmayne 10-11 December 2016 14 Jan 2017 AGM and presentation on Portland storms, Wool 14-15 January 2017 23 Mar 2017 Inferior Oolite (Bob Chandler) 11-12 March 2017 31 Mar-3 Apr 2017 Forest of Dean/Malverns (Noel Donnelly) 1-2 July 2017 7-8 October 2017 OUGS members welcome but check beforehand that spaces are 18-19 November 2017 available. Contact: Doreen Smith tel. xxxxxxxxxxxx or e-mail 9-10 December 2017 xxxxxxxxxxxxxxxxxxx

DIGS: Dorset’s Important Geological Sites Group NATURAL SCIENCE SOCIETY More details from Alan Holiday: xxxxxxxxxxxxxxxxxxxxxx AND MUSEUM http://www.dorsetrigs.org.uk 39 Christchurch Road, Bournemouth BH1 3NS If you would like to be kept informed of forthcoming http://www.bnss.org.uk conservation sessions, please contact Alan, who will be happy The Society covers all branches of natural science, to add your name to his e-mail circulation list. including geology and palaeontology. It has an 12 Dec 2016 Kingbarrow, Portland extensive, and very impressive, collection of fossils, 27 Jan 2017 West Hill Chalk Pit, Corfe Castle rocks and minerals which can be viewed during the 7 Feb 2017 Whitecliff, Parkstone Bay, Poole CHRISTMAS OPEN DAYS: 10am-4pm, 20, 22, 27 & 29 Dec 2016 (free entry, donations welcome) DORSET BUILDINGS GROUP Forthcoming lectures include John and Sue Rowntree, xxxxxxxxxxxxxxx 4 Feb 2017 The (Prof. Vincent May) 28 Feb 2017 Rocks from Space (Ron Westmass) The Group aims to promote the preservation of Dorset’s building traditions and so takes a practical interest in YOUNG EXPLORERS’ CLUB (geology and more!) building stones and local geology. Winter lecture are held For children aged 7 to 12. £4 per child per meeting. in Holt Village Hall, Dorset; admission £5 (including cake!). 14 Jan 2017 Rocks and Fossils 8 Jan 2017 The Lottery-funded building programme at 11 Feb 2017 Maths and genetics Dorchester Museum (Jon Murden) 11 Mar 2017 Astronomy 5 Feb 2017 The archaeological excavations at Corfe Castle www.bnss.org.uk/about/young-explorers and Chedworth Villa (Nancy Grace)

RUSSELL SOCIETY, SOUTHERN BRANCH SOUTHAMPTON MINERAL & FOSSIL SOCIETY http://www.russellsoc.org/ http://www.sotonminfoss.org.uk Gary Morse : xxxxxxxxxxxxxxx tel. xxxxxxxxxxxxx Gary Morse : xxxxxxxxxxxxxxx tel. xxxxxxxxxxxxx For anyone interested in minerals, the Branch runs summer field trips plus winter lecture meetings on the second Thursday of the The Society runs indoor meetings, field trips and other month at Wyvern Technical College, Fair Oak, Eastleigh, Hants. activities. Monthly evening meetings are held at The Friends' Meeting House, Ordnance Road, Southampton 15 Dec 2016 The Cryolite Mine, Greenland (Michael Doel) (guests welcome). 12 Jan 2017 AGM plus talks on classic minerals 9 Feb 2017 Mineral Fakes and Forgery (Gary Morse) 15 Dec 2016 Recenseo Annus 2016 (Gary Morse)

COMMUNITY LECTURES AT THE THOMAS HARDYE SCHOOL, DORCHESTER 12 Dec 2016 Extrasolar planets (Dr Nathan Maine) 8 Feb 2017 Discovering Dinosaurs in Britain (Dean Lomax) Lectures start at 7pm in the School Theatre. Tickets are free (donations welcome) but must be pre-booked. www.thomas-hardye.net/pages/information/Community%20Lectures.php

Wessex Footnotes December 2016 Page 12 WESSEX BRANCH EVENTS – DETAILS

Kimmeridge, Dorset Sunday, 22 January 2017

THE ETCHES COLLECTION AND KIMMERIDGE BEACH

with Steve Etches MBE To book a place, contact: Jeremy Cranmer at [email protected] or tel. xxxxxxxxxxxx Steve Etches is a local Kimmeridge fossil collector and expert. Over the last 30 years he has discovered, collected and researched over 2,000 incredible late Jurassic Kimmeridgian fossils. His collection contains the

most extensive and finest fossil specimens ever found in the Kimmeridgian Clay Formation. The collection is now on display in a brand new (October 2016) museum in the village of Kimmeridge, which will take the visitor on a journey through underwater life 150 million years ago. Steve will show us the museum in the morning and we shall then go on to the beach at Kimmeridge Bay with him. The Branch’s Day of Lectures is the previous day (21 January) at nearby Wool.

The all-in cost is £13.00. This includes the entry ticket (£8.00) to the museum which remains valid for a year. [See the report on the new museum on pages 7- 8 of this newsletter. Ed.]

Vallis Vale & Tedbury Camp, Somerset Sunday, 19 February 2017

INTRODUCTION TO GEOLOGY: VALLIS VALE AND TEDBURY CAMP with Alan Holiday

To book a place, contact: Jeremy Cranmer at [email protected] or tel. xxxxxxxxxxxx Alan Holiday has taught geography and geology in Weymouth since 1971. He is now retired but spends much of his time leading field trips! Over the years he has been involved in a range of OUGS activities as well as now being Chairman of the DGAG and Dorset RIGS group. The trip is aimed at OU students who are beginning to study geology. It will also be of interest to students studying environmental subjects as there is evidence of sea level change. This site is a great location to extend the knowledge gained on the first Introduction to Geology field trip to Bowleaze Cove on 13 November last year. However, while it is complementary, it is not necessary to have attended the first one. We will study the Carboniferous limestone and its unconformable relationship with the overlying Triassic and Jurassic rocks, providing evidence for the effects of the Variscan Orogeny. The famous De la Beche unconformity is a classic. Recent conservation work on Tedbury Camp has exposed the structures for all to see. The 2 km walk is mostly flat, with a slight incline to Tedbury Camp and a steep incline with steps to return to cars.

Winchester area, Hampshire Friday, 10 March 2017 HYDROGEOLOGY OF THE CHALK with David Bone To book a place, contact: Jeremy Cranmer at [email protected] or tel. xxxxxxxxxxxx

A growing demand on the supply of clean water is balanced by ever increasing constraints on the discharge of wastewater to the environment. Courtesy of Southern Water, we start with a visit to the historic Twyford Water Treatment Works to understand the processes behind water abstraction from the Chalk aquifer and putting it into supply. The visits will be complemented at lunchtime by talks from the Environment Agency on how these activities interact with the hydrogeology of the Chalk and the environmental constraints that need to be taken into consideration. In the afternoon, we visit Morestead Road Winchester Wastewater Treatment Works. Here wastewater is treated to a high standard before discharge and recharge of the Chalk aquifer. This is the largest wastewater discharge to groundwater in the UK. This expedition should be of interest both to OU students studying environmental science and geologists.

MEMBERSHIP SUBSCRIPTIONS DUE 1 JANUARY 2017 2017 rates are £22.00 for Full and Associate members and £32.00 for Joint members. Please ensure you change your standing order (with a payment date of 1 January) and cancel the out of date one. You can find a Standing Order Mandate form with your OUGS Newsletter and on the website.

Wessex Footnotes December 2016 Page 13

THE OPEN UNIVERSITY GEOLOGICAL SOCIETY, WESSEX BRANCH – FORTHCOMING EVENTS This listing covers events in the Wessex area and general Society events. However, members can attend events organised by any OUGS branch - the full listing is at http://ougs.org/events/ Wessex Branch field trips Places are filled on a first come, first served basis. Non-members are welcome to attend events, but members will be given priority if places are short. Please contact the organiser to confirm details and to ensure there are spaces. Packed lunches, hard hats, strong footwear and waterproofs are usually required plus reflective clothing in working quarries. Please take note of the safety issues, which the leader will outline at the start of each trip. For day trips there is usually a charge of £2.50 per person to cover expenses. Events shown in italics are joint ones – please contact the host organizer as shown. Last-minute contact on the day, if you’re not coming or late: Jeremy’s mobile 07531 318314

DATE EVENT LEADER(S) CONTACT Tuesday, 7.30pm Lecture by Prof. Jane Francis OUGS Oxford Dr Helen Craggs 6 December 2016 “When Antarctica was Green” Branch xxxxxxxxxxxxxxxxxx Wessex Branch AGM and lecture day Sheila Alderman Saturday (“The Cretaceous Greenhouse World”) Sheila Alderman [email protected] 21 January 2017 Wool, Dorset tel. xxxxxxxxxxxx Sunday The Etches Collection, Kimmeridge Steve Etches MBE 22 January 2017 (£13 to include annual pass to museum) Introduction to Mendip Geology, Vallis Sunday Vale & Tedbury Camp, Somerset Alan Holiday 19 February 2017 (suitable for those new to field geology) Jeremy Cranmer [email protected] David Bone with tel. xxxxxxxxxxxx Friday Hydrogeology of the Chalk Environment 10 March 2017 Winchester area Agency & Southern Water Sunday Environmental and sea level change Jeremy Cranmer 23 April 2017 Weymouth Bay, Dorset Tues - Sat Jane Schollick Isle of Wight Dr Pete Webb FGS 2 – 6 May 2017 xxxxxxxxxxxxxxxxxx Jeremy Cranmer Sunday Geology and geomorphology Kelvin Huff [email protected] 7 May 2017 Studland, Isle of Purbeck, Dorset tel. xxxxxxxxxxxx Fri – Sun OUGS AGM (13 May) & Social Weekend OUGS Secretary OUGS 12 -14 May 2017 Milton Keynes [email protected] Fri – Sun Keith Ambrose Mark Barrett Weekend in Charnwood 2 – 4 June 2017 Ian Williamson [email protected] Sunday Climate and environmental change in the Jeremy Cranmer Jeremy Cranmer 23 July 2017 Cretaceous, , Dorset [email protected] Fri- Sun OUGS Symposium OUGS East of Michael Perkins 18–20 August 2017 Edinburgh Scotland Branch xxxxxxxxxxxxxxxxxx Jeremy Cranmer Sunday Geology and fossil hunting Sam Scriven [email protected] 24 Sept 2017 Lyme Regis tel. 01305 267133 Tues - Fri Dr Ralph Nichols Kathy Stott Residential trip to Jersey 3 – 6 October 2017 Robert Waterhouse xxxxxxxxxxxxxxxxxxxxx Sunday Conservation session at a RIGS site Alan Holiday 15 October 2017 Jeremy Cranmer [email protected] Sunday Introduction to Geology, Bowleaze Cove Alan Holiday tel. xxxxxxxxxxxx 5 November 2017 (suitable for those new to field geology)

INFORMATION ABOUT INSURANCE ON FIELD TRIPS AND EVENTS Each person attending a field meeting does so on the understanding that he/she attends at his/her own risk. The OUGS has Public Liability Insurance Cover for field and indoor meetings, but Personal Accident Cover and Personal Liability cover remain the responsibility and personal choice of the participant. There may be an element of appropriate cover included in house insurance or in travel insurance: although OUGS activities are not particularly dangerous, members are advised to check whether exclusions apply to activities in which they plan to participate in case they wish to arrange further cover. Annual travel insurance may be the best solution for any member who regularly attends field events: this again is a matter of personal choice. Please note however that all members participating in overseas events will be required to have travel insurance for the duration of the event: this is so that participants are covered for Medical, Repatriation and Personal Liability expenses. The Personal Accident element remains the personal choice of the member and again members are advised to check exclusions so that they can make an informed decision about the cover. Sheila Alderman, Branch organiser Jeremy Cranmer, Branch Day Events Organiser

Wessex Footnotes December 2016 Page 14