The Open University Geological Society Wessex Branch Newsletter

Website http://ougs.org/wessex

December 2015

CONTENTS Branch Organiser’s Letter Page 1 Season’s Greetings fossiling, 13 Sept 2015 Pages 2-3 to all readers , 23-25 September 2015 Pages 4-9 Hope to see you at our AGM and Rock of Ages, a note by Tony Cross Page 9

day of lectures in Wool on Minerals guide no. 17 – Musocovite Page 10 Saturday, 23 January 2016. Wessex Branch committee Page 10 OUGS Symposium 2016, Exeter Page 11

Other organisations’ events Page 12 2016 AGM notice and programme Page 13 Branch Organiser’s Letter Forthcoming Wessex Branch events Page 13 Dear All OUGS events listing Page 14 I hope you have enjoyed your geology over the past 12 months. Do look later in the newsletter many of them the only concrete involvement for future events and in particular the advert for they have with the branch, we have decided to the AGM and lecture Day on 23rd January 2016 continue to do so. The cost of printing and in Wool near Wareham (page 13) and the postage is just covered by our branch grant. th th Symposium in Exeter 8 to 11 July 2016 Our branch over the last 20 years has ended up (page 11). Thanks very much for the offers of with a surplus in the accounts so we are help with the symposium. The cut-off date for sponsoring the cost of the boat along the the symposium is much earlier than in previous Heritage Coast for the symposium in 2016 as years due to our contract with Exeter University well as paying for one of our very supportive so book early to ensure you are not field trip leaders, Alan Holiday. disappointed. Best Wishes I look forward to meeting our new members and catching up with as many of you as Sheila Alderman, Branch Organiser Wessex possible during 2016. In the meantime, here is xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx my report for 2015. Tel. xxxxxxxxxxxxxxxxxxxxxxxxxxxx E-mail: [email protected] WESSEX BRANCH REPORT 2015 We have had 16 successful events since January including the AGM and lecture day, local field trips and residential field trips. We find that by having something each month members get in the habit of attending events. The programme for 2016 is nearly finalised – we want to be ahead of things because the committee, alongside SW and Severnside branches, continues to be busy organising the Symposium in Exeter 8th to 10th July 2016. Very many thanks to the Wessex Committee and members for making us such a friendly and interesting group. We still post Footnotes to almost 60% of our members and, as this is for Colin Morley et al at the Grand Canyon October 2015 Photo by Chris Crivelli

Wessex Footnotes December 2015 Page 1 WESSEX OUGS FIELD TRIP TO LYME REGIS, 13 SEPTEMBER 2015 Lower Jurassic Geology of Monmouth Beach Leader: Sam Scriven Report by Heather Sloane Twelve OUGS members met Sam Scriven, Earth Science Advisor, at the Lyme Regis Lifeboat Station on a clear, sunny morning. It was just possible to view the range of the Jurassic Coast from the eastern boundary with the Cretaceous at distant , passing the remnants of ice age deposits that formed , crumbling blue cliffs with the sandstone-topped , to the boundary with the Triassic at Bay in the west. We set off westward across the former site of the Lyme Regis Cement Works to explore the Lower Jurassic rocks and fossils, find the Triassic boundary and view evidence of Lyme Regis’ industrial past. Lower Jurassic geology formed around 200 Ma, when shallow seas at the western edge of the Tethys Ocean covered the British Isles, located in tropical latitudes. At this time floods of basalt erupting at the Atlantic Ridge were starting to separate the continents of Eurasia and Laurentia. The climate was less arid than the Triassic, so sea levels started to rise. The cliffs show significant rhythmic bands of limestone, marl and shale as evidence of fluctuating sea levels associated with this tectonic activity. Recent theories also attribute the band variance to climate changes influenced by Milankovitch Cycles. Rhythmic banding Photo by Linda Morley Blue Lias limestone formed in tidal seas, supporting both vertebrate and invertebrate marine ecosystems. Slabs were seen containing multiple bivalves (many fragmented), ammonites and belemnites, also trace fossils as evidence of benthic and pelagic ecosystems. Mudstone layers have yielded fossils of whole fish, ichthyosaurs and plesiosaurs that settled on the sea bed. Lack of scavengers and deposition in still, cold waters created low-oxygen conditions that preserved specimens with soft parts, including skin and intestine content, as well as scales and skeletal structure. Shale beds are fissile, parallel layers of fine-grained clay, dark grey in colour indicating anoxic conditions and containing no evidence of benthic fauna. There was a considerable amount of beef-in-shale on the beach in varying thicknesses which provided specimens showing its formation. “Beef” is the name given to dark calcareous crystals growing between layers of shale, which have the fibrous appearance of beef. The crystals form as interlocking cones that frequently appear as circular indentations in the original shale layer, which are often mistaken for fossils. Cone-in-cone “beef” As the sea receded, an extensive Photo by Linda Morley limestone slab became exposed approximately 300m along the beach. This supported some rusting steel rails and fixings, with blocks or pulley reels lying as beach debris. These remain from a tramway and winch mechanism of an aerial ropeway used to move material quarried from the cliff for the production of cement. In 1756 John Smeaton, an engineer from Leeds, found that lime, when ground and burnt with a quantity of clay, produced a “water cement” that set underwater. Clay adds silica and alumina to lime burnt to produce cement which expands into cracks; this repels moisture and is now known as Hydraulic Cement. This innovative product was used in concrete for docks, harbours, bridges and Tram rails Photo by Linda Morley lighthouses as well as for render for damp proofing. In 1855 a cement factory was built on Monmouth Beach to produce hydraulic cement. Industrial Lyme: Paper 61 provides maps showing the extent of the cement works, with many photographs and additional information from historical records of Lyme Regis. This includes records of merchants trading clay for bricks and pottery, Blue Lias for building materials and lime burners, while both were utilised for cement.

Wessex Footnotes December 2015 Page 2 Industrial removal of limestone and clay from the beach has undoubtedly contributed to the rapid cliff retreat, which is often wrongly blamed on fossil collectors. We continued along the beach to bed 29, the Ammonite Pavement, where Sam pointed out some features of these creatures in the limestone bedding:  Females are large, males are smaller.  Maturity can be determined by the number and width of the chambers; evidently some ammonites were mature.  Smaller, inner, gas-filled segments of the coil were walled off to give buoyancy. Long, outer segments housed the mollusc.  There are fewer ammonites to the west, in the same bed. We discussed possible reasons for so many ammonites to expire in this location:

 Specimens are whole, so no evidence of storm surge or tsunami. Ammonite pavement  Mass breeding ‘orgy’. Photo by Linda Morley  Lagoon cut off by climatic change.  Lagoon cut off by tectonic activity, eg closure of the Tethys Ocean.  Lack of food (plankton) attributed to a break in the eco-system: o Meteor impact, the seas became acid and plankton were first to suffer. o Atmospheric dust, lack of light for photosynthesis of plankton. Sam pointed out that some of the limestone beds showed a variety of extension cracks, evidence of movement within the layer. Suggestions for this include:  Unloading of upper layers by excavation and erosion.  Difference between competent and incompetent materials in different beds.  Clay swelling and contracting with changing temperature and climate.  Water pressure of storms.

The beach also showed eroded boulders as evidence of Cretaceous Extension cracks geology, fallen from inland by landslides. These included Photo by Linda Morley greensand, chalk and chalky sandstone containing bivalve, brachiopod and crustacean fossils. Seven Rock Point is the peak of a syncline; this is evident as the orientation of bed erosion is noticeably reversed beyond this point. We progressed around the point towards Pinhay Bay and looked back to view the rhythmic change of sedimentary beds from the cliff to the shore line. At our furthest point, Pinhay Bay, Sam pointed out the distinct White Lias beds extending throughout the lower beds at the base Rhythmic banding Photo by Linda Morley of the cliff. This indicates lagoonal deposition of the Upper Triassic when sea levels started to rise and shallow seas covered the arid desert of Pangaea; the more typical red-bed Triassic sandstones can be seen further to the west. Fossils found on Monmouth Beach included small ammonites, a Junction between White and vertebra (possibly an ichthyosaur cervical or tail), chert sponges and Blue Lias Photo by Linda Morley fine examples of “beef” crystallisation. The rain held off, so we had another splendid Wessex field day. Our thanks go to Sam Scriven for his guidance and sharing his knowledge of the area. Heather Sloane References 1 Bull, Richard. Industrial Lyme: Paper 6. The Cement Industry in Lyme Regis & Charmouth. May 2015 http://www.lymeregismuseum.co.uk/images/stories/research/6_cement_industry_in_lyme.pdf

Wessex Footnotes December 2015 Page 3 WESSEX OUGS FIELD TRIP TO ANGLESEY, 23-25 SEPTEMBER 2015 Leaders: Dr Margaret Wood, Stewart Campbell and David Wilson Reports by Tony Loftus, Kelvin Huff, Gwenda Brewer, Lyn Relph and Alan Holiday

23 SEPTEMBER 2015 (DAY 1): MARQUESS OF ANGLESEY’S COLUMN & LLANDDWYN ISLAND The day began with an explanation of Ocean Plate Stratigraphy at our hotel by field trip leader Dr Margaret Wood, Managing Director of GeoMôn (Môn is the Welsh word for Anglesey). A helpful overview is at https://www.youtube.com/watch?v=03F46B4J_XQ In the late Precambrian most land was located near the South Pole and “Icehouse World” conditions were extensive e.g. the Gaskiers glaciation at 580-555 Ma. Avalonia formed a volcanic island arc on the northern margin of Gondwana. Anglesey approached Avalonia towards the south east. Our first site was the Marquess of Anglesey’s column – or rather the famous blueschist in the vicinity. In the best tradition of field trips, a thick covering of green moss and algae obscured the showcase rock. Close examination revealed still visible pillows despite the journey down to 35km. It is thought that when subduction stopped about 590Ma, buoyancy caused the slab to be exhumed rapidly (around 570Ma) along the pre-existing subduction faults. We were relieved to find fragments of rock with fresh surfaces in the vicinity which displayed the blue colouration well. We then moved to our second site of the day – Llanddwyn Island. The island has been interpreted as a complete Pillows in blueschist, Marquess of microplate with subduction-related facies at one end and Anglesey's Column ocean ridge pillows at the other. Faulting and folding has Photo by Tony Loftus reduced the original length of 8km to 300m. Walking to the southern edge of the island, evidence of explosive volcanism at the mid-ocean ridge was demonstrated by volcanic breccia in a matrix of tuff. Nearby, dropstones in a metamorphosed muddy matrix dated at 550-560 Ma attest to an icehouse environment. However viewing required ropes so we moved on! After lunch, pillows veined with calcite and with jasper, epidote and rhodacrosite were spectacularly displayed on the beach. Nearby was an example of the famous mélange. The mélange includes quartzite, schist and algal limestones and - in this location - is cut by a dolerite dyke of Caledonian age. Metamorphosed pillow lavas On the return, less altered pillows Mélange, Llanddwyn Island Photo by Tony Loftus with jasper, Llanddwyn Island were plentiful and showed chilled Photo by Tony Loftus margins. On the way back to the car park, a diversion through Newborough forest allowed us to examine “albite- ised” (basaltic) pillows. These had been subjected to greenschist facies metamorphism in a sodium-rich (marine) environment as a result of which Ca plagioclase has been changed to the sodium feldspar albite. Finally, spectacular bedded cherts Pillows showing chilled Bedded Chert, New-borough margins, Llanddwyn Island from sea bed sediments were a fitting Forest Photo by Tony Loftus Photo by Tony Loftus finish to a most colourful day.

Tony Loftus

Wessex Footnotes December 2015 Page 4 24 SEPTEMBER 2015 (DAY 2): BAY AND BAY Gadlys Quarry The morning was spent in the north of the island around Llanbadrig Bay and Cemaes Bay. From the car park at SH377938 we walked over the headland to Gadlys Quarry. This is a Local Geological Site, internationally important and currently awaiting SSSI status. We were again lucky with the weather, conditions being sunny and dry, albeit rather windy. We were able to see the base of a stromatolitic reef in the Precambrian limestone dating back to 860 Ma. These are the oldest recorded fossils in England and . The mélange seen here is part of the Gwna Group, the oldest rocks in the Mona Complex. Four or five reefs were visible here with more broken material making up the fore–reef. Two types of stromatolites were present. We saw the more linear, branching Gadlys Quarry Photo by Kelvin Huff form. The reef grows and is then submerged by mud through which it re-grows upwards. The organisms lived in shallow, inter-tidal conditions, like those found in the Dead Sea and Australia today. The second type of stromatolite is the onchoidal form, which Margaret likened to rows of little cabbages! Both types are formed using limestone precipitated from sea-water and were instrumental in producing oxygen for the early atmosphere. The sediments which make up the mélange here have not been metamorphosed, unlike those at Llanddwyn Island. It was suggested that this is because of the Section through stromatolitic limestone, presence of graphite on the thrust surfaces, which Gadlys Quarry Photo by Kelvin Huff was seen as small black patches on the quarry face. This acted as a lubricant. The limestone exposed in the mélange along this stretch of coast is part of a series of huge boulders up to 0.5kms across. Now that is a large clast! Technically, they are known as mega-clasts or olistoliths. The limestone was quarried in the past for quicklime or agricultural use. A lime kiln was visible above Llanbadrig Bay which used coal imported via Cemaes Bay. Cemaes Bay We descended to the beach to look at Location 2. This unique site shows evidence of palaeokarstic features seen in the form of Miocene solution pipes. There are about 12 such pipes in this area which rotted into the limestone under sub-tropical conditions during the Palaeogene era. A Miocene flora comprising 62 plant taxa has been identified from these pipes. It is possible that the entire (largely flat) surface of Anglesey was formed in this way. However, such deep surface rotting may also be associated with hydrothermal alteration from below during the Ordovician period. Both processes probably operated here. In any case it is likely that Anglesey was a land- mass by the end of the Triassic. The subsequent Quaternary glaciation then removed most of the rotted Stromatolitic limestone, near Gadlys Quarry Palaeogene material. We walked on, observing more Photo by Kelvin Huff reef-building stromatolites while following the coastal path towards Porth Padrig. The base of the limestone over a muddy mélange matrix was seen. This limestone had undergone some dolomitisation. Further solution hollows were observed, with one pipe decapitated by Quaternary glacial action.

Wessex Footnotes December 2015 Page 5 Porth Padrig At Location 3 there was a splendid view into Porth Padrig, a bay cut into the mélange deposits. At the head of the bay was the prominent White Lady, a stack formed of Precambrian quartzite. On the eastern side of the bay were rotted deposits, the result of hydrothermal alteration in Ordovician times. Ordovician deposits covered the Precambrian on the next headland. From here the mélange continues westwards to Wylfa Head, consisting largely of huge limestone boulders.

Llanbadrig White Lady stack, Porth The hamlet of Llanbadrig is named for its association with St. Patrick, Badrig Photo by Kelvin Huff who founded the church here in 440 CE. We were lucky enough to see inside the church as Margaret had made a foray into Cemaes to get the key!! In the church was a monument made of picrite (a rock of the upper mantle), which is exposed in central Anglesey. Local legend states that Patrick was shipwrecked on the small nearby island of Ynys Badrig (Patrick's Isle, also known as Middle Mouse), which we saw from the stile in the churchyard wall. From here there was a good view of the unconformity between the Pre-Cambrian mélange (860Ma) and the overlying limestones and sandstones of Ordovician age (450 Ma). As we left this serene spot we reflected upon the words of the Dalai Lama, who called it ‘the View of unconformity from most peaceful place in the world’. Llanbadrig Church Photo by Kelvin Huff Llanbadrig Headland Walking a short way westwards from the church, we also viewed St. Patrick’s Well and Cave. In this locality the first onchoids were found in the limestone. A nearby limekiln was testimony to the extraction and use of limestone in the past. Further outcrops of the mélange were examined on Llanbadrig Headland, its sedimentary nature suggesting that it only descended into the ocean trench to relatively shallow depths. The mélange matrix is muddy, sheared and schistose. Clasts are mainly limestone and quartzite on the western side. On the eastern side there was, however, some alteration of the limestone to ironstone (siderite) in places. Here, the calcium molecules had been replaced by those of iron. Beyond an outcrop of quartzite were indentations in the cliff representing Siderite deposit, Llanbadrig mined-out jasper deposits. The odd pillow lava seen suggests Photo by Kelvin Huff that this area was quite close to the mid-oceanic ridge or a seamount in the past. Cemaes After lunch we drove into Cemaes and made our way to the sea front at SH3793. Here are two of the splendid Geo Trails (No. 1, The Rock Trail), provided by the Anglesey Geopark (GeoMôn). Numbered plinths, complete with rock samples, showcase the rocks of Anglesey in chronological order, ranging from pre-Cambrian to recent (15,000 Ma). We then walked out towards the jetty following the Dyke Trail (No. 9), viewing the matrix-rich mélange with more curved structures indicating stromatolites in the Precambrian limestone. These older rocks were cut by at least four dykes of Palaeozoic age, composed of dolerite. They were probably intruded as the Iapetus Ocean closed about 450 Ma. They were typically seen as negative relief features, having been differentially weathered and eroded by marine action. This is in contrast to the more resistant baked margin of the Rock Trail, Cemaes Bay limestone, which stands out in narrow ridges. Photo by Kelvin Huff Kelvin Huff

Wessex Footnotes December 2015 Page 6 Camaes (continued) Below the first view point were some of the dolerite dykes which had intruded into the limestone that appeared as ‘walls’. Heat from the dykes baked the limestone margins resulting in low-grade metamorphism, the minerals of which resisted erosion Remains of some dykes were visible. As we walked along the cliff face we noted the abundance of stromatolites, at 860Ma some of the oldest fossils in Britain. These appeared to differ from those seen in the morning, having curved layering rather than a linear form. They varied in size from a few centimetres to about a metre in diameter. Adjacent to Section of cliff ~ 2m x 2.5m Photo by Lyn Relph these was a fine crystalline dyke Part of the dyke swarm with numerous joints. Observed slickensides indicated further crustal Photo by Gwenda Brewer movement after the dyke’s emplacement. Our next site, South Stack on Holy Island, is at the base of the Mona Complex known as the South Stack Group, Cambrian in age ~ 510 Ma. Radiometric U-Pb dating of detrital zircon in the Mona Complex indicates this group to be the youngest group in the Mona Complex, ascending to the New Harbour Group on to the Gwna Group the oldest. Recent researchers have interpreted this as a tectonic sequence referred to as Ocean Plate Stratigraphy (OPS). Accumulated sediments on the ocean floor were accreted on the underside of the opposing plate. Over millions of years further accumulated ocean floor sediments were accreted under those already present and therefore are younger, all gradually forming Horizontal folds an accretionary prism. This is contrary to a sedimentary sequence Photo by Gwenda Brewer with the youngest group on top. Viewed from the top of the cliff an anticline was clearly seen at the base of South Stack Island. On the south cliff under the lighthouse an eroded section of an anticline limb exposed a tight syncline. Rock layers at right angles had corrugated minor folds in the muddy rock layers. This alignment relates to compressional forces during the Caledonian Orogeny. Descending 400 steps to the lighthouse, the magnificent folded and faulted cliff face of the South Stack Formation was viewed from a gap (“window”) on the left-hand side of the steps. Axial planar cleavage was noted in the folds of the brittle strata. At the bottom of the steps plastic deformation was very evident in the mudstone. Strata thickness relates to original deposition, rate of subduction and compressional forces. The latter two altering as the subducting plate started slowing down during its descent into the trench. The exact timing of the folding and faulting is problematic as the region Victoria’s “window” (anec- Parasitic/laminated con- was subject to different phases of dotally, Queen Victoria sat here) voluted folds (pencil for scale) Photo by Gwenda Brewer tectonic activity. Photo by Lyn Relph

Wessex Footnotes December 2015 Page 7 The metasediments of sandy (psammites) and schistose mudstone (pelites) represent a marine turbidite. Original deposition was in shallow sea on a continental shelf. The mixing of the sediments suggest they descended at a shallow angle in which other clasts were entrained. Looking up from the bottom of the steps the main cliff face displayed some prominent strata indicating greater resistance to erosion. Brown colouration indicated the metasandstone. Quartz white veining formed when silica under high pressure was remobilised filling tension gashes. Subsequently these were folded during compression. Some of the folds in the cliff face were dislocated from further faulting. A Tertiary (~65Ma) dyke parallel to the main cliff face is known to have a ‘dog-leg’ with a left lateral displacement for about 100m at the base of the lighthouse. Originally the dyke possibly followed a linear original fault line or weakness; Remobilised quartz in main subsequent movement caused its cliff face Photo by Gwenda Brewer displacement We had enjoyed a beautiful setting with almost ideal weather conditions - except for the wind, which meant the bridge to the lighthouse was closed. We thanked Margaret and Stewart for their patience and A resident feeding chough checked our departure enthusiasm, and for giving us much to think about regarding the latest from the RSPB Reserve! theories. Photo by Gwenda Brewer Gwenda Brewer and Lyn Relph

25 SEPTEMBER 2015 (DAY 3): PARYS MOUNTAIN Parys Mountain is located about 4km south of on the island of Anglesey. It is part of the Geomôn Geopark designated by UNESCO as being of outstanding global importance, a geological world heritage site! The site has been important for 4,000 years when Bronze Age miners worked the area. However its geological history goes back to 440-480 million years ago during the Ordovician and Silurian when black smokers developed on the floor of the Iapetus Ocean. Some Ordovician trilobites and Silurian graptolites have been found in the area. The black smokers brought high-temperature fluids to the surface of the sea floor, depositing sulphides of iron, copper and lead in the form of pyrite, chalcopyrite and galena. Earth movements associated with the Caledonian Orogeny at the end Parys Mountain Photo by Alan Holiday of the Silurian caused the sea floor deposits to be folded and overturned (to the SE as the maximum pressure came from the NW) with a typical NE/SW strike characteristic of folds associated with the Caledonian Orogeny. It is likely that the tectonics caused some mobilisation of the ores with some metasomatism causing a concentration of the metals in the ore body which made them more economic. So important was the site that one mineral was named anglesite (lead sulphide). [See the photo on page 10. Ed.] Such deposits are still forming now in the major oceans of the world and will form mineral deposits for future generations (who knows?). In the 18th century Parys Mountain was one of the world’s largest copper mines but today it is important for its geology, archaeology, mining history and biodiversity. Weathering of the sulphide ores over millions of years has left a diversity of colours on the waste tips and this has also produced very acidic soils, which only a limited flora can colonise (heather, gorse and grasses), and there are still extensive areas where no vegetation can be seen.

Wessex Footnotes December 2015 Page 8 Mining took place from the Bronze Age onwards with further mining in Roman times and again in the 15th century (by Robert Parys, hence Parys Mountain). Alum manufacture occurred in the 16th century; and in the early 18th century fluids from the mine were used as medicine! Cornish miners came to the area around 1768 and much greater activity occurred in the 1770s. Thomas Williams dominated the mining activity at this time, a self-made man rather than one from the landed gentry and one who was also philanthropic. He died in 1802 and production declined. The finding of the ores and their extraction created a huge industry in the late 18th century and had a major impact on the nearby port of Amlwch which for around a decade provided the world with the Parys Mountain, view across settling pond to copper it needed. Amlwch also benefitted from river recent shaft run-off from the mine area as the waters contain ions Photo by Alan Holiday which helped to remove barnacles from ships hulls! In the 20th century further exploration occurred but with limited success. An ore body was found at depth but is not currently economic and the current downturn in commodity prices is unlikely to improve the prospects. Any new exploration is likely to be for lead and zinc ores rather than copper. Many rare minerals have been found at Parys Mountain as only a slight variation in composition creates a new mineral! Alan Holiday

ROCK OF AGES, BURRINGTON COOMBE - a note by Tony Cross (OU tutor)

I was interested in the report of the Mendips trip in the July 1930’s p 2015 edition of Footnotes and thought the following may be of interest for those interested in the history of geology. The attached image is from a postcard acquired by my parents on a ostcard trip there in the 1930s, while the memorial stone is located on

10 West Street, Farnham, Surrey. (original photographer Rock of Ages is a popular Christian hymn by Reverend Augustus Montague Toplady (1740 -1778), written in 1763 and first published in The Gospel Magazine in 1775. Traditionally, it is supposed that Rev. Toplady drew his inspiration from an incident in the gorge of Burrington Combe. It is said that Toplady, a preacher in the nearby village of

Blagdon, was travelling along the gorge when he was caught in a u storm. Finding shelter in a gap in the rocks, he was struck by nknown) the title and scribbled down the initial lyrics on a playing card.

The fissure that is believed to have provided shelter is marked as the ‘Rock of Ages’, both on the rock itself and on some maps, and is also reflected in the name of a nearby tea shop. It seems the family had no connections with Farnham, but his parents were travelling to Portsmouth when his mother went into Photoby Tony Cross labour. Toplady's father was a major in the army and was on his way to join a ship for South America. The original cottage is long gone; 10 West Street has since been rebuilt and is part of a shop which carries the memorial tablet. Rather fittingly, the fossiliferous stone was sourced from

Burrington Combe. There is also a brass inscription to Toplady in the south chapel of St Andrew's Church, Farnham. Tony Cross

Wessex Footnotes December 2015 Page 9 SIMPLE GUIDE TO MINERALS 17 - by Colin Morley

MUSCOVITE KAl2(AlSi3O10)(OH)2 Sometimes known by descriptive names such as Muscovy Glass, Cat Silver and Lapis Specularis (stone mirror). The sources from Russia cleaved into large sheets that were used for a variety of purposes including as a fireproof window in the doors of stoves, heaters and furnaces (hence the names Muscovy Glass and muscovite). Muscovite has many other useful properties including being dielectric (not conducting electricity). It is also very useful as a filler in insulation boards. It is the most common member of the Mica Group. It's commonly found in crystalline masses called 'books' because it is made up of monoclinic thin 'flaky' sheets. With a hardness of 2.5, it is a basic potassium aluminum silicate, sometimes with some chromium or manganese replacing the aluminum, so the formula can vary. It can be easily distinguished from biotite, another type of mica, because muscovite is light and pearly, while biotite is very dark in colour. There should be no need to streak test this mineral, but if you do, it streaks white. It is found in both metamorphic and igneous rocks as well as hydrothermal intrusions. It is found in granitic and andesitic rocks but it depends on the presence of water in the magma. The foliation in gneiss is made more obvious with the presence of shiny, platy, mica crystals. Specimen in the Morley Collection Photo by Colin Morley This specimen was found in a hydrothermal vein deposit in Arizona. The large outcrop ran for several miles on the surface and also had a large amount of quartz; this had attracted prospectors looking for the presence of precious metals. You may be able to see the signs of some trace copper in this specimen. [See the colour photo at http://ougs.org/wessex Ed.] Although muscovite can be found all over the world, Brazil, China, India are the largest producers. It is also common in Arizona. Colin Morley

OUGS AGM & SOCIAL WEEKEND 15 – 17 APRIL 2016 SCARBOROUGH The AGM is at 2pm on Saturday, 16 April 2016 at the Red Lea Hotel in Scarborough. There will also be lectures, the annual dinner and entertainment plus local field trips on the Sunday to see dinosaur footprints and Whitby Mudstone. Details, including the AGM notice and a booking Anglesite, Parys Mountain Mines form, are in the November 2015 edition of the Anglesite-190547" by Rob Lavinsky, iRocks.com – CC-BY-SA-3.0. OUGS Newsletter and on the website Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://ougs.org https://commons.wikimedia.org/wiki/File:Anglesite- 190547.jpg#/media/File:Anglesite-190547.jpg

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 other members? All Residential Trips Mark Barrett [email protected] contributions welcome. Website Manager Colin Morley [email protected] Librarian Jeremy Cranmer [email protected] Hilary Barton, Editor [email protected] Ordinary members: Ian Hacker, Tony Loftus, Linda Morley, Marion Phillips, Jane Mead

Wessex Footnotes December 2015 Page 10

How The West Was Made Open University Geological Society Symposium 2016 Friday 8th to Sunday 10th July 2016 Exeter University – Streatham Campus The Spade marks the spot

Exeter Symposium will be jointly hosted by South West, Wessex and Severnside branches. We would like to invite you to join us for a splendid weekend of lectures, field-trips and social events in the heart of the South West. Accommodation in Holland Hall is en-suite with double beds; rooms can be booked before and after the Symposium weekend so you can extend your stay. Lectures will be held in Peter Chalk Hall which is within easy walking distance of the accommodation

Lecture Programme  Prof Iain Stewart (Plymouth University) Introductory lecture on Friday evening.  Dr Richard Scrivener (ex BGS) Red rocks and volcanoes - the Permian of .  Dr Robin Shail (Exeter Cornwall Campus (CSM) Early post-Variscan tectonics and magmatism.  Prof Peter Scott (Exeter Cornwall Campus (CSM) Industrial and Construction minerals.  Dr Robin Shail (Exeter Cornwall Campus (CSM) SW England granites and their associated mineralisation.  Prof Frances Wall (Exeter Cornwall Campus (CSM) Critical West: rare earth minerals.  Dr Mark Anderson (Plymouth University) Tectonic Inversion on the Somerset Coast.  Dr Stephan Harrison (Exeter Dept of Geography) Dartmoor Glaciation.  Dr Jenny Bennett (OU) Dating River Terraces of the Exe.  Felicity Liggins (Met Office) How the South West is shaped by weather.  Chris Yeomans (BGS) TELLUS South West South West England: a view from above.

THE FIELD TRIPS on Saturday afternoon will include a boat trip along the Jurassic coast from Exmouth (with space for all participants), disembarking on the shingle beach at Seaton and returning by coach. We will be going very close to the shore so we can see the geology. Richard Scrivener and Robin Shail will use the ship’s tannoy to point out and explain the geological features. There are contingency plans for inclement weather and alternative trips to Dartmoor and Exeter cathedral. THE FIELD TRIPS on Monday include a guided tour of The Met office in Exeter, a further tour of the City Centre and a possible visit to a mine. Thinking of extending your stay either side of the Symposium weekend? We have arranged additional field trips to Torbay Geopark and the Jurassic coast of / in the week before and the 2-3 days after the Symposium weekend respectively. For more details see http://ougs.org/society_events/ Or contact Sheila on [email protected] for a booking form

Wessex Footnotes December 2015 Page 11 OTHER LOCAL EVENTS – PLEASE CONTACT THE ORGANISERS DIRECT

Dorset Natural History & Archaeological Society LULWORTH RANGE WALKS GEOLOGY LECTURES AT DORSET COUNTY MUSEUM High West Street, Dorchester DT1 1XA & VILLAGE For information on opening times 9 Dec 2015 Ignite! (Christmas party, geology talks etc) tel. 01929 404819 13 Jan 2016 Mapping the Great Undercliff Landslides (Richard Edmonds) 10 Feb 2016 Diamonds Through Time (Prof. Andy Fleet) OPEN EVERY DAY OVER HOLIDAYS 9 Mar 2016 Taphonomy (Dr Peter Andrews & Dr Sylvia Hixson) 19 December 2015 – 3 January 2016 All welcome. Lectures start at 7pm. 24 March – 3 April 2016 Donation of £3 suggested to cover speakers’ expenses. 30 April – 2 May 2016 Further information: tel. 01305 262735. 28 May – 5 June 2016 http://www.dorsetcountymuseum.org/events 30 July – 4 September 2016 18 December 2016 – 7 January 2017 OPEN EVERY WEEKEND EXCEPT: 16-17 January 2016 DORSET GEOLOGISTS’ ASSOCIATION GROUP (DGAG) 13-14 February 2016 12-13 March 2016 www.dorsetgeologistsassociation.com 8-9 October 2016 12 Dec 2015 Christmas workshop, Broadmayne 19-20 November 2016 9 Jan 2016 AGM and lecture on meteorites, Wool 10-11 December 2016 5 Mar 2016 Field trip to Eype (Geoff Townsend) OUGS members welcome but check beforehand that spaces are available. Contact: Doreen Smith tel. 01300 320811 or e-mail xxxxxxxxxxxxxxxxxxxxxxx THE OXFORD COLLOQUIUM 10am-5pm, Saturday 5 March 2016 Oxford Museum of Natural History, Oxford DIGS: Dorset’s Important Geological Sites Group £20 for the day, must pre-book More details from Alan Holiday: xxxxxxxxxxxxxxxxxxxxxx http://www.ogg.uk.com/#!the-oxford- Website at: http://www.dorsetrigs.org.uk colloquium-2016/c8qx If you would like to be kept informed of forthcoming Lectures on a wide range of topical subjects by six conservation sessions, please contact Alan, who will be happy eminent Professors: Hazel Rymer (OU), Chris to add your name to his e-mail circulation list Stringer (NHM), Paul Upchurch (UCL), Chris Ballentine (Oxford University), John Underhill (Herriot-Watt University) and Sarah Davies (Leicester University). Subjects from human evolution to volcanology, and RUSSELL SOCIETY, SOUTHERN BRANCH from hydrocarbons to the interpretation of buried http://www.russellsoc.org/ landscapes. Plus a geo-ramble the following day. Gary Morse: xxxxxxxxxxxxxxxx, tel. xxxxxxxxxxxx. For anyone interested in minerals, the Branch runs summer field trips plus winter lecture meetings on the second Thursday of the month at Wyvern Technical College, Fair Oak, Eastleigh, Hants. 10 Dec 2015 Minerals of the Cairngorms (Roy Starkey) SOUTHAMPTON MINERAL & FOSSIL SOCIETY 14 Jan 2016 AGM, plus quiz and mineral swaps http://www.sotonminfoss.org.uk 11 Feb 2016 Mineral collecting in Maine pegmatites (Rob Tripp) 10 Mar 2016 Italian Minerals (Marco Petrovich) Gary Morse: xxxxxxxxxxxxxxxx, tel. xxxxxxxxxxxx The Society runs indoor meetings, field trips and other activities relating to the collection of minerals and fossils, and the sites where they are found. Monthly evening meetings are held at The Friends' Meeting BOURNEMOUTH NATURAL SCIENCE SOCIETY House, Ordnance Road, Southampton (guests 39 Christchurch Road, Bournemouth BH1 3NS welcome). http://www.bnss.org.uk 15 Dec 2015 Recenseo Annus 2015 The Society covers all the branches of natural science, including geology and palaeontology. It has an extensive, and very impressive, collection of fossils, rocks and minerals which can be viewed, by appointment, on any Tuesday morning. DORSET BUILDINGS GROUP Forthcoming lectures include John and Sue Rowntree, xxxxxxxxxxxxxxxxxxxxxx 2 Dec 2015 Vulcanology in the Solar System The Group aims to promote the preservation of Dorset’s (Sheri Karl) building traditions and so takes a practical interest in Check the website for the Jan-Mar 2016 programme. building stones and local geology. Winter lectures held at Holt Village Hall, Dorset (entry £5, includes tea and cake). YOUNG EXPLORERS’ CLUB (geology and more!) For children aged 7 to 12. £4 per child per meeting. 10 Jan 2016 Conservation of Corfe Castle (Sally Strachey) 10am to 12.30pm on 12 Dec 2015 7 Feb 2016 Cage Chantries (Cindy Wood) http://www.bnss.org.uk/about/young-explorers 6 Mar 2016 Druce Farm (Lilian Ladle)

Wessex Footnotes December 2015 Page 12 WESSEX BRANCH EVENTS – DETAILS

WESSEX OUGS AGM AND DAY OF LECTURES: MARS, MULL & MOUNTAINS

10.15am to 4.00pm, Saturday 23rd January 2016 Please contact Sheila Alderman if you plan to attend on [email protected] Please also let Sheila know if you have a collection or display you would like to exhibit.

PROGRAMME AGM AGENDA 10.15 Registration 1. Apologies for absence 2. Minutes of last meeting 10.30 Dr Ian Williamson: The Geology of Mull 3. Matters arising 11.30 Dr Tom Argles: A Random Walk Through 4. Agenda items received the Timescales of the Himalaya 5. Officers' reports: 12.45 Buffet lunch provided by the committee and  Branch Organiser (Sheila Alderman) friends  Treasurer (Rhiannon Rogers)

13.45 AGM (agenda at right)  Day Trips & Library (Jeremy Cranmer)

14.30 Dr Susanne Schwenzer: Curiosity at Gale  Newsletter (Hilary Barton)  Website (Colin Morley) Crater, Mars Non-members welcome, but can’t vote at AGM!  Residential Trips (Mark Barrett) 6. The committee will then stand down for: DIRECTIONS 7. Election of officers D’Urberville Centre, Colliers Lane, Wool, Dorset 8. Any other business Postcode: BH20 6DL. Map ref: SY 843 865. The whole day is free of charge Five minutes’ walk from the railway station in Wool. as a “thank you” to members for Train times at: http://www.southwesttrains.co.uk/ all their support.

Near Frome, Somerset Sunday, 28 February 2016 INTRODUCTION TO THE GEOLGY OF THE MENDIPS Vallis Vale and Tedbury Camp, with Alan Holiday To book a place, contact: Jeremy Cranmer at [email protected] or tel. xxxxxxxxxxxx Alan Holiday taught geography and geology in Weymouth from 1971, most recently at Weymouth College. 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 those who are new to geology. This site is a great location to extend the knowledge gained on the Introduction to Geology field trip to on 29 November 2015. However, while it is complementary, it is not necessary to have attended the first one. We shall 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 and 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.

Cranborne Chase, near Wimborne St Giles, Dorset Sunday, 13 March 2016 DOWN FARM, WITH MARTIN GREEN To book a place, contact: Jeremy Cranmer at [email protected] or tel. xxxxxxxxxxxx The Down Farm Landscape (where Martin's family has farmed for generations) is one of the most carefully studied areas in Western Europe. Much of this work has been carried out by Martin himself - who in 1992 won the Pitt Rivers award for independent archaeology and has also been awarded an honorary doctorate of the University of Reading. The work has involved five universities and one of the major field units was featured in a BBC2 'Meet the Ancestors' programme. The farm not only contains the Neolithic Dorset Cursus, numerous long barrows and Hambledon Hill, but over the last 30 years henges, shafts, plastered houses, land divisions, enclosures and cemeteries have been identified and exacavated. The farm has its own museum and Martin has published a book “A Landscape Revealed: 10,000 Years on a Chalkland Farm”. We shall study the chalk landscape and its evidence of periglacial conditions during the last ice age. We shall see the big shaft and many of the archaeological and geomorphological features on the walk around the farm. Martin will give a demonstration of flint knapping and the museum can be visited for a small donation.

Wessex Footnotes December 2015 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 ONCE YOU’VE SIGNED UP FOR A WESSEX DAY TRIP, JEREMY WILL E-MAIL THE HAND-OUT TO YOU A FEW DAYS BEFORE THE EVENT SO THAT YOU CAN READ IT IN ADVANCE.

DATE EVENT LEADER(S) CONTACT

Saturday Wessex Branch AGM and lecture day Sheila Alderman Sheila Alderman 23 January 2016 Wool, Dorset [email protected]

Introduction to Mendips Geology Jeremy Cranmer Sunday Vallis Vale, Somerset. Alan Holiday [email protected] 28 February 2016 (suitable for those new to field geology) tel. xxxxxxxxxxxx

Jeremy Cranmer Sunday Down Farm, Dorset Martin Green [email protected] 13 March 2016 tel. xxxxxxxxxxxx

A week on the Isle of Mull Mark Barrett 14 – 21 May 2016 Ian Williamson (waiting list only) [email protected]

OUGS AGM and social weekend John Gooch 15 – 17 April 2016 OUGS Scarborough [email protected]

Saturday Jeremy Cranmer Purbeck Ball Clay June 2016 Andrew Deeming [email protected] Norden, Dorset (date tbc) tel. xxxxxxxxxxxx

OUGS Symposium, Sheila Alderman 8 – 10 July 2016 OUGS Exeter University [email protected]

Jeremy Cranmer Tuesday Beer and Seaton Hole Alan Holiday [email protected] 12 July 2015 Devon tel. xxxxxxxxxxxx

Jeremy Cranmer Wednesday Lyme Regis coastal defences Alan Holiday [email protected] 13 July 2016 Dorset tel. xxxxxxxxxxxx

Jeremy Cranmer Wednesday Moon’s Hill Quarry, Somerset Gill Odolphie [email protected] 17 August 2016 (limited to 20 members) tel. xxxxxxxxxxxx

Beginning Geology at Bowleaze Cove Jeremy Cranmer Sunday Weymouth Alan Holiday [email protected] 13 November 2016 (suitable for those new to field geology) tel. xxxxxxxxxxxx

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 2015 Page 14