SABRINA TIMES DECEMBER 2012 OPEN UNIVERSITY GEOLOGICAL SOCIETY SEVERNSIDE BRANCH

Branch Organiser’s Report

Dear Members In this issue: We ended our field season with a good day at Penarth in the middle of November. Building Stones of 2 As has become our practice this was our Introductory Day aimed at new students Newport who now start their studies in October. As usual, there was an excellent response.

Introductory Day in 4 Our next event is the Day of Lectures in the Oriel Suite of the National Museum in th Penarth Cardiff on Saturday, 8 December. We have 2 professional speakers in the morning who will talk to the theme of Polar Regions. Tom Sharpe will explain the geology of Events & National 7 Antarctica and Mark Brandon will describe the making of the TV series ‘The Frozen News Planet’. We will be going for lunch in the nearby Pen and Wig and in the afternoon a number of members will give short presentations on a geological theme. Branch Committee 8 and Editorial There will be Second Hand Book Sale on the day. The books have come from two sources. The Branch has been given many books by the widow of one of our Contacts 9 members who sadly passed away earlier this year. The other books are being sold by the South Wales Geological Association. Message from 9 Membership The library won’t be available this time but please bring back all books and maps Secretary that you have borrowed previously. I will bring it along to the AGM in February.

nd AGM Agenda 10 The Branch AGM will be held on Saturday, 2 February 2013, again in the Museum. You will find the agenda elsewhere in this Newsletter. This is as much a social Membership 11 event as a business one. The meeting only takes a short time and we have a Renewal Form speaker after lunch. The Branch library will be available for you to borrow maps and books. We have received several new items in the last couple of months so there is bound to be something to tempt you from easily read texts to more academic volumes. Please come along and join us.

Jan is making plans for the programme next year. She will be able to update us at the meeting. The first event of 2013 will be the Lab weekend in Aberystwyth in February. This time we will be looking at metamorphic minerals. Our hosts, as usual, will be Charlie and Bill. It is a popular event, drawing members from across the Society.

Best wishes

Janet

MERRY CHRISTMAS AND A HAPPY NEW YEAR TO ALL OUR READERS

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Building Stones of Newport - 21 October 2012

Janet Hiscott led ten members on a varied and enjoyable look at some of the good things of her native city. We began with the building stones of some of central Newport, based on the GA South Wales Group leaflet compiled by our old friend Eric Robinson. The first building, near where some of us had parked, was the old covered market, with walls of bolster-dressed grey-green Coal Measures sandstone passing up into similarly dressed Old Red Sandstones pitted with cavities; the cornices and window surrounds being of Bath Stone. John Newman in Buildings of Wales – Gwent calls it “the most conspicuous sign of Newport’s late Victorian civic pride,” and “composed in the manner of a Flemish cloth hall.”

In the High Street are a number of striking commercial buildings; the first we looked at, not mentioned by Robinson, was Royal Chambers, “inter-war Neoclassicism”, in Portland stone with ugly concrete canopies above shop fronts and some granite on the street corner. Opposite is Newport Arcade, by the dominant late 19th local architectural practice of Habershon, a long fifteen bay frontage of Bath Stone.

At the top of the High Street is the “towering facade” of the former Post Office in what Robinson says is Ruabon brick (seems a long way to bring it in 1905 when Malpas was so near) lavishly dressed with very fossiliferous Portland stone. Outside is a remarkable large block of stone commemorating the D-Day landings (re-located fairly recently); long cogitation made us think that it must be the red stained Carb Lime familiar from Castell Fig. 1 Detail of Covered Market. Coch.

At the bottom of the High Street two very different buildings of the same date face each other: the Principality Building Society of 1891 in red brick and terracotta and the National Westminster, originally National Provincial, Bank of 1892, which like the next building up from the red one is of Pennant gritstone with Bath dressings, but the bank also on an attractive base of silvery Cornish granite with both biotite and muscovite mica. The former Westgate Hotel too has for its basic construction Pennant stone, cut into quite small blocks as in other buildings around; it differs in that the dressings are of Beer Stone, hard chalk from southeast Devon. The door is flanked by columns of polished Shap granite, immediately recognizable from its large pink feldspar phenocrysts. Some more ordinary red granite underneath is presumably a later insertion, a piece of facing as also in another nearby building.

We toiled up Stow Hill, noticing the Pennant-and-Bath Bethel Community Church, the all-Bath RC church with its orange Ham Hill Stone presbytery (the only use in Newport of this shelly Liassic limestone from the Yeovil area ) and came to a joyous halt at the Presbyterian Church of Wales Fig. 2 Centre of Royal Chambers building in Havelock Street. This makes a striking effect by using a wide variety of stone: ORS, Carb Lime, various other limestones, some with corals and crinoids, granites, gabbros…. Bath Stone dressings, of course. Eric Robinson thinks that some of the more distant rock may have come to Newport as ballast. The church hall next door is of similar design but less variety. They come, surprisingly, from the Habershon firm of architects, the church being 1864. Further up Stow Hill is St. Woolos Primary School of 1904-5, as Newman says “built on a grand scale and sited toweringly on the slope…three storeys, a rarity in Wales.” Rock-faced Pennant below, red brick and Portland above. How much have children of Newport appreciated (for it is still in use) the “lavish Baroque details… three big aedicules… open segmental pediments carried on blocked Ionic pilasters”? Mr. Gove would disapprove of such lavishness for any modern school…

Fig. 3 Presbyterian Church of Wales, Havelock Street 2

Building Stones of Newport - 21 October 2012 (contd.)

At the top of the hill is St. Woolos cathedral, on the site of the saint’s bedd eglwys of about 600 AD, now represented by the curious extended narthex through which one enters the perfect Norman nave. There is much purplish ORS; the local St. Maughan’s group, according to Robinson. A great many other stones have been used in various rebuildings and extensions. We met the comparatively new Dean, who dislikes the striking Piper/Reintiens reredos and east window in the early 1960s chancel, and the pews which prevent one admiring the nave arcades sufficiently. It is to be hoped that whatever else he does, and some clergy love to make their mark architecturally, he will not as he would like create a chapel in the narthex. Although it is called “St. Mary’s chapel” it would make a most curious entrance to the building.

For lunch we moved downstream to one of Newport’s prides, the Transporter Bridge of 1901-6, and ate our sandwiches while admiring this curious and impressive structure, and resting from geological considerations. Fig. 4 Exposure of Lias at Goldcliff

Janet then took us across the Gwent Levels to Goldcliff, an inlier of Lias on the coast (Fig. 4). We looked at the small exposure, and at the Triassic foreshore which was being exposed by the falling tide, but not fast enough for us to venture down (Fig. 5). Janet had been down on it with Tom Sharpe, and had to report, regretfully, that possible dinosaur footprints (as we have seen with him at Barry) were probably dewatering structures.

Thank you, Janet, for an excellently varied day; and Linda for extra notes on the building stones.

Fig. 5 The tide recedes at Goldcliff – not fast enough! Report by Philip Clark

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Introductory Day in Penarth - 18 November 2012

Leader: Dr. Christian Baars, Department of Geology, National Museum of Wales

A large group of members, including some on their first outing with Severnside, met at Penarth Pier and explored the Site of Special Scientific Interest (SSSI) between there and Lavernock Point to the south. (Fig. 1)

The following description of the geology in the area is reprinted from the comprehensive handout presented by Dr. Baars:

At the base of the sequence, several metres of red lime-rich mudstones (marls) of the Branscombe Mudstone Formation of the Mercia Mudstone Group (formerly Keuper/Red Marls) are exposed, initially Fig. 1 Severnside on Penarth beach dipping south at a shallow angle. These formed in a continental fluvial environment, probably as aeolian sediment in the vicinity of a large lake under a generally arid climate. Triassic rocks are considerably thicker within the Bristol Channel Basin than further north, indicating that deposition was controlled by syndepositional fault movement. The overlying Blue Anchor Formation consists of Fig. 2 Blue Anchor Formation overlying thin alternating beds of mudstone, siltstone and red mudstones limestone.(Fig. 2) These were deposited in shallow water under initially reducing (yellow/green) and later oxidising (grey). The lower part contains gypsum (white and pink alabaster) nodules, (Figs.3 and 4)and in the middle part three distinctive beds of red mudstone form a useful marker horizon (the Pink Band).

The lowest beds of the Penarth Group are marked by the Westbury Formation (Fig. 6), which are dark grey to black; the contact between the Blue Anchor Formation and the overlying Westbury Formation is disconformable (an unconformity is an erosional break that is represented elsewhere by rocks). Thick beds of black shale alternate with thinner sandstones and limestones in six cycles; each cycle begins with a hard sandstone or impure limestone and continues with dark shales and bivalve-rich horizons.

Thin layers of fibrous calcite, formed post-depositional, are called 'beef’ as they are thought to resemble cut steak. Pyrite is common on the surface of some of the sandstones. The low Fig. 3 Gypsum nodules in diversity fossil fauna includes mainly bivalves (Chlamys valoniensis, Eotrapezium, Liostrea, Blue Anchor Formation Placunopsis, Pleuromea, Rhaetavicula contorta) ; thin biscuit-coloured beds often have abundant Protocardia. The small gastropod Natica also occurs. Several bone beds occur in the Westbury Formation, which contain fossil bones (including bone fragments and vertebrae of marine reptiles, such as ichthyosaurs and plesiosaurs), fish teeth and scales, and coprolites. These beds were deposited in a very shallow marine setting, each in a single storm event, marking the early part of the Rhaetian marine transgression over an extensive area of low relief. The Lilstock Formation (Fig. 6) consists of light grey sandstones, limestones and mudstones. its lowest beds (Cotham Member) are of grey mudstones overlain by a series of thin sandstones, often stained rusty brown, forming a prominent feature in the cliff face. Ripple marks, often with infilled mud cracks, occur on the surfaces of many of the sandstone beds (Fig 5); at Lavernock Point some of Fig. 4 Gypsum nodule the mud cracks are up to 50cm deep. The Cotham Member records a significant regression, resulting in lagoonal conditions and regional emergence.

Fig. 5 Ripples and mud cracks The upper beds, the Langport Member (Fig. 6) are mudstones and limestones or calcareous shales which weather to a cream colour. The Langport Member marks a return to restricted marine conditions. Some of the thin limestones contain a fauna of shallow marine sessile bivalves, such as abundant shells of Liostrea, Modiolusus and Dimyopsis and, in the uppermost beds, spines of sea urchins. Deposition was in a shallow marine lagoon environment.

Contd.

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Introductory Day in Penarth - 18 November 2012 (contd.)

Westwards of Lavernock Point, the Blue Lias Formation is exposed which is subdivided based on the ratio of limestone to shale. The Blue Lias was deposited under fully marine conditions. Much of Europe lay beneath a generally shallow sea throughout the Jurassic; accordingly, depositional conditions are fairly uniform over a large geographical area. The succession records a progressive sea level rise, accompanied by a change in climatic conditions. Liassic rocks along the coast of the Vale of Glamorgan are adjacent to Palaeozoic rocks and evidence of small islands over parts of south Wales, with marginal Triassic sequences recorded at Sully Island and Barry Island.

The lowest beds of the Blue Lias Formation (thin tabular limestones with subordinate mudstones) belong to the Bull Cliff Member and are Triassic in age. They contain Liostrea but no ammonites; the fauna indicates slow sedimentation and a firm substrate.

The start of the Jurassic is marked by the first ammonite-bearing, more shaley beds above the Bull Cliff Member in the succeeding St Mary's Well Bay Member (approximately 50% shale : 50% limestone) which contain large numbers of flat ammonites, possibly Psiloceras planorbis and, a little later, P. johnstoni (Planorbis Zone). Fossils are abundant in slightly higher beds, for example the ammonite Caloceras johnstoni, the bivalves Plagiostoma gigantea and Gryphaea, and star- shaped segments the crinoids. Sedimentation rates were increased compared to the Bull Cliff Member, with gentle currents and well-oxygenated bottom conditions. This is overlain, marked by a change of slope, the Lavernock Shales Member Fig. 6 Westbury Formation (bottom), (Liasicus Zone; 75% shale : 25% limestone), the type section of which is between Lilstock Formation and Langport Lavernock Point and St Mary's Well Bay. This comprises blue-grey, calcareous Member (top) mudstone with burrows and subordinate thin beds of nodular limestone, marking a rise in sea level. Fossils include crinoid and echinoid fragments, ostracods, bivalves and ammonites.

At the top of the Blue Lias Formation, the cliff face of the Porthkerry Member (Angulata, Bucklandi and Semicostatum Zones) is steeper again. As in the Lavernock Shales Member, limestones alternate with mudstones but their ratio is reversed (25% shale : 75% limestone), recording an extended period of offshore shelf sedimentation. Further west along the coast, the Porthkerry Member forms the main component of spectacular sea cliffs. Fossils include bivalves (including Pinna and Plagiostoma), echinoids, ammonites and gastropods; corals such as Montlivaltia are abundant on the bedding planes of some limestone beds; the bivalve Gryphaea is common in the shales, and the large branching burrowing systems of the trace fossil Thalassinoides are widespread. The limestone beds increase in abundance and thickness into the Bucklandi Zone. Deposition was in a shallow sea under generally aerobic conditions although the presence of bituminous shales in places indicates a lack of oxygen at times.

Contd.

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Introductory Day in Penarth - 18 November 2012 (contd.)

Carboniferous Limestone The sub-Triassic rocks around Cardiff and Barry are Carboniferous Limestone, best seen at Sully Island and Barry Island. At both islands boulders of Carboniferous Limestone can be seen within the Triassic conglomerate, where the Mercia Mud- stone Group was deposited on top of or adjacent to hard, grey limestones of the Black Rock Limestone Group, marking an unconformity of approximately 140 million years.

Radyr Stone A Triassic rock which has been used extensively in the building of Penarth Docks, and which is very different from the rocks of the Mercia Mudstone Group, is the reddish Radyr Stone. This is composed of mainly coarse, fairly angular, grey pebbles of Carboniferous Limestone set in a red sandy matrix (breccia). it represents the marginal facies of the Mercia Mudstone Group and was quarried north of Cardiff (near Radyr and St Fagan’s).

Faults and Folds The Mesozoic rocks are folded into shallow synclines and anticlines for example the Syncline, best seen looking west from Lavernock Point. Another syncline oc- curs at Penarth Head, although this is disturbed by considerable faulting; the Penarth Fault extends for several miles in a north-westerly direction at least as far as Ely, west of Cardiff. The Lavernock Fault brings red and yellow Triassic mud- stones and sandstones alongside the rocks of the Blue Anchor and Westbury for- mations; the vertical movement involved is approximately 160m. Along the entire section many other smaller faults can be seen, including graben structures (Fig. 7), associated with the breakup of Pangaea.

Fig. 7 Severnside admiring a graben Photographs by the Editor

The day ended with a brief demonstration to new members of the principles of measuring strike and dip using a compass and clinometer before walking back along the cliff top to Penarth.

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Severnside Branch Events

DATE EVENT LEADER DETAILS

2012 Meet at 10am Tea and coffee will be served. Day of Lectures Lecture 1 - Tom Sharpe Geology of Antarctica. December 8th Museum of Wales Lecture 2 Mark Brandon, OU Milton Keynes. The making of "The Cardiff Frozen Planet" Lunch at the Pen & Wig then presentations by members

2013

Branch AGM To be held in Museum of Wales, Cardiff February 2nd & Talk Aberystwyth February Charlie Bendall & Metamorphics Friday to Sunday in the labs at Aberystwyth University 22nd - 24th Bill Perkins Accommodation at the Park Lodge Hotel

National News and Events

The Symposium will be held in Dublin 9 - 11th August 2013

A full list of all forthcoming Society events can be found on the OUGS website http://ougs.org/index.php Look at the useful websites on the Main home page of the national site. There are some very interesting links there.

There are two vacancies on the National Committee: National Newsletter Editor No particular skills required just an interest in helping to communicate with all our members. Events Officer Again no particular skills required, the job is very much what someone wants to make of it. Far less onerous than it was now that all events are entered onto the website. If you don't want to do them yourself, can you persuade someone else who may be interested? Neither of these jobs need any knowledge of software packages or previous experience.

The Moyra Eldridge Photo competition takes place at the AGM (April 2013) - it is really great to see all the excellent photos that our members take - there are some very talented people out there. Our ex-treasurer is one - has anyone noticed her photos appearing on the front page of the OUGS Newsletters?

There will be an Open Day in Walton Hall for Earth Science probably early in July 2013. This will not be a public affair but just for current and past students with departmental visits and lectures. There may be field trips on the Sunday. More details to follow. Keep an eye on the national Newsletter and the events page of the website.

A message from the Geological Society (Southern Wales Group)

Join us on Saturday 23 February 2013 as the Southern Wales Regional Group celebrates its 21st birthday. We’re taking over the National Museum in Cardiff to host ‘Geology Rocks!’ a one-off celebration of geology.

Visit the main hall for displays and demonstrations - want to know how to make a volcano? Want to learn more about the chocolate rock cycle? We’ll be revealing all on the day. We’ll also be running behind the scenes tours of the geology department and guided tours of the ‘Evolution of Wales’ exhibition. And to top it all we have Professor Iain Stewart (presenter of Volcano Live, How to grow a planet, Men of Rock & How Earth Made Us) giving a special guest lecture.

Free entry for all the family, so please come along and join the party. 7

Event Notes Note: EVENT DETAILS CAN CHANGE Any last-minute changes of times or arrangements are on the OUGS website.... www.ougs.org Or...... Contact Jan Ashton-Jones Tel: 01432 870827 Email: [email protected] If you are not receiving email reminders from Janet regarding forthcoming events or if you get a new email address please let her know so that she can keep in touch.

Transport If you are able to offer a lift to any event or if you have local knowledge regarding bus or train services etc. that might help those without their own transport to attend an event please let Janet know. Updates Why not try the following link to a service for keeping an eye on changes in the events list. http://www.changedetection.com

THERE IS A NOMINAL FEE OF £2 ON DAY TRIPS (UNLESS OTHERWISE STATED) TO COVER LEADERS EXPENSES. ALWAYS WEAR APPROPRIATE GEAR...WARM CLOTHING AND HIKING BOOTS. BEAR IN MIND THAT MANY SITES, ESPECIALLY QUARRIES, REQUIRE THE WEARING OF HARD HATS. ACTIVE QUARRIES REQUIRE HARD HATS AND YELLOW JACKETS.

IMPORTANT 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 and Personal Liability cover remain the responsibility and personal choice of the participant. There may be an element of appropriate cover included in house or travel insurance. Although OUGS activities are not particularly dangerous members are advised to check whether exclusions apply to activities in which they propose to participate in case they wish to arrange further cover. An annual travel insurance may be the best solution for any member who regularly attends field events. This is again a matter of personal choice. All members participating in overseas events will be required to have travel insurance for the duration of the event. Participants should be covered for Medical, Repatriation and Personal Liability expenses. The Personal Accident element remains the personal choice of the member. Disclaimer None of the information in any of the advertisements for field trips or other events in this newsletter constitutes a brochure under the Package and Travel Regulations (1992) OUGS Severnside Branch Committee Janet Hiscott - Branch Organiser 01633 781557 (evenings) [email protected] Averil Leaver - Treasurer 01446 418592 [email protected] Jan Ashton-Jones - Events 01432 870827 [email protected] Jan Boddy 01793 762575 [email protected] Kath Addison-Scott 01179 538085 [email protected] Anthony Bukowski 02920 300080 [email protected] Philip Clark 01885 483697 [email protected] Elizabeth Edmundson 01792 863119 [email protected] John de Caux - Newsletter 01633 875955 [email protected] OUGS Sales Is your fieldwork kit lacking a few items? If it is check out OUGS sales! They can supply all you require...... Hand lenses, Lanyards, Notebooks, Reference Cards and much more! Click on ‘sales’ on the OUGS website www.ougs.org Library The Branch Book and Map Library list is online The library is in the care of Branch Organiser Janet Hiscott Request a catalogue from...... [email protected] Editorial To receive the colour version of this newsletter by email in .pdf format just send a request to [email protected] Why not share your geological experiences with other members? All contributions for the newsletter will be very welcome. We can read or scan most data formats or documents. For photos please send the images as separate files, preferably in jpeg (.jpg) or bitmap (.bmp) format. Contributors should note that reports, photographs and other contributions may also be reproduced in the OUGS newsletter. Finally…. A big vote of thanks to Jan and Janet for a great program of events in 2012. 8

OUGS Neighbours It’s worthwhile taking a look at what other branches are doing. Many of their events could be convenient to attend.

OUGS Oxford Branch Organiser: Sally Munnings 01635 821290 [email protected]

OUGS Southwest Branch Organiser: Chris Popham 07971 930431 [email protected]

OUGS Wessex Branch Organiser: Sheila Alderman 01935 825379 (eve) [email protected]

OUGS West Midlands Branch Organiser: Linda Tonkin 01902 846074 [email protected]

Other Organisations Many of our members belong to other Earth Science related organizations which also do interesting events.

Welsh Stone Forum http://www.museumwales.ac.uk/en/364/.

Geologists Association Secretary: Sarah Stafford 020 7287 0280 [email protected] Affiliated Regions: South Wales www.swga.org.uk West of England www.wega.org.uk Bath Geology Society www.bathgeolsoc.org.uk

Avon RIGS Group The Avon RIGS Group are re-launching their newsletter, Outcrop, as an on-line blog. The relevant websites are: www.avonrigs.org.uk http://avonrigsoutcrop.blogspot.com

The Russell Society www.russellsoc.org.uk

Message from the Membership Secretary

RENEWAL REMINDER TO MEMBERS FOR 2013

If you are a continuing member renewals should be made on 1st January each year.

Please note the following: 1. If you joined after 1st July 2011 your subscription is due 1st January 2013. 2. If you were late in renewing for 2012, as I have received some late subscriptions even in September, remember that you still have to renew again 1st January 2013. 3. If you joined after 1st July 2012 you do not have to renew until 1st January 2014. 4. Use the attached renewal form (Page 11)

Thank you Phyllis Turkington OUGS Membership Secretary

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Open University Geological Society AGM of the Severnside Branch

Oriel Suite, National Museum of Wales, Cardiff

2nd February 2013 11.00 am

AGENDA

1. Apologies for absence

2. Matters arising from the minutes of the last meeting (29th January 2012) published in February 2012 edition of Sabrina Times and is also on the website in the Members Section

3. Officers Reports: a. Branch Treasurer b. Branch Organiser c. Other Officers

4. Election of Officers a. Branch Organiser b. Branch Treasurer c. Committee members

5. Other items for discussion

Coffee will be served from 10.00am and we will be going to the Pen and Wig for lunch.

Are there any volunteers to take notes at the meeting? Please contact Janet Hiscott if you are willing to help.

Afternoon programme

14.00 hours

Linda Fowler: 10 years of the Suture on a Shoestring

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