December 2012 Open University Geological Society Severnside Branch
Total Page：16
File Type：pdf, Size：1020Kb
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 that you have borrowed previously. I will bring it along to the AGM in February. Secretary 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 D10 1 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 3 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).