Reports of Meetings
2006 and 2007

Meeting Reports 2006/2007
 

17th Jan, Tue	Colin Humphrey and John Miller - gave an illustrated talk on The Geology of Arran.
21st Feb, Tues	Members' Evening with AGM.
21st March, Tuesday	Dr. David James gave a presentation on "Lode Geometry in the Central Wales Orefield".
SATURDAY 8th April	The famous Aberystwyth Grits coastal section. with Dr. Richard Cave and Dr Bill FitchesTBA
18th April, Tues	Dr. Tom Sharpe talked on "The Geology of Atlantis" the volcanic story of Santorini
Tues 16th May	CHANGED PROG. We had a special sale of about 200 lots, mainly Geology books (Children's, Popular and advanced petrology books.) raised over £300 for club funds
21st May, Sun	Field trip to the Mainstone area led by Martin Allbutt
Tues 20th June	Prof. Cynthia Burek talked on "The History of Women in Geology"
Sun 25th June	Dr Bill Fitches led a trip to Blainau Ffestiniog , visiting the Lower Ordovician/Upper Cambrian sedimentary rocks and igneous intrusions
Sun 23rd July	Tony Thorp led a field trip to Llanfawr Quarry and Cefnllys Castle, near Llandrindod Wells, with the Geology Section of the Woolhope FNC
Tues 15th August	Evening field trip to Gilfach (A44 Roadside Geology) with Dr. Chris Fletcher
Tues 19 Sept	Talk on Victorian Microscopes and their Impact on Geology - Tony Thorp. A wide ranging talk taking in microscope design, refractive indices, manufacture of glasses, devitrification and with lots of microscopes thanks to new member, Mike Woof.
Sun 24th Sept	Field trip to the Forestry road off the A44, leading to Cefn Croes Windfarm, with Tony Thorp. A beautiful section going from the Cwmere to the Devil's Bridge Formations, with lots of interesting structures. Thanks to the Forestry Commission for their permission.
Tues 17th Oct	Members' Evening
Sun 19th Nov	Visit to the National Museum Wales, Cardiff
Tues 21st Nov	Dr Tim Palmer spoke on the petrography of building stones, concentrating on limestones and the microstructures which lead to good or bad weathering. Porosity is the key to understanding. The shelly content of limestones is dense but ooids and fecal peloids have up to 60% micropores (<5µm) which draw in water by capillary action, leading to in-service damage by freezing or dissolution by acid rain. Durable limestones have low microporosity within the particles, and have the macroporosity between the particles occluded (filled and sealed) with spar calcite formed during lithification, at which point any particle microporosity ceases to matter. The strongest limestone - the best of Bath Stone - consists of dense shelly particles, with the intervening macroporosity fully occluded by spar calcite. In-service failure of limestone can also be caused by particle expansion as the sulphide, originally formed by anoxic decomposition of organic matter in the particles, oxidises to sulphate. Strengthening of particles can result from bacterial boring of the particles on the sea floor and subsequent filling of these tiny galleries by recrystallised calcite, forming a strong network.
2007 Tues 16th Jan	Dr Chris Fletcher talked to us on "Kathmandu to Kashgar - a Geological Trek across the Himalaya & Tibet Plateau" This was a three-week journey he led in early summer 2006, travelling 3000 km at altitudes of 4000 m to 5200 m (17,000 feet) north from Kathmandu past the High Himalaya, then west across Tibet, the largest and highest plateau on Earth, so vast and high that it changes the climate of much of the Northern Hemisphere. Many of the rocks encountered have still so far only been poorly described, and in some cases not described at all. The Himalayas were formed when the Indian sub-continent, which had travelled north from near the South Pole, finally collided with the Asian landmass, lifting low-lying land over 8 km; in fact uplift rates still far exceed erosion rates. The peak of Everest is limestone deposited in the long-disappeared tropical Tethys Ocean. The expedition travelled through Tsangpo Valley itself, the scene of the continental collision 40-50 million years ago, a massive fault lineament which can be seen from satellites.
Wed 21st Feb	Following a well attended AGM in our new venue and on a Wednesday, there was an illustrated talk on the Isle of Man, presented by Colin Humphrey, which was visited last year by several club members on a splendid week-long OUGS excursion led by Bill Fitches. Isle of Man was situated on the very edge of the Iapetus suture, and consists mainly of metamorphosed Manx Slate of Early Ordovician age deposited in a deep marine turbidite environment. There are also interesting areas of down-faulted Silurian, Devonian and Carboniferous (the latter sitting on the Manx Slate with a spectacular unconformity). Volcanics are present, and excellent exposures of Caledonian and Tertiary igneous intrusives.
Wed 21st Mar	A Members' Evening discussing our "Land of My Fathers" event, celebrating 200 years of the Geological Society of London
Sun 25th Mar	Field trip to the Ring Hole, near Dolfor, led by Tony Thorp, looking at slumped Ludlow sediments of the Bailey Hill Formation
Thur 19th April	Tony Thorp gave a talk on "Nodules and Concretions
Sun 22nd Apr	Field trip led by Duncan Hawley, of the University of Swansea. Exploring the Silurian on the Wye, "In the Footsteps of Murchison." In 1831 Roderick Murchison ‘discovered’ the first true Silurian dipping gently on the banks of the Wye near Trericket Mill. Fossils confirmed his find. Duncan Hawley followed Murchison’s footsteps using extracts from the original field notes, and looked from Murchison’s perspective on the rocks of the Wye Valley and the Brecon anticlinal. This trip of Murchison, and his excursion into Shropshire a few days later, was profoundly important for the development of Welsh stratigraphy (and, like most other things he did, led to disputes with Sedgwick!). He had found the top of the Silurian Ludlow and now had a marker from which to work downwards. It began the process of ordering the hitherto confusing greywacke rocks of the Welsh Lower Palaeozoic.
Sunday 20th May	Field trip to Brynyrafr mine which provided a remarkable range of minerals, including museum quality Marcasite
Wednesday 23rd May	The Missing Years of Mid Wales geology. Professor John Cope, National Museum of Wales. (LOMF) Fully reported at http://mwgeology.members.beeb.net/copea5.pdf or go to the LOMF page and click on the button
Wed. 20th June	"In the Beginning": The early geology of Mid Wales. Dr. John Davies. CCW reported at http://mwgeology.members.beeb.net/beginning.htm or click on the button on the LOMF page
Fri 29th June to Sun 1st July	Summer field trip to the Lleyn Peninsula reported HERE
Wed. 18th July	A short talk by member. Melanie Dooley -"A dip in the Tethys!", reported HERE
Sunday 29th July	The field trip to Quaternary glacial features was postponed to next year
Thursday 23rd Aug	Joanne Venus (British Geological Survey, Keyworth) talked on BGS mapping in the Welsh Basin District and demonstrated new mapping technology
Sunday 26th Aug	Joanne Venus and Andrea Snelling - (BGS) led a field trip in the Hafren Forest area looking at stratigraphy and graptolites.
Saturday 15th Sept	Dr. Joe Botting led a field trip to Llandegley Rocks - This comprised the older of two Ordovician islands, with lavas, ashes, keratophyres and sandstones. Exciting times!
Mon 24th - Sat 29th Sept	Land of my Fathers An exhibition in the Minerva Centre, celebrated 200 years of the Geological Society Tues/Wed - Were "Schools mornings" with hands on geology for youngsters Thursday - Lembit Öpik M.P. introduced the evening talks. Professor David James talked on the geology of the basin and the ancient sea which formed it and George Hall, the president of the Welsh Mines Soc. talked on the Metal Mines.
Sunday 30th September	A Geological field trip "In the steps of O.T.Jones" to the Rheidol Gorge, was led by Dr. Denis Bates, Central Wales RIGS.
	A trip to Penyclun and Bryntail mines was led by the Welsh Mines Soc. and introduced newcomers and amateurs to these remains of our mining heritage.
Sunday 7th Oct	A field trip to the Caban Coch and Cerrigwynion Quarries was led by Professor David James (LOMF)
Wed 17th Oct	Tony Thorp (Mid Wales Geology Club) talked on The Legendary O.T. Jones: 'Field Marshal' of the Silurian Rocks'.(LOMF)
Wednesday 21st Nov 2007	The talk by Prof. Cynthia Burek, University of Chester was cancelled and Prof. David James talked on "Structural and stratigraphic controls on the location of the Central Wales Orefield(LOMF) For a report click here