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The Black Country Geological Society August 2009 Newsletter No. 196 The Society provides limited personal accident cover for members attending meetings or field trips. Details can be obtained from the Secretary. Non-members attending society field trips are advised to take out your own personal accident insurance to the level you feel appropriate. Schools and other bodies should arrange their own insurance as a matter of course. Leaders provide their services on a purely voluntary basis and may not be professionally qualified in this capacity. The Society does not provide hard hats for use of members or visitors at field meetings. It is your responsibility to provide your own hard hat and other safety equipment (such as safety boots and goggles/glasses) and to use it when you feel it is necessary or when a site owner makes it a condition of entry. Hammering is seldom necessary. It is the responsibility of the hammerer to ensure that other people are at a safe distance before doing so. Committee Copy date for the next Newsletter is Chairman Gordon Hensman B.Sc., th F.R.Met.S. Monday 5 October 2009 Vice-Chairman Alan Cutler B.Sc., M.C.A.M., Dip.M., M.CIM. Hon Treasurer Contents: Mike Williams B.Sc. Hon Secretary Future Programme 2 Barbara Russell Field Secretary Other Societies 3 Andrew Harrison B.Sc., M.Sc., F.G.S. The Dudley Ikon 3 Other Members The 'Dudley Bug' 4 Bob Bucki Editorial – The Geopark Way 6 Les Riley Ph.D., B.Sc., F.G.S., C.Geol., C.Sci., Field Report - Abberley Hill 8 C.Petrol.Geol., EuroGeol. Lapworth Strikes Gold 10 Graham Worton M.Sc., C.Geol., F.G.S. Geologist Explorers 11 Geobabble 11 Members' Forum 12 -1- The Black Country Geological Society August 2009 Newsletter No. 196 Future Programme Lecture meetings are held at Dudley Museum & Art Gallery, St James’s Road, Dudley, DY1 1HU. Tel. 01384 815575. 7.30 for 8 o’clock start unless stated otherwise. Monday 28th September 2009 (Indoor meeting) Lecture by Graham Worton: Why a Black Country Geopark?- Incredible and Unique Geology of Course! Monday 26th October (Indoor meeting) To be arranged Monday 30th November (Indoor meeting) Members' Evening Gordon Hensman The BCGS stand needs volunteers! We need 3 volunteers at a time. Dividing each day into morning and afternoon sessions makes a total of 12 volunteers. If you can offer your services for one or more of these sessions, please contact Barbara Russell tel: 01902 650168, email: [email protected] Why not visit our website at: www.bcgs.info -2- The Black Country Geological Society August 2009 Newsletter No. 196 Other Societies North Staffordshire Group of the Geologists’ Association Saturday 26th September: Churnet Valley Geotrail (South), leader: Dr Richard Waller. Meet at 10.00am at the Car Park (SK 062432) adjacent to the Ramblers Retreat. For good exposures of the local Triassic sandstones, and the opportunity to visit Toot Hill with its spectacular views of the lower, deeply-incised section of the Churnet valley. Thursday 8th October at 7.30pm, speaker: Dr. Cathy Hollis (University of Manchester) Minerals, hydrocarbon and porosity changes: a short history of fluid flow in Carboniferous limestone. For further information contact NSGGA Field Secretary Gerald Ford, Tel. 01630-673409 or email: [email protected] A field fee of £2.00 is made (for members and non members). Warwickshire Geological Conservation Group Wednesday August 19th: Temple Grafton RIGS with Jon Radley - the site of recent clearing in the Blue Lias Formation which shows Holocene Tufa, perhaps the only exposure in Warwickshire. Meet at 7pm at SP`122 541(This is Sun Cottage, New Road, Temple Grafton) You're always welcome, but it might be good to contact us first in case of change. Email Christine Hodgson [email protected] or Nigel Harris [email protected] You could try 01926 853699 or 01926 5511097. For evening field trips: the WGCG mobile phone will be answered from 11am on the day of the trip. The number to ring is 07527204184 Geological Society, West Midlands Regional Group Tuesday 13th October: Lecture - tba. Birmingham University, Dome Lecture Theatre, Geology Department, 6.30pm For further details contact the Secretary: Adrian Jones, tel: 0121 746 5724 e-mail: [email protected] The Dudley Ikon If Dudley has a symbol which could represent the town to the outside world, it must be the elaborate fountain which stands in the centre of Market Place, now a pedestrianised open space. The work of James Forsyth, something of a fountain expert, in 1867, it shares some of the exuberance of the great Perseus Fountain at Witley Court which was also his work. There, prancing horses rise some 26' above the water level. Here in Dudley, horses rise from the top canopy of a double triumphal arch. The water supply comes in two distinct ways. Water for thirsty horses cascaded into wide troughs on the north and south sides from robust dolphins. Water for passers-by spouted into more delicate bowls from lions' heads. Granite and Carrara Marble are the materials. The fountain was one of the many donations to local welfare by the same Earl of Dudley who provided the theatrical effects for the Murchison visit. His other purpose was Temperance - clean palatable water rather than gin or porter consumed by his local workforce. Heritage Lottery funding has seen it cleaned and restored. ■ Eric Robinson See also Eric's letter in the Member's Forum below. Ed. -3- The Black Country Geological Society August 2009 Newsletter No. 196 Welcome Welcome to the August issue of the Dudley Bug. We were glad to hear that many of you liked our last piece entitled ‘What Is a Geologist?’ Since then we have both graduated from the University of Birmingham with our degrees in Geology and began helping out at Dudley Museum & Art Gallery with the samples collected from the Step Shaft (Graham spoke about this during his talk). In this month’s Dudley Bug we bring you the demise and distribution of the Palaeozoic Coal Swamps plus a swamp themed Wordsearch. Alison and Chris Palaeozoic Coal Swamps In the West Midlands, much of our industrial heritage is based around the abundant coal measures left by our tropical rainforest, 250 million years ago (Ma). In this month's issue we investigate the location of these past coal swamps and how they disappeared. The swamps are referred to as Palaeozoic coal swamps.The term Palaeozoic is an era ranging from 360Ma to 250Ma. This includes the Carboniferous and Permian periods. It is important to note that the Carboniferous is now split into the internationally recognised Mississippian (Early Carboniferous) and Pennsylvanian (Late Carboniferous). (http://www.stratigraphy.org/) These wetland forests were much like the flooded forests of the Amazon today, where they were flooded regularly by the rising tides of the nearby sea forming swamps amongst the twisted roots. Over geological time the large amount of organic matter was buried by subsidence or tectonic activity. As pressure built up with depth the carbon content also increased and a reduction in moisture and volatiles occurred. This process is known as coalification. This means that the organic matter was transformed from peat to brown coal and bituminous coal until it reached the highest carbon rich grade of anthracite coal in certain situations. The result of the coalification process is a carbon rich organoclastic rock formed mainly by the lithified plant remains. The distribution of the Palaeozoic coal swamps was in the hot and humid lowland, tropical setting of around 20º – 30º latitudes. During this period there was a much higher level of atmospheric oxygen in the atmosphere than the present, up to 35%. This amount of oxygen allowed giant insects to thrive such as Meganeura, a dragonfly with a 1 metre wingspan along with a 6 foot long centipede called Arthropleura. The climate at this time was icehouse, meaning there is ice at the caps, cooler temperatures than present dominate with 100,000 year glacial oscillations in the upland regions and poles on the continent of Gondwana. The Earth eventually moved into greenhouse conditions warming much of the globe to desert conditions by the end Permian. ► -4- The Black Country Geological Society August 2009 Newsletter No. 196 Ferns and lycopsid trees that were highly productive in peat formation dominated during the Mississippian forests until the Late Permian in tropical regions of the Earth. The three paleogeographic divisions were the Tropical or Euramerican, the north temperate or Angaran Province, and the south-temperate or Gondwanan Province, found in Europe, North America and Asia respectively. Peat forming tree ferns were the dominant coal sources, except in China where the Lycopsid trees were the main vegetation in the wetland swamps containing 3211 kg of carbon each, of which only 25% was released into the atmosphere. The divisions disappeared at different periods in 3 gradational stages from west to east. There are many theories for the demise of the forests, for example: northward tectonic drift, climate change and vegetation change, all of which would have led to an unsuitable environment for the wetlands of the coal swamps. One of the leading theories for the demise of the ancient forests is the northern movement of the tectonic plates as they moved together to form the super continent of Pangea. This would have essentially dried the forests out. This theory is supported by the appearance of the desert red beds of “New Red Sandstone” in the Permian. The strongest theory is the onset of the Variscan Orogeny in the late Mississippian, early Pennsylvanian eras, also known as the Hercynian Orogeny throughout Europe and eastern North America.