Mercia Rocks
OUGS West Midlands Branch Newsletter
Issue No 4 (2016) December 2016
Varieties of Gypsum: Desert Rose, and Satin Spar.
Branch Officers Contents
Branch Organiser – Sandra Morgan Branch Organiser’s report p 2 Branch Treasurer - Susan Jackson Branch AGM notice p 3 Newsletter Editor – Mike Hermolle Field Trip programme p 4
Branch Committee Field trip report p 6 David Green, Portway Hill Dolerite P 10 Alan Richardson Geo-etymology p 11 Rocks Thru the Windscree p p 12 If you would like to join the Other OUGS items p 15 committee please do get in touch Other Societies p 17 [email protected] Standing Order Form p 18
Branch Organiser’s Report
Dear all,
The end of the year is rapidly approaching and we have just one more branch event this season: the Sedimentary Laboratory Workshop led by Alan Richardson on 4 December.
Our previous event was the Mineralogy Laboratory Workshop led by Alan Richardson on 9 October. Once again this was a very popular event, with lots of interesting specimens to investigate. See the report in this newslett er.
The committee has been working on the programme for 2017, and we already have several interesting events confirmed. The first of these is our branch AGM on 28 January 2017. The Lapworth Museum re-opened in June after a major lottery- funded make-over. We will be holding our AGM in the new Lapworth Education
Room, and the AGM will be followed by a free buffet lunch and a tour of the museum – see the AGM Agenda in this newsletter.
The branch AGM is your opportunity to elect your branch committee members for
the coming year, and to give your feedback/suggestions. We would welcome new committee members. Do get in touch with me if you would like to discuss what this might entail.
It is membership renewal time again – subscriptions are due on 1 January. At the Society AGM in April, it was agreed that there would be an increase in the annual subs from £18.00 to £22.00 for Full and Associate members. This increase is very important to the Society. It is the first increase in subs since 2005, thanks to the
careful stewardship of the past and current treasurers. We recommend that you pay by standing order. When you are updating your payment instructions, please make your payment date 1 January, and please provide your membership number as a reference. For full details, including subs for Joint and Family members, and an
electronic renewal form, see http://ougs.org/members/ (scroll down to the bottom of this screen).
And while you are updating your payment instructions, please also check that we
have the correct contact details for you. If there are any changes (name, address, email, phone) do please inform the Membership Secretary by emailing [email protected]
I look forward to seeing many of you in 2017!
Best wishes Sandra [email protected]
Sandra 2 [email protected] You are invited to the
OUGS WEST MIDLANDS BRANCH
ANNUAL GENERAL MEETING
On
SATURDAY 28th January 2017
at 11.30 am
Lapworth Museum Education Room Department of Geography, Earth and Environmental Sciences University of Birmingham Aston Webb Building
Agenda 1 Apologies 2 Minutes of the previous meeting held on 23rd January 2016 3 Matters Arising 4 Officers' Reports 5 Election of Officers * 6 Appointment of Committee 7 Any other business
PLEASE NOTE *Nominations are sought for all posts.
After the meeting a free buffet lunch will be provided in the Education Room After lunch there will be a tour of the Lapworth Museum
For further information about the Lapworth Museum, see the Museum website at http://www.birmingham.ac.uk/facilities/lapworth-museum/index.aspx.
To help with the catering for lunch, please let us know if you will be attending the meeting. Contact Sandra Morgan: [email protected]
3 [email protected] Forthcoming 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. An annual travel insurance may be the best solution for any member who regularly attends field events: this again is a matter of personal choice.
04 Dec Sedimentary laboratory Workshop – Details below Venue: Lickey Hills Visitors Centre
Programme 2017 Sat 28 Jan AGM, free lunch and Lapworth Museum tour. Contact Sandra Morgan [email protected]
Sat 18 Feb Igneous lab. Leader Alan Richardson. Contact Alan Richardson [email protected]
Sun 5 Mar Metamorphic lab. Leader Alan Richardson. Contact Alan Richardson [email protected]
Sat 22 Apr Joint trip with BCGS Mortimer Forest, Herefordshire/Shropshire Border. Leader tbc. Contact Sandra Morgan [email protected]
Sat 29 Apr Field Skills day. Leader Alan Richardson. Contact Alan Richardson [email protected]
12-14 May Society AGM, Walton Hall. See Society newsletter or website.
Sun 2 Jul Lickey Hills. Leader Julie Schroder. Contact Sandra Morgan [email protected]
18-20 Aug Symposium, Edinburgh. See Society newsletter or website.
4 December 2016: Sedimentary Petrology Laboratory Workshop
1030 – 1530 Lickey Hills Visitor Centre, Warren Lane, Lickey, Birmingham B45 8ER The venue is signposted from the roundabout at Junction 4 (Lydiate Ash) of the M5.
This laboratory session will cover the essential elements of describing, identifying and interpreting sedimentary rocks. A range of clastic and carbonate specimens will be provided, along with support materials which will allow individuals to work at their own pace, with the support of the tutor.
4 [email protected] You will need to bring a hand lens and grain size scale. The laboratory booklet gives instructions for the systematic identification of the rocks and pro-forma sheets for each specimen. All students will be e-mailed a pdf copy of the booklet in advance. If you would like a printed copy, please contact the tutor.
The session will take place in the school room adjacent to the visitor centre, where there is a café and toilets. If the weather is good, you may wish to visit the Barnt Green Road Quarry, to see a recumbent fold in Ordovician quartzites (http://ehtchampions.org.uk/ch/?page_id=76). The ground is rough and muddy so please wear appropriate footwear; you will not be allowed to approach the faces unless you bring a safety helmet.
This event is especially suitable for those new to the study of geology, and will provide a good foundation for the field skills day in the Bridgnorth area in the spring.
Handlens: You will need to bring a hand lens. Search on Amazon for a ‘Jeweller’s loupe’, with a magnification of around x10. I found one advertised for £1.57. (http://www.amazon.co.uk/Jewellers-Jewelry-Loupe-Magnifier- Magnifying/dp/B0014R6M1O/ref=sr_1_sc_1?s=drugstore&ie=UTF8&qid=1425996587&sr=1 -1-spell&keywords=jewellers+lupe) …or, for £2.92, you can buy one with built in illumination: https://www.amazon.co.uk/QHGstore-30x21mm-Magnifier-Foldable- Illuminated/dp/B01DELRZTU/ref=sr_1_51?ie=UTF8&qid=1473424349&sr=8- 51&keywords=illuminated+loupe Grain Size Scale: I recommend the ‘University of Leicester Grain Size Scale’, available from Geo-Supplies (www.geosupplies.co.uk) for £1.69.
5 [email protected] Field Trip Reports
Mineralogy Laboratory Workshop - 9 October 2016 Tutor: Alan Richardson Our programme of laboratory workshops is designed to fulfil a growing desire among OUGS members to get formal training in the description and identification of minerals and rocks. Building on the success of last year’s series of petrology workshops, this was the first time we had offered a mineralogy event. It proved a popular addition: with numbers limited to sixteen, it was oversubscribed and late applicants had to be turned away. Participants were sent two illustrated booklets in pdf format a week before the event: one was a simplified introduction to silicate chemistry, while the other explained the techniques and terminology associated with the investigation of minerals in hand specimen.
The workshop booklets
A brief introductory lecture introduced the observations required to identify such properties as form, habit, lustre and cleavage, as well as the practical procedures for the determination of hardness, streak and relative density. The safe testing of specimens with cold dilute hydrochloric acid was described, and then students were briefed on the exercise they were to undertake. Each was given a data sheet bearing a table of the physical properties of 24 mineral specimens. However, there were 100 gaps in the table, including the identity of the specimens and many of their properties. The exercise required the examination and testing of the minerals in order to complete the data sheet and elucidate the identity of the specimens using a variety of reference sources.
Mineralogy Worksheet
Varieties of Gypsum: Desert Rose, and Satin Spar.
Some members worked co-operatively in small groups, while others preferred the challenge of working on their own. The session had started at 10.30, and by half-past two some students had already finished and were able to compare their results with a prepared answer sheet. One or two made an early start for home, while others chose to walk to the nearby Barnt Green Road Quarry to observe a recumbent overfold in the local Ordovician Lickey Quartzite. The rest preferred to adopt a more considered approach, and continued to work at their own pace.
Karen, Zbig and Sally working to identify one of the mineral specimens.
Orthoclase feldspar enclosing quartz and muscovite, and a cleavage fragment of calcite.
The intention is to adopt this event as a regular event in our annual calendar. Refinements are already being made to the support materials, and by next year it is hoped to have an even better selection of specimens for examination.
A twinned crystal of gypsum, and hornblende.
“Great Minerology workshop at Lickey Hills today, really enjoyed it; very informative: nice to get hands on with minerals.” Karen Bose “Mineralogy workshop at Lickey Hills Country Park ... Another successful day's activities from Alan Richardson!” Tom Perkins
Contributions to the Newsletter are very welcome. The subject matter can be anything geological that you think other members would like to read.
Alan Richardson has contributed an article about the Portway Hill Dolerite and I have submitted the first “Rocks Through the Windscreen”
We use photographs at the head of the title page to make Mercia Rocks a little bit more interesting, attract your attention and show some geology. I need more pictures! Email (to [email protected]) your favourite (preferably local) picture and I will include it in a future issue. It can be a distant general view, or a close up.
Mike Hermolle Items for inclusion in the next Newsletter, by email to: [email protected] by 28 February 2017
9 [email protected] Portway Hill Dolerite
Photograph 1. Portway Hill Quarry. Direction of view: northwest. Dolerite, with well-developed spheroidal weathering is cut by a dark, sub-horizontal band (arrowed).
During recent conservation work at Portway Hill in Oldbury, I was intrigued by a narrow, dark, sub-horizontal band cutting across the outcrop (arrowed on Photograph 1). While I cleaned the beautiful spheroidal weathering in the dolerite, my attention kept returning to the band. No-one could offer an explanation for its origin, so I was left to conjure my own. It is coarser than the dolerite above and below, but although it is deeply weathered and very friable, its crystalline nature is still apparent. It is mafic and contains obvious white phenocrysts which are likely to be plagioclase feldspar. The upper and lower margins of the band are not parallel: the upper margin has more peaks and troughs than the lower, and these undulations have a consistent asymmetry. The mafic composition suggests a magmatic rather than a hydrothermal origin. However, if it was an intrusion through an Photograph2. Spheroidal older consolidated dolerite, its large surface area would have weathering in the dolerite led to rapid cooling and a very fine grain size. In addition, the exposure. undulations in the upper and lower margins would mirror one another. It therefore seems likely that the dark band is a cumulate formed by fractional crystallisation and crystal settling. For this to be true, the dolerite exposed in this outcrop must represent two distinct intrusions. The rock below the band would be the earlier emplacement. Once cooled and solidified, it would have been followed by a second intrusion of magma that had resided at depth sufficiently long for relatively large crystals to form during slow cooling. After emplacement, the low viscosity associated with mafic magmas would have allowed these crystals to settle downwards to accumulate as the layer now observed.
Photograph 2. Enhanced photograph of the dark band, showing its mafic nature, coarse grain size, white plagioclase crystals and asymmetric undulations on the upper margin.
This being so, it conjures a possible explanation of the asymmetric undulations on the upper surface of the band. Magma moves in intrusions: if there are accumulations of loose crystals, they
10 [email protected] will be moved in the same way as sand in a current of water, and will develop analogous structures (there are many examples of cross-bedding in layered gabbro intrusions). As viewed in outcrop, each undulation slopes gently to the left, and steeply to the right. If these are indeed current- formed asymmetric ripples, they must be the result of magma flowing through the intrusion at this point from left to right. The decayed state of the rock prevents retrieval of a specimen for thin section preparation, so it will not be possible to identify any of the small-scale textures characteristic of cumulates. If the observed structures are asymmetric ripples, they will extend back into the outcrop, and will be preserved as sole marks on the underside of the overlying dolerite. Removing a small part of the band under one of the undulations would confirm its three-dimensional shape. This site lies within the Rowley Hills Nature Reserve: park at the bottom of St Brades Close, Oldbury, West Midlands B69 1NX. An obvious path crosses the grassy area on the left: follow it as it turns right, behind the houses, and then take the left branch which leads downhill to the exposure. Alan Richardson
Geo-etymology
In this issue a couple of simple words. We know what they are, but where do the words come from? Barite (previously barytes) – from the Concise Oxford Dictionary of Earth Science:
Mineral BaSO4 orthorhombic; colourless to white, often tinged brown, yellow, blue, green and red…occurs as a vein filling. The OED: Modified from the Greek βαρύς – heavy, in reference to its great weight, partly assimilated to names of minerals in -ITES. All those words beginning with baro or bary (eg barometer) have similar connotations with weight. One of the earliest pebbles I picked up contained a lot of barite and was very obviously heavy for its size. Basalt - from the Concise Oxford Dictionary of Earth Science: A dark-coloured, fine-grained extrusive igneous rock. The OED: From the Latin basaltes, long used unchanged in English. According to liny originally an African word. (Now that’s interesting – Mike) A kind of trap rock; a greenish- or brownish-black rock, igneous in origin….(Pliny’s basaltes was probably a variety of syenite) Mike Hermolle
Rocks through the Windscreen – geology from the car
11 [email protected] (but not for drivers!)
A4117 Cleobury Mortimer (River Rea-SO67967632) to Ludlow (A49-SO52317553)
©Crown Copyright. Reproduced by permission of Ordnance Survey® Track and profile produced with a Garmin etrex 30 GPs and Memory-Map. In this hilly part of south east Shropshire the River Rea, a tributary of the River Teme, is fairly deeply incised into the rocks of the Cleobury Basin. This is a rather deformed elliptical syncline comprised of interbedded sandstone and siltstone - the Clee Formation of Devonian (Upper Old Red Sandstone) age. Roughly centred on the south of the town the syncline is unconformably topped by Lower and Middle Coal Measures. The local sandstone can be easily seen in some of the buildings such as the Church of St Mary the Virgin and the Market Hall. There is a great deal of clay in the area which was used in brickmaking as can be seen by the presence on old OS maps of brick works just off the main road close to the traffic lights.
The road through the town is an almost continuous rise reaching an initial summit of 200m after about 4km where the bulk of Titterstone Clee Hills almost covers the width of the windscreen with Hanson’s quarry slightly left of centre.
Clee Hill from the east.
By this point the underlying bedrock is St Maughans Formation (a red-brown mudstone with beds of sandstone, conglomerate and calcrete. After crossing another deeply incised valley at Hopton Wafers the climb becomes steeper and finally at Foxwood the road makes a sharp turn to the southwest to pass around the shoulder of Clee Hill on the Lower and Middle Coal Measures (mudstones, siltstones and seatearths), crossing the basal sandstone and Cornbrook Sandstone which is equivalent to the Millstone Grit. On the left as you round the hill it is possible to see the Abbeley Hills, Malvern Hills and deep into Wales.
The hillside displays a great deal of evidence of industry with uneven ground and loose blocks (not roches moutonée although there are plenty of moutons about!). The Hills were exploited for hundreds of years for their iron ore, lime, coal, clay and rocks. The rocks excavated were the basalt (more correctly olivine diorite), known as Dhu stone and granite. The Hills were of such importance that they are the only British hills shown on the Mappa Mundi ((Jenkins, 1982). The Titterstone Clee basalt “…lies chiefly within the Coal Measures” (Haines & Horton, 1969) and has been extensively quarried for roadstone. Toghill, 2006 describes the carboniferous limestone as being folded into a gentle syncline with a northeast-southwest axis and in the south the limestone resting unconformably on the Silurian Raglan Mudstone.
With the road now moving round to the west and, leaving the LMC, the descent begins down Angel bank, over conformable layers: - St Maughans Formation, the Bishops Frome Limestone, possibly indicated by a short change in slope, and conformably onto the Raglan Mudstone. During the early part of this descent the rocks of the Ludlow Anticline can be clearly seen looking along the axis of the anticline. The road joins the A49 in a broad valley created by he retreat of the Devensian ice sheet and changing watercourses of the rivers, Teme, Corve and Onny. The most spectacular view of Titterstone Clee is more or less over your right shoulder about 1km before you reach the end.
Titterstone Clee from the west
13 [email protected] References: Haines, B. and Horton, A. (eds.) (1969) Central England, 3rd ed. Keyworth, HMSO. Jenkins, A. E. (1982) Titterstone Clee Hills: Everyday Life Industrial History and Dialect, Ludlow, A.E. Jenkins. Toghill, P. (2006) Geology of Shropshire, 2nd ed. Marlborough, Crowood Press Ltd.
There is more information on the Clee Hills in the references and an early explanation of the emplacement of the dolorite in Murchison’s Siluria which is available in Worcester Library, Birmingham University Library and online at https://play.google.com/store/books/details?id=cKlAAAAAcAAJ&rdid=book- cKlAAAAAcAAJ&rdot=1
New Geological SSSI
The story of England's newest geological Site of Special Scientific Interest – in north Bristol – is told in issue 4 of Earth Heritage Extra which you can download free from http://www.earthheritage.org.uk/ehextra/EHE4-10-16.pdf.
Other OUGS items
IMPORTANT ANNOUNCEMENT
INCREASE IN MEMBERSHIP SUBSCRIPTION RATES
At the Society AGM, held on 16th April 2016 in Scarborough, the Members voted to increase the membership subscription rates from the 1st January 2017. The increases are: Single membership from £18 (€21) to £22 (€27) Joint membership from £26 (€30) to £32 (€39) Family membership remains unaltered at £2 (€2)
MEMBERS ALREADY PAYING BY STANDING ORDER Now is the time to change your Standing Order, do not leave it till later, you may forget! If you use electronic banking, you can do this on-line or otherwise visit your bank branch. a) Calculate your new subscription amount b) Ensure that the payment date is 1st January – not in December, or later in January, and definitely not in February or March (see Note 1 below) c) Ensure that your membership number (or membership numbers in the case of Joint Members) is in the reference field (see Note 2 below).
MEMBERS WHO DO NOT PAY BY STANDING ORDER Why not take this opportunity to set up a Standing Order? You can find a Standing Order Mandate form on page 10 of this Newsletter. If you do not want to set up a Standing Order please remember to make your subscription payment by 31st January (see NOTE 1 below) and ensure that your membership number is quoted (see NOTE 2 below).
Note 1: At the AGM it was proposed that a Constitutional change should be raised at the next AGM (13th May 2017 in Milton Keynes) to change the final subscription renewal date from 31st March to 31st January and that this would come into force in 2018. This would mean that in 2018 any member not renewing by the 31st of January would cease to be a member on that date, and therefore, would not be entitled to a copy of The Proceedings; which is generally sent to the printers in February.
Note 2: The membership number is very important as some subscription payments are made from non-members accounts and the actual members cannot be identified. There have been numerous occasions in the past where this has occurred and it is a lengthy process to identify the member.
If you cannot remember your membership number, please contact the Membership Secretary at: [email protected] Please advise the Membership Secretary of any change to your name, address or email address. This is important because undelivered Newsletters and OUGS Proceeding will not be forwarded at the Societies expense.
Open University Geological Society East Midlands UK Hazards Day of Talks, Saturday 10 December 2016, 10:00 to 16:45 British Geological Survey Conference Centre, Keyworth, Nottingham Programme (provisional)
10:00 am Registration and coffee
Dr Vanessa Banks, What do we want from a sinkhole 10:45- 11:30 British Geological Survey database?
Jonathan Moles, 11:30 – 12:15 TBC (Topic: Tindfjallajökull volcano) Open University
12:15 – 13:15 Lunch (included) and a chance to stock up at the BGS Geology Shop
Professor Doug Wilson, 13:15 - 14:00 Flooding: improving our resilience Environment Agency
Dr Claudia Lally, 14:00 – 14:45 Government Office for TBC (Topic: Space Weather) Science
14:45 - 15:15 Coffee
Dr John Hillier, Multiple inter-dependent hazards in the 15:15 - 16:00 Loughborough University UK: Something to worry about?
Dr Helen Reeves, 16:00 - 16:45 TBC (Topic: Landslides) British Geological Survey
Cost: £8 per person (including buffet lunch) The facilities have lifts for disabled access and an induction loop for people with hearing aids. Directions at www.bgs.ac.uk/contacts/sites/keyworth/home.html
Please register by 10 December.
For further details contact Don Cameron [email protected]
Other Geological Societies in the West Midlands Please see the individual websites for events
Black Country Geological Society For details go to www.bcgs.info Lecture meetings are held at Dudley Museum & Art Gallery, St James’s Road, Dudley, DY1 1HU, 7.30 for 8 o’clock start unless stated otherwise. Those wishing to attend field meetings please contact the Field Secretary, Andy Harrison email: [email protected]
Shropshire Geological Society For details go to:- www.shropshiregeology.org.uk/SGS/SGSintro.html Lectures are held at Shire Hall, Shrewsbury, commencing at 7.15pm for 7.30pm A nominal charge is levied for attendance by non-Members.
Warwickshire Geological Conservation Group For details go to www.wgcg.co.uk/ Lectures are held monthly from September to April, Starting at 7.00pm free to WGCG members with non-members £2.00 per lecture.
North Staffordshire Group of the Geologists’ Association For details go to www.esci.keele.ac.uk/nsgga NSGGA is the regional group of the Geologist Association North Staffordshire. The winter lecture programme takes place on the second Thursday of the month from October to March at 7.30pm. All talks are held in the William Smith Building, Keele University.
Woolhope Naturalists Field Club For details go to www.woolhopeclub.org.uk The geology section of the club is an affiliated member of the Geologist Association. Lectures are held in the Woolhope room, Hereford Library Broad Street. Field trip programme also available. For further information on all events email Sue Hay [email protected]
Teme Valley Geological Society For details go to www.geo-village.eu Meetings generally held at Martley Memorial Hall Martley Worcestershire
A New Geological SSSI
The story of England’s newest geological Site of Special Scientific Interest in north Bristol is told in issue 4 of Earth heritage Extra whaich can be downloaded free from http://www.earthheritage.org.uk/ehextra/EHE4-10-16.pdf.
The Open University Geological Society
STANDING ORDER MANDATE Please complete and send to your own bank To ...... Bank ...... Branch Please pay BARCLAYS BANK, CHESTER BRANCH Sort Code 20-20-46 For credit of the OPEN UNIVERSITY GEOLOGICAL SOCIETY Account No. 50083771 On 1st January ..... and thereafter on 1st January annually until further notice. The sum of £.... Amount in words ...... Reference ...... Please ensure that your Membership Number(s) (and name(s) if possible) are clearly visible in the Bank's Reference above. Full Name(s) (BLOCK CAPITALS) ...... Your Sort Code ...... Your Account Number ...... Signature ...... Please cancel any existing Standing Order payable to the Open University Geological Society