Barnt Green Road Quarry

As volunteers we were given the opportunity to attend training days. We had an introduction to the basics of geology; training in the use of tools, vegetation clearance, health and safety, and recruitment of more volunteers. We were invited to undergo a two day first aid course, an opportunity I felt was certainly too good to miss. We also had the opportunity to attend longer courses in geology, and events where we could ‘network’ with Champions from other sites.

I am one of the Champions for the Warren Lane and Barnt Green Road Quarries in the Lickey Hills. The Warren Lane quarry is used as a depot and is not permanently open, but the Barnt Green Road Quarry is one of the ‘jewels in the crown’ of the entire Champions project. It is known that this quarry provoked some geological interest in the late 19th century for its dramatic structure, and now, its superb overfold in the Ordovician quartzite has been clearly revealed once again. Certain exposures at the southern end of the quarry have caused speculation within the professional community about a possible connection with the Barnt Green volcanics exposed to the south of the Lickey Hills. Thin sections have been taken for analysis and many questions have been raised for further research.

Champion's project leaflet

We were initially a group of 5, ranging from students to retired and from backgrounds as diverse as you could imagine, but we pooled our ideas to make a success of our project. Eve, noted our ideas and incorporated them into the professionally produced information panels and information booklet. Way markers bearing the Champions logo were installed, and the site was made safe for visitors. In preparation for our launch event in July, we collected rock samples of all the local rock types to be put on permanent display in the Lickey Hills Visitor Centre. We created activities for children, including a quiz to focus their minds along the trail to the quarry.  We were very proud that the Lickey Hills Champions project was selected by The Geological Association as a flagship site for a fieldtrip during its meeting to discuss ‘Geoconservation for Science and Society: An agenda for the 21st Century’. The project is deemed to have been particularly successful in achieving ‘community impacts’, particularly in attracting a broad demographic of volunteers, and in achieving a high level of community cohesion.

There are currently 86 volunteer ‘Champions’ spread across the 19 sites, I can highly recommend getting involved. Since becoming a ‘Champion’, I have learned new skills, made new friends, become immersed in the geology of my site, and lots of new doors have opened. A list of the sites can be found on the Champions web site (details below).

For further information visit the H&W EHT’s web site: www.earthheritagetrust.org or the Champions web site: http://champions-earthheritagetrust.org/?cat=3

If you are interested in becoming a volunteer ‘Champion’ in your area or would like to visit one of the Champions sites, please contact the EHT on 01905 855184, email: eht@worc.ac.uk or contact the project manager, Eve Miles by email: e.miles@worc.ac.uk

By
Julie Schroder
BCGS Member

The Black Country is an area located just to the northwest of Birmingham right at the heart of the UK. It includes the towns of Dudley, Walsall and Wolverhampton and is noted for its industrial past. It is so named because of the concentration of mining, iron production and metal working in the area. There is significant evidence for the Black Country to lay claim to be the home of the industrial revolution. The earliest reference to mass iron production in the Black Country is a factory located in Wednesbury during the 1400’s. American visitor, Elihu Burritt was so impressed with what he saw in 1869 he said “The Black County, black by day and red by night, cannot be matched for vast and varied production by any other space of equal radius on the surface of the globe.”

This legacy began back in 1598 with the birth of Dud Dudley, son of the Earl of Dudley. Dud attended Balliol College, part of Oxford University until his father’s business was struck by financial troubles. He then returned home to help run his father’s foundry. History was then made by the discovery of coal as a successful fuel to smelt iron, rather than the dwindling supply of charcoal fuels due to the timber being used for ship production. His success led to a patent from the King around 1620 for the process used in the factory located at Pensnett Chase, near Himley Hall in Dudley. Dud produced a record 7 tonnes of iron per week. This process was later developed and refined by Abraham Darby who was born at Wrens Nest Manor in 1678. Abraham had a factory in Coalbrookdale in 1709 and used coke as a fuel.

What is now left of the Lower Quarried Limestone after the mines closed

Dudley’s limestone has been mined for centuries for use as an agricultural fertilizer amongst many other uses. The Black Country continued its influence on industrial developments as limestone was discovered to be a very successful flux in the iron smelting process. For this reason, the Wrens Nest limestone mines produced up to 20,000 tonnes annually. The mines extend thousands of metres underground and formed a honeycomb network of caverns supported by huge pillars of rock. Dudley’s mine supporting rock pillars are unusual as a majority do not support vertically but are inclined, and some are almost horizontal due to the near vertical dip of the rocks known as the Much Wenlock Limestone Formation in certain areas. Many of the underground mines are connected by canals, and the only way to enter the caverns at the present is by canal barge since many of the original entrance shafts have been sealed up. The canals were the main transport route for the coal and limestone, they linked the mines to the furnaces. Many of the early canals were only created to allow passage for the heavy coal traffic.

The final limestone was excavated from the Wrens Nest in 1924. As a result the mines have been left for nature to dominate once more. The Seven Sisters daylight gallery is an open air mine which has been stabilised with tonnes of an intrusive igneous dolerite hardcore, but many of the underground mines have collapsed as the last miners robbed the final supporting pillars during their retreat. 70 meters beneath the Wrens Nest National Nature Reserve is the Step Shaft mine, adjacent to the largest unsupported underground canal basin in the UK. In the basin there are original 200 years old timbers, nails, plateway rails and even cart wheels which are extremely well preserved due to the wet, low oxygen environment. Cathedral cavern and the Minstrel Gallery (South workings of Wrens Nest East Mine) adjacent to the canal basin were in filled with sand in 2009 to prevent the walls collapsing and losing this spectacular cavern. It is claimed to be large enough to fit the volume of St Paul’s cathedral inside, this is certainly the case for the larger Dark Cavern. In the future the aim is to reopen Cathedral Cavern as part of the Strata Project, which will allow visitors to explore our hidden past through a visitor attraction allowing access to these underground wonders via canal boats and underground lifts, providing the funding can be found one day.

Step Shaft Canal Basin below the Wrens Nest, photo by G. Worton

Chris Broughton
Geologist
Wolverhampton Art Gallery

Dolomite and Calcite 006988

A favourite word of mine however, is PENECONTEMPORANEOUSLY. Perhaps not a Technical term, but an adverb that I have only see used in a geological context. Indeed, I have only seen it used in one situation and that is to describe the formation of Dolomite on the sea floor. In a calcite mud the CaCO3 minerals are replaced by dolomite soon after deposition, i.e. penecontemporaneously. It means; ‘pene’ – almost, and ‘contemporaneously’ – at the same time as, so it describes very early diagenesis. * But this is not the only merit with this word. It is very useful in long word contest having 21 letters. It can also come in handy if you have young children; “If I beat you at hangman, you go to bed!” *Maurice Tucker: Sedimentary Petrology (Second edition): p148.

It is not just words, what about technical terms. Every subject or organisation seems to have to change the terminology for no particular reason, except perhaps to confuse. Education is particularly bad at this: your are in year 9 instead of the third year, and there is now an examination ‘specification’ instead of a syllabus. But geology cannot be excused entirely from this. Having learnt a host of fossil genera in the sixties, I now find that they have mostly been revised, I am sure, for perfectly good reasons. But I miss some of the old names; the big rugose coral in the Wenlock will always be Omphyma subturbinata to me, a tough sounding name that has been replaced by the weak Ketophyllum subturbinatum. Likewise the brachiopod Conchidium knighti is now Kirkidium knighti. However, the one we really should be campaigning about -letters to your MP etc- is another brachiopod Gypidula galeta. Its old name was Pentamerus dudleyensis!!

The most ridiculous use of a geological term I came across was related to me by a geologist specialising in geomorphology. He said that he was struggling through a paper by an American Earth Scientist that was written in the most convoluted language possible, using the maxim; ‘never use one word when six will do the job’. He started to come across the expression; ‘the free air interface’, and after a while he realised that the writer was referring to the ground! Keep your feet on the free air interface!!

Fossil in Micrite 003587

Geology has always been striving to standardise its terminology so that we are all using the same language, and this has been accepted as being generally worthwhile and sensible. We have seen ‘felspar’ become ‘feldspar’, ‘barytes’ replaced by ‘barite’, and there are many others. Sometimes a revision can be problematical. Sedimentary rocks were described using the standard terminology, mudstone, sandstone, conglomerate etc, with adjectives used in a random way. So you could have a ‘quartz sandstone’, ‘feldspathic sandstone’ and ‘calcite mudstone’. As the study of sedimentary rocks moved away from the purely descriptive a new set of terms emerged, so a calcite mudstone would be a ‘micrite’ or a ‘calcilutite’. You could describe the grain sizes using, lutite, arenite and rudite, for mudstone, sandstone and conglomerate respectively, and instead of the adjective use a prefix. Siliceous rocks could have ‘sili’ on the front, and the limestones could have ‘calci’ as a prefix. So we now have standard terms such as calciclastic, calcilutite, calcarenite and calcirudite. The siliceous rocks, however, proved to be more of a problem, siliclastic is widely used, but sililutite and siliarenite are not so accessible, and as for silirudite, there was no future.

Written by Bill Groves
BCGS Member

A Granite Erratic anvil

Each area of the Black Country has always been associated with its own specialised trade and Bloxwich is no exception, having long been a supplier of metal components to the Leather Industry of Walsall. In particular a small area to the north of Bloxwich known as ‘The Short Heath’ or ‘Bloxwich Green’ was associated with the production of awls, (a needle type tool used to punch holes through leather), plus bits and tackles used in the production of horse harnesses and headgear. What is not generally known is that Glacial Erratics collected from local fields were used by these metal workers as mounts for the anvil on which items were forged and honed. This association is commemorated in the collection of Glacial Erratics displayed in the park at the north end of the High Street just before The Bell public house where the Wolverhampton to Lichfield road crosses the A34.

The story of the erratics

These Erratics clearly show the chiselled holes into which the anvils would have been mounted, and presumably by their weight and mass added extra stability to the anvil as it was used to form the metal components required by the leather trade.

A monument to the Erratics

Today these Erratics are preserved in an almost ‘Gaudi-esque’ sculpture and are yet again a reminder of the fact that for the Black Country industrial endeavour cannot be separated from its geological past.

For further information see: http://www.thebloxidgetallygraph.com/anvilstones.htm

Written by Mike Williams
BCGS Treasurer

Essexite by zeesstof via Flickr

Petrology deals with the origin, composition, structure, and alteration of rocks. To do this geologists slice up perfectly good wild rocks into extremely thin sections, thin enough for light to pass through the minerals. Once the sections have been glued to glass slides, they can then observe the mineralogical make-up of various rocks. Igneous rocks in particular can be very spectacular under cross polarised filters within the microscope. When viewed under crossed polars some minerals can be very colourful, for example Olivine can be yellow, red and blues; this is called birefringence. To see the different colours from the minerals you must twist them around on the microscope the change in angle shows different colours. Quartz, which is colourless under crossed polars, becomes dark (or black) at certain angles, this is called extinction. Because this extinction (dark area) moves across the quartz crystal in a wave-like fashion as opposed to the whole mineral becoming dark, it is called an undulose extinction.

Those of you who have studied geology will know the feeling when spending hours at a petrological microscope looking at slide after slide as part of a study. Imagine then the reaction of the geologist when a smiley face presented itself. This is exactly what happened to a researcher looking at a thin-section from the volcanic deposits on Santorini. This accretionary lapilli or coarse ash had this happy olivine crystal. About 2mm across, in a groundmass of rectangular plagioclase laths, larger pyroxene crystals and volcanic glass that appears black on the slide. This erupted onto the cinder cone 54,000 years ago.

An Olivine mineral smiles back

Written by Bill Groves and Chris Broughton, picture and information from David Miller.
BCGS Members

Quartzite summit of the Stiperstones

0315 off goes my alarm. 0400 jump in the car to travel to the start point of the 36 mile Shropshire Six Summits Challenge 2011. By 0545 the team of four is ready to go. At 0600 we had reached the first summit of Corndon Hill (513m), this is a frozen granite magma chamber across the welsh border. A short walk across the valley is the Ordovician aged Stiperstones (536m). These hills form a long craggy ridge of steeply dipping sparkly sandstone deposited on the southern hemisphere in a shallow ocean. Local mining for Galena and Sphalerite has been a way of life at Snailbeach since Roman times until 1919 when the mines finally closed.

As we pushed onwards towards the Long Mynd we climbed upwards to the third summit of Pole Bank (516m). The Long Mynd contains rocks from the Precambrian period when the land was 60⁰ south of the equator. Sediments such as sandstone and muds were laid in an estuarine environment, and even preserved ancient raindrops! Distant volcanoes occasionally created ash clouds over the estuary forming bands of ash in the sands. We continued to drop down into the fantastic Cardingmill Valley by midday to meet up with the support crew.

At 1230 the team reached the fourth and arguably the hardest summit of Caer Caradoc (459m). This climb is not for the faint hearted due to the incredibly steep flanks on this Precambrian volcanic outcrop. The vesicular (bubbly) rhyolite is part of the Uriconian Volcanics. The rocks have bubbles because they were erupted from a nearby volcano, now eroded away. The reduced pressure during eruption causes gases to fizz just like opening a bottle of pop. This volcanic activity caused huge cracks in the crust, for example the famous Church Stretton fault which is still very active today. A line of hills marks the fault, best viewed from the summit. Caer Caradoc was once a hill fort said to be the last stronghold of Caradoc or Caractacus who led a revolt against the Romans.

The summit of Brown Clee used to be Britain's highest coalfield

Finally lunch was upon us and we had a well deserved rest, but as they say ‘no rest for the wicked’ we had a challenge to complete! The team continued towards Wenlock edge, unfortunately losing a team member through injury. We attacked the dipping beds of the Silurian aged tropical reef of Wenlock limestone…sadly with no time for fossil hunting.

By 1700 we had began the accent to the highest point of summit  5, Brown Clee (540m). Brown Clee is composed of Devonian Sandstones, deposited on the southern shore of a huge continent with winding rivers bringing the sand from the mountains to the north. Once, this hill was Britain’s highest coalfield leaving a legacy of mining scars on the landscape. The harder dolerite rocks were also taken creating the many depressions across the hill.

The team on Titterstone Clee

Finally in a stones throw of the finish we dropped down into the valley steaming towards Titterstone Clee (533m). I became increasingly conscious of completing the walk in less than 14 hours, so summoning the last of my energy I began to run up the last summit. Titterstone Clee’s Carboniferous coal deposited in equatorial swamps was mined for hundreds of years. Today quarrying concentrates on the hard volcanic dolerite used as road stone which was injected into the sediments. This protective volcanic cap has slowed the rate of erosion allowing the Clee’s to be the highest hills in Shropshire.

I eventually completed the walk in less than 14 hours with the remaining team members finishing 25 minutes later. So far we have raised £500 for the Severn Area Rescue Association to help Wyre Forest Rescue Station purchase essential life saving equipment. If you would like to support us please visit this link at Justgiving.

 Chris Broughton

SARA Wyre Forest Crew

Geologist

At first I couldn’t bring myself to part with my hard earned cash until… Sat on a traders stall next to a small ichthyosaur vertebra, there was the least aesthetically pleasing, dull, blob shaped piece of rock. I had heard about the rare fossil pinecones found in Argentina earlier that day and enquired to see if this was one. To my amazement, this was a complete Jurassic pinecone from Patagonia, Argentina! Instantly my hands had already purchased the pinecone before I could stop myself and I felt a pain in the wallet. I later researched the specimen on the internet and found that the Argentinian government have stopped the export of the pinecones and the only ones available today were exported before the ban.

The silicified pinecones come from the limbs of giant monkey puzzle tress called Araucaria and Paraaraucaria from Cerro Cuadrado, Patagonia, Argentina. A circular scar on the top shows where the cone attached to the stem. Unfortunately, collecting and exportation of these specimens is now banned by the Argentine Government. 

Chris Broughton
Geologist
Wolverhampton Art Gallery

Martin McMeekin

Our second guest blog describes how a local enthusiast Martin, began his journey along the rocky road of geology.

For me it started at a young age, I used to get curios and excited at the site of exposed rocks. When I was out with my dad in the car, I used to look out the window at the red sand stones at Bridgnorth, or at the exposed limestone as we drove over Hurst Hill on the way to Sedgley. I wondered why they were there and not in my back garden?
      
The first fossil I ever found was in a wood close to my house, I was about 10 years old. I think it was a small sea shell fragment in a piece of red shale and I can’t for the life of me remember what happened to it. Fossil hunting was rather a hit and miss affair for a while as the places I tended to look for fossils didn’t have any fossils to find! Things did improve though when I was much older and by then married, with two holidays, the first to Weymouth and the second to my fantasy home town of Lyme Regis (just as soon as I win the lottery!). It was at this point that I began to look at books in order to direct me to the best fossil gathering rocks.
        
Another early age rock related obsession of mine stemmed from the first time I saw the bright multi coloured ropes and shiny ironmongery of the people who clambered all over them. I would sit in front of the TV watching famous rock climbers like Joe Brown and Chis Bonington and think ‘I wish I could do that’. I was lucky when a chance conversation with a new neighbour to the street where my wife and I were living in 1992 introduced me to a climbing club. This in turn introduced me to the rocky outcrops of the Peak District and North Wales.
        
When your nose is only 15cm away from a piece of rock as you try to find a way up it, you sometimes wonder about how it all got there. A massive change in our family circumstances in 2004 led to me having some extra time to myself in the evenings. This coupled with the Open University sponsored TV show Coast, and my climbing partners graduation from the same university led me to wonder if I could have a go, the subject was obvious. So here I am floundering halfway though an OU degree in Geosciences thinking that I haven’t really got the time to write this, but then the stuff I have learnt, I think that it’s a story worth telling.

By Martin McMeekin,

Willenhall, West Midlands

If you wish to submit a short blog about a geological or personal subject to “Geology Matters” please e-mail it to Christopher.Broughton@wolverhampton.gov.uk

Although I have lived on the edge of the Black Country for almost 25 years I ‘ve never visited Barr Beacon or Barrow Hill before. Actually if I’m honest I’d never even heard of them until a few weeks ago when Graham Worton, Keeper of Geology at Dudley Museum Service, suggested they were important places to learn about the geology of the Black Country.  As a non-geologist, I had no idea what to expect when Graham described them as old aggregate quarries – my first question was “What is an aggregate?”; not just some simple sand and gravel as I later found out.

But back to last week’s field trip…

Sandstone cliff, Barr Beacon

Our first port of call was Barr Beacon, near Walsall.  Travelling on the coach I was surprised how we suddenly turned off the typical busy Black Country road onto a narrow country lane – not the sort of surroundings conjured up by the name “Black Country”.  Barr Beacon is actually in the middle of the countryside with amazing views across Walsall, Wednesbury and West Bromwich. We didn’t have long to admire the views as Graham led us down the hillside until we eventually found ourselves standing below a sheer sandstone cliff.  Graham told us that the lower part of the cliff was made from red Permo-Triassic sandstone with pebble beds, topped by a mixture of glacial sand and gravels.  The pebbles ranged in size from under a cm to fist size. These pebbles come in lots of colours – brown, red, cream, white, but they all had one thing in common…they were all round and smooth from weathering and erosion.

Pebbles

Graham explained that the sand’s colour and layering tells us that it formed somewhere hot. Graham then went on to tell us that when the rocks formed they weren’t where the Black Country is now, but near the equator. Slow movements of the Earth’s crust over geological time meant that it ended up here where we live today; which takes some thinking about!  I did know that the Earth’s landmasses had moved around and the continents we know today didn’t exist in the past, but it’s one thing to read about it and another to be standing somewhere that was originally on the equator.

Barrow Hill rocks

Next stop Barrow Hill, another place with amazing views; from the top you get a 360⁰ panorama of the Black Country.  Again Graham led us off down the hill to an entrance that took us to the centre of the volcano – for that is what Barrow Hill is, an extinct volcano.  The rocks here were completely different from Barr Beacon, not red but black, not soft and crumbly but hard with vertical fissures. The rocks at the centre of Barrow Hill were originally the molten core of the volcano which cooled and solidified over millennia. At the base of the quarry cliff we could see mounds of this rock which had been broken into sharp, angular fragments; quite different to the smooth stones of Barr Beacon.

Aggregate Barrow Hill

Our final stop was underground inside Dudley’s Limestone Caverns to see yet another different type of rock; the cream coloured limestone which was mined here. We also found out about the renowned Victorian geologist, Sir Roderick Murchison who visited the area in the early 19^th Century (you can find out more about Sir Roderick by watching the video blog on this website).

I hope I got all my geological facts correct but if I haven’t please leave a comments below.

With thanks to Graham Worton and Alan Cutler for leading the trip and to the Aggregates Levy Sustainability Fund and Natural England for sponsoring the trip.

If you want to find out more about the Black Country Aggregate sites please visit the Black Country Atlas online or for more information about local sites of geological interest visit the West Midlands Geodiversity Partnership website.

Linda Ellis

Project Manager
Wolverhampton Art Gallery

Granite and Microgranite from Scotland

Igneous rocks are hot molten rocks which rise towards the surface. The term igneous originated from the Latin term ignis which means ‘fire’. In order for them to begin to melt temperatures can be anything from 700°C.

They begin to melt down within the deep crust or upper mantle and because the molten rock has a lower density (is lighter) than the surrounding solid rock it begins to rise through cracks within the solid rock.

Once they are near the surface they either erupt through a fissure or volcano (such as in Hawaii or Iceland) or stop just below the surface within the crust where they crystallise. They are either intrusive (solidify quickly within the crust) or extrusive (solidify slowly on the surface). The most common extrusive igneous rock is basalt which is erupted through fissures or volcanoes and the most common intrusive rock is Granite.

Igneous rocks are likely to contain one of the common minerals associated with igneous  rocks; these include quartz, mica, feldspar, olivine, pyroxene and amphibole.

Obsidian (Volcanic Glass)