ON THE ROCKS Newsletter of the Yorkshire Branch of the Open University Geological Society December 2020
A view of Whitby looking south-east. On the clifftop is St Mary’s Church and its graveyard where Dracula used to lurk - the ruins of Whitby Abbey are behind it. The reddish sandstones towards the top of the cliff are Middle Jurassic and they overlie highly fossiliferous Lower Jurassic, which can be inspected by walking round the toe of the promontory at low-mid tide. Peter Vallely.
Editor’s piece Welcome to the latest newsletter which I hope you enjoy reading. I have tried to put together a mix of items including Peter Bratt’s visit to CONTENTS Iceland, Paul Worral’s look for fossils in Westphalian Rock in Sheffield, 1.Editor’s piece an extract from Allan Stollery’s Ramblings and a geologically-themed 2.Sue Vernon’s message poem by Beth Peart. 2.Virtual field trips 3.Þríhnúkagígur volcano On page 9 there is an important letter from the Executive committee 4.Beth’s poem regarding the future of the Branch. The Branch AGM, which you will 5.Branch AGM Agenda see from the agenda on page 5, will be held virtually via Zoom on 6.Finding fossils from the Westphalian in Sheffield Saturday 23rd January during which a discussion and vote will take 9.Important Branch Notice place on the future of Yorkshire Branch. I hope you are able to join us. 10.Rambling with Alan Please note that the closing date for registering your interest in Stollery th attending is 20 January. After the AGM there will be a virtual talk. 13.Membership renewal
Stay safe, and hopefully we’ll all be meeting up again sometime in 2021.
The Yorkshire Branch of the OUGS December 2020
Message from Branch Organiser Sue Vernon
Dear Yorkshire Members
I hope you are all well and finding things to do. All OUGS events have either been postponed or cancelled until next year a frustrating time for us all. This decision was not made lightly and considering the Governments intervention of a lockdown in England along with those of the devolved nations we feel that this was the right decision. Although we are in a lockdown situation this does not mean there is nothing going on, on the contrary many of the OUGS Branches have embraced the new technology and now putting on talks and virtual field trips via Zoom. Please check the OUGS website Events list for further information.
The virtual AGM took place as scheduled in October, and you should have received a report on the AGM via the recent Bulletin. At the recent EC meeting the decision was taken to hold AGM 2021 as a virtual meeting via Zoom on the 17 April 2021. Therefore, if you booked to go to Glasgow you should receive a full refund from the Society Treasurer.
Unfortunately, due to current situation regarding the pandemic the EC took the decision to cancel the Lancaster Symposium. The Society has a duty of care to its members and it was felt that this was the best way to guarantee their safety in the present circumstances. Symposium 2022 is now in the planning stage and we hope that by that time we will have returned to a more normal way of life.
The Branch AGM will be a virtual event via Zoom, and the agenda and registration instructions are given on page 5.
Stay safe.
Sue Vernon
Virtual field trips
You will have read in the recent OUGS bulletin that because of ongoing Covid restrictions all OUGS field trips are still postponed until further notice, and while the recent announcement of a vaccine is welcome news, it may still be some time before we’re all able to meet up again for organised trips. In the meantime there are several organisations and associations who have arranged virtual field trips, with many of them being recorded and available to watch on You Tube. And don’t forget the free courses on OpenLearn offered by the OU. The various links are:
The Geologist’s Association https://geologistsassociation.org.uk/sofageology/ British Geological Survey https://www.youtube.com/channel/UC0JCbQti3FlTIzrJGZqzh3Q Yorkshire Geological Society https://www.yorksgeolsoc.org.uk/events Manchester geological Association http://www.mangeolassoc.org.uk/onlineevents.php Cardiff University https://www.cardiff.ac.uk/earth-ocean-sciences/events Leeds Geological Association http://www.leedsga.org.uk/ The OU – free courses on OpenLearn https://www.open.edu/openlearn/free-courses/full-catalogue
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The Yorkshire Branch of the OUGS December 2020
My visit to Þríhnúkagígur Volcano Location: About 20km SE of Reykjavik, Iceland 63.998408°N, -21.698931°E Þríhnúkagígur (in English pronounced Thrihnukagigur, and translated as Three Peaks Crater) is a dormant volcano in the Bláfjöll Country Park, relatively near to Þingvellir National Park. As such it lies in a rift valley, the Reykjanes Ridge segment of the MidAtlantic Ridge, on the divergent boundary between the Eurasian Plate and the North American Plate.
Figure 1. The lava plain of Bláfjöll Country Park with the three Figure 2. Approaching the crater above the chamber craters of Thrihnukagigur in the distance.
The volcano has three craters, each just 50m or so higher than the surrounding lava plain (fig 1). The smallest, north-easterly cone is significant in that it has a small opening at top. The chamber beneath this opening was first explored in 1974 by Árni B. Stefánsson, a doctor in Reykjavík and a lifelong cave enthusiast. After years of lobbying, limited access for visitors was granted in 2012, with strict environmental conditions. The company that runs the tours tends to use the term “magma chamber” but, being so close to the surface, this is unlikely to be the case. Using the sponge analogy, this is better thought of as a space created by pooled magma before it reached the surface. Although such pools would normally cool and solidify at the end of an event, it is thought that in this case the magma “retreated” somewhat, leaving the space empty.
Figure 3. Above a 120 m deep chamber, how much do you Figure 4. Just 15m into the descent, and the cage emerges trust temporary engineering? It is worth noting that the guys from the entrance “funnel” into the chamber itself who built it also operate it
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The Yorkshire Branch of the OUGS December 2020
The chamber is about 120m deep and about 50 x 70 m at the base. Lava tubes may lead down some 200m or more. The tour starts with a 3.5km hike across the lava plain - strong boots required! (fig. 2). After receiving helmets, headlights, harnesses, etc, visitors have the treat/worry of being lowered in a cable lift (figs 3 & 4). Visitors are allowed 30 minutes at the bottom of the chamber. At the time of my visit we were not allowed to get too close to the walls or to remove any samples(!), so no closeup shots - sorry.
Dr Peter Bratt
A geological poem by Beth Peart
“Limestone-Timestone"
Land falls, dissolves and disappears Into the all-embracing sea
With long, planetary spans of time She Quietly collects the shelly souls Of her delicately fallen creatures
And makes Land
Anew
A possible addition to your Christmas present “wish list”
For my birthday early into the first lockdown my wife bought me FReNeTiC which is a word game based on the elements. It is described as “a fast-paced word race which combines skill, luck and strategy where the atomic numbers become your points”. To start the game eight tiles are placed face-up on the board in their position on the Periodic Table. Players then have 45 seconds to make as many words as they can from those tiles in the order they appear on the board. It’s an interesting variation on Scrabble and a game that everyone joins in at the same time.
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The Yorkshire Branch of the OUGS December 2020
Open University Geological Society Yorkshire Branch AGM Saturday 23rd January 2021 to be held at 10.30am
By Zoom digital meeting software
Members wishing to participate must register with the newsletter editor
by Wednesday 20th January
Agenda
1. Welcome 2. Apologies 3. Minutes of the last meeting held on 25th January 2020. These appeared in the March 2020 Newsletter. This can be seen by logging into the Members section on the YOUGS website here then continuing to the Members Information Pages 4. Matters arising from those minutes 5. Correspondence 6. Officers’ reports; Branch Organiser, Treasurer, Newsletter Editor 7. Discussion and vote on the future of the Branch 8. Election of Officers; Branch Organiser, Treasurer, Newsletter Editor (if applicable) 9. Alan Stollery update 10. Any Other Business 11. Date, time and venue of next meeting (if applicable)
Please note: for on-line voting on the future of the Branch and for election/re-election of officers (if applicable), only ONE vote can be cast per device.
Following the AGM there will be a virtual talk given by Bill Fraser who some of you may remember has led a number of YOUGS field trips in the past. The subject is Rock for Ribblehead - The rocks used in the construction of the viaduct and where they came from. This has been in the news recently because of the current maintenance work being carried out on it.
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The Yorkshire Branch of the OUGS December 2020
Looking for Fossils in Westphalian (Coal Measures) Rock The lockdown has meant the postponement or cancellation of many of the normal OU and associated Field Studies which has led to myself and others looking much closer to home for our ‘Geology Fix’.
Where I live in South West Sheffield is on Carboniferous System, the border between the Westphalian (Coal Measures) and Namurian (Gritstone) Series. The local rocks are approximately 300Ma old and comprise mainly Sandstone, Shale, Coal Seams and Seat Earth. Fossils can be found in all these sedimentary rocks although when studying walls and paths we tend to be looking at the sandstone component of the series.
Popular mythology would lead people to believe that fossils are normally found in limestone or chalk, rocks which are comprised mainly of calcium carbonate. However, close examination will show that it is easy to find fossils in more silica based sedimentary rock.
Common fossils of the Westphalian and Namurian Series (Ed. D Whiteley. The Natural History of the Sheffield Area. Sorby Natural History Society. 1985)
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The Yorkshire Branch of the OUGS December 2020
The main drainage system of South West Sheffield is the River Sheaf (fig 1.) which runs north east, parallel to the A621, from the confluence of Old Hay Brook and Totley Brook to the confluence with the River Don just north of Sheffield Station. The river is approximately seven miles long and although comparatively short it offers a rich environment for the fossil hunter.
The river’s beaches and load which consist mainly of sandstone boulders can yield an abundance of fossil tree bark, leaves and roots. The river banks are also rich in fossils, the black shale containing marine bands of goniatites which are small snails. The seatearth of the coal seams contains tree roots, the roots of the coal plants.
Figure 1. The River Sheaf Location 1. GR325818. The South West Side of Abbeydale Industrial Hamlet Pond. The path on the SW side of the Hamlet Pond consists of large sandstone flagstones (fig. 2). The sandstone flagstones also yield tree roots. Pebbles and trace fossils (worm casts and tunnels) are also often found in the local sandstones. Fig. 3 is an example of a root. Pebbles weather in a different way or have often dropped out of the country rock. Participants should also be wary of mason’s chisel marks which also scar the rock. Unfortunately, this location is behind a locked gate, however participants can view the examples with permission.
Figure 2. Calamites in the sandstone flagstones Figure 3. A tree root in the sandstone flagstones
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The Yorkshire Branch of the OUGS December 2020
Location 2. GR324817. The Path in Beauchief Gardens The path and walls of Beauchief Gardens are rich in fossils, with few people realising they are walking on 300Ma of history! A tree root and calamites (fig. 4) can clearly be seen in the path.
Location 3. GR318804. The Dry Stonewall at the Side of Middledale Road Cottages Local dry-stone walls often offer an abundance of fossils, both real and trace (fig 5).
Figure 4. A tree root and calamites in the path in Figure 5. Calamites – tree roots used as capping Beauchief Gardens stones on a dry-stone wall
A common question is, where did this rock come from? The Victorians didn’t have the means to easily carry rock a long way, consequently they tended to use local rock for building. The Sheaf Valley and Ecclesall Woods are scarred with numerous locations where rock has been removed for building and crucible making. There is also a large disused quarry on Stonecroft Road GR314802 just off the A621. The rock from this quarry was also used to build the sandstone houses and other buildings in the area.
Careful study of local sedimentary locations offers an abundance of fossils. What is there in your area? Please check paths and walls, you may be surprised at what you find!
Article and all photos by Paul M. Worrall ([email protected])
“Geology of Yorkshire” The photo of Whitby on the front page is taken from Peter Vallely’s excellent article describing the geology of Yorkshire.
In it, Peter reminds us that in Yorkshire we are very fortunate to have rocks from nearly all the geological periods between the Ordovician slates of Thornton Force waterfall (right) to the Tertiary Cleveland Dike near Goathland. He concludes by asking “Why go anywhere else?”. The article, which is accompanied by some stunning photos, is available on the Branch website here. Thornton Force near Ingleton
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The Yorkshire Branch of the OUGS December 2020
Important Branch Notice
Dear Yorkshire Branch Member
Future of the Yorkshire Branch
As you are aware, no one has come forward who wishes to be Branch Organiser for Yorkshire Branch and the Executive Committee has been overseeing the running of the branch with your committee for this last year.
In view of the difficulty you are encountering in recruiting Officers, we feel that it is no longer sustainable as a stand-alone Branch and it would be in the interests of your members and the wider Society if we either merge it with East Midlands Branch or close it and reallocated members to adjacent branches. Therefore the next AGM on 23rd January 2021 will sadly be the last AGM for Yorkshire Branch.
Should the meeting vote in favour of a merge, then the Membership Secretary will be in touch with you after the meeting to confirm the move. Should you wish to transfer to a different Branch, eg Northumbria, you should contact Janet Hiscott, the Membership Secretary, at that point and let her know. A request such as this is easy to accommodate. However, if the option of a merge is not accepted, all Branch members will be reallocated based on address, although again you will be welcome to choose your destination Branch.
In the history of the Society, there have been many changes to the branch areas, some have come and gone over the years and this will continue to happen in the future. It is always sad to see a Branch disappear but we are confident that you will continue to enjoy the full benefits of your membership by being affiliated to another Branch and we hope you will make (or possibly renew) friendships within these other Branches.
Finally, the Executive Committee would like to acknowledge the contribution that the Yorkshire Branch has made to the OUGS and its members over the past several decades with its packed programme of field trips, day trips and lectures. Our thanks go to the hardworking officers and loyal members that have made this possible. The sense of community and lifelong friendships that have been forged are testament to its success.
Yours sincerely
Pauline Kirtley Secretary, Open University Geological Society. On behalf of the Executive Committee December 2020
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Geologists Association Festival of Geology For those of you who missed last month’s virtual Festival of Geology, the GA have made available recordings of the four very different but interesting talks which ranged from the geology of the Thames Tideway Tunnel to The Day the Dinosaurs Died. The link is here.
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The Yorkshire Branch of the OUGS December 2020
Selside and Alum Pot – One of Alan Stollery’s Ramblings
Our next stop is the hamlet of Selside (SD 785 756), a few miles up the Ribble valley from Horton (see Fig 1) near the Ribblehead Viaduct. Many of the Yorkshire Dales caves are formed by streams which have managed to flow along the gently-dipping bedding planes in the limestones because the bedding planes often have impervious shale or clay linings. These streams carve out underground canyons known as streamways. Occasional potholes in the streamways allow the streams to move to lower bedding planes. If a streamway runs close to the surface, the canyon can sometimes break through the ground, allowing ordinary ramblers to follow the cave passage from above, and to enter it safely in some places. This ramble offers a good introduction for beginners to the very accessible streamways of Long Churn and Borrins Moor Cave, which are very popular with cavers.
Figure 1. Sketch map of Selside and the Alum Pot area.
If we park just before Selside and walk through the hamlet, heading up the valley, we come to a track off to the left (SW). After about 100 metres, it swings left, and there is a gate on the right, signposted to Alum Pot (note that a small fee should be paid to Selside Farm). Follow the path through the gate, and head towards a clump of trees on the hillside, which surround the spectacular pothole of Alum Pot (Fig 2). The name is probably derived from “helln” meaning “mouth to hell” rather than the chemical.
A stream will be seen to fall into Alum Pot it on the Ingleborough side, making a drop of some 200 feet or so. (I prefer feet when describing depths – they sound more impressive than metres). If you look down the chasm (with care), a bridge of fallen rock can be seen to span the hole. This is not the bottom, but some 60 feet above it. A cave runs into the pothole just above the bridge. We shall see more of this cave (Long Churn Cave) later.
Figure 2. Alum Pot
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The Yorkshire Branch of the OUGS December 2020
When you have satisfied yourself with the pothole, walk across the moor in a north-westerly direction for about fifty metres, aiming at a corner of the walled enclosure. Near the wall, you will find some cave entrances. Take great care not to confuse these entrances, because two are safe to explore, namely Upper and Lower Long Churn, and one, Diccan Pot, is definitely out of bounds. Diccan Pot (Fig 3) lies in a shallow flat rock depression near the wall. A stream flows out of the rocks on the side farthest from the wall and into a low cave on the side nearest the wall. After several metres into the low cave, the water falls down a sheer drop into the far reaches of the Alum Pot.
Figure 3. Entrance to Diccan Pot.
From the entrance to Diccan Pot, walk west towards Ingleborough, and in a matter of metres, the entrances to Long Churn will be found. There are two entrances, the one nearest the wall (or farthest from Alum Pot) is Upper Long Churn, whilst the other one is Lower Long Churn. In reality, these entrances represent where an oxbow in the cave system has collapsed, hence the entrances are both dry.
Lower Long Churn can be followed for about fifty metres. After a few metres there is a hole in the roof, and a few metres farther on, a low waterfall tumbles into the passage from the right. The wet, low cave above the fall leads into Upper Long Churn (but there are much easier ways into Upper Long Churn). The downstream passage is now carrying a stream and can be followed reasonably safely for twenty to thirty metres until the stream leaves the main passage via a low cave on the left. It is wise to turn back here, since although the cave is now “dry”, there are some deep pools and eventually large drops into Alum Pot proper.
Upper Long Churn (Fig 4), however, is an entirely different kettle of fish. It is often used to introduce first timers to caving and is classed as “easy”. It is not without some difficulties, but they are easily overcome. Wading in water has to be expected, but not more than knee deep. There are some 250 metres of relatively easy passages, providing excellent opportunities to study cave structures. There is a deep pool at the end, “Dr Bannister’s Hand Basin”, which is very near to an upper exit.
Having explored Upper Long Churn cave (or not), return to the entrance and walk across the moors in a south westerly direction, that is towards the summit of Ingleborough. Soon, a stream will be found which runs into a small rocky depression and into a cave. This is the top entrance to Upper Long Churn, and almost immediately, it slides down a chute, dropping as a waterfall into the pool we saw in the cave.
Figure 4. Upper Long Churn
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The Yorkshire Branch of the OUGS December 2020
There are a number of other caves in the vicinity, but Borrins Moor Cave in particular is well worth a visit. Many people ignore it, but it is the easiest to explore in the region. The cave is on desolate moorland and can be easily missed. The best way is to follow the stream entering Upper Long Churn upstream for about a hundred metres, then cut left across the moor for about another hundred metres. If you meet a second stream, which will be the one flowing straight into Alum Pot, you have walked too far, and will need to scour the moor. Look for depressions like large shakeholes.
The hardest part of the cave is getting into it. The entrance is large, but there is a large boulder blocking the way, and this has to be scrambled over. It is not difficult but tends to be a bit fiddly. Once over, the next fifty metres is easy walking, and provides good examples of cave features. The easy walk ends where one is confronted by a wall of rock, and it is obvious that further progress means crawling. Do not bother to try to follow the way forward but have a look back at the right-hand wall (looking into the cave), and you should see another cave branching off. A little care is needed in negotiating some boulders jammed in a cleft in the floor, but in a matter of metres, one enters into a long, almost straight, passage over two metres high. This can be followed very easily, on and on and on, until one becomes fed up of it! I carried on until my hard hat began to keep hitting the roof, and decided the cave was gradually becoming lower, and I would soon have to start stooping. I believe it continues much further, but eventually becomes a crawl.
Enough of the caves, retrace your steps to Selside, and let us consider what happens to the streams. We have a stream entering Long Churn, coming to daylight briefly, and then falling down Diccan Pot into the far reaches of Alum Pot. Another small one forms a cave near the main Long Churn openings, this cave being Simpson’s Cave, and a stream flowing from the moors drops straight into Alum Pot. The next time these streams see daylight, is in a rocky pool named Footnaws Hole (the name being derived from “foot and arse”), which is situated between Selside and the river Ribble. The pool can be found by taking a track from Selside which passes under the railway and ends in a field near “Crooked Dike Barn”. A field then has to be crossed (SD 791 753).
It is obvious that at one time the water flowed out from here into the Ribble, but the last ice age blocked this exit, so now the underground stream from Alum Pot flows beneath the river to emerge at a pool on the opposite bank named Turn Dub. The water emerging from Turn Dub flows for a few metres before joining the river Ribble. Turn Dub lies between the river and a tarn in which there is a small island. It is not easy to reach from this side of the river, so make your way back to your car.
Taken from The Ramblings of a Geology Enthusiast in Yorkshire by Alan Stollery and edited by Peter Vallely (Editor’s note: Alan was an active and enthusiastic member of Yorkshire Branch and his collection of walks are in the process of being collated into a single volume which will then be made available to OUGS members).
White Sands National Park in New Mexico, USA This photo appeared on my computer after I woke it up from “sleep” mode and I thought members might be interested to see it.
These rolling dunes in southern New Mexico aren’t ordinary waves of snow or sand – they’re made of gypsum. It covers 275 square miles of desert to create the world's largest gypsum dune field. As gypsum is water-soluble it would normally dissolve in rainwater and wash away. But White Sands has no outlet to a river or coast, so what little precipitation falls here dissolves the mineral, then evaporates. What's left over is selenite, a crystallised form of gypsum.
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The Yorkshire Branch of the OUGS December 2020
Renewal of Membership subscription As was mentioned in the recent Bulletin from Stuart Swales your subscription to renew your membership is due on 1st January 2021. Rates are unchanged. If you have not already set up a standing order, you can still pay via the bank with a one-off transfer. The Society’s bank details are on the renewal form which can be found in the members section of the OUGS website https://ougs.org/members/.
Otherwise, you will need to send a cheque to: Janet Hiscott, Membership Secretary, 7 Blossom Close, Langstone, Newport NP18 2LT. To save you having to remember to do this every year, why not set up a standing order for next and all future years? You will find a form with the Society bank details on the website at https://ougs.org/files/ouc/general/Membership_Renewal_2021.pdf. Please note that whilst all our forms are available on the website, they must either be printed off and posted to Janet or saved on your PC and then emailed. The OUGS does not save information of this nature on the website.
And finally……..Christmas greetings to all our readers
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