ON THE ROCKS Newsletter of the Yorkshire Branch of the Open University Geological Society March 2019

Langdale Pikes from Side Pike on Day 1 of 2018. Harrison’s Sickle is the highest peak in the centre, with the brooding crags of Pavey Ark on the right. (Peter Vallely took the photo and his report starts on page 3).

CONTENTS Rick’s Musings 1. Rick’s Musings 3. Blencathra 2018 Dear Members 7. Editor’s piece 8. 2019 AGM report Firstly, as this is the first newsletter of the year, let me say to all of you a belated 10. Baildon Hill walk 11. Committee members Happy New Year!! 12. Field trips 12. Mapping course Most of my article for this newsletter is based around a plea for your input, ideas, and opinions on a subject of great importance, and I would like as many of you to respond as possible.

This year at our AGM, Ann resigned as Branch Treasurer after a term of office probably spanning two decades. Personally, I would like to say thank you to Ann for all her hard work over the years, Ann has been a mentor to me and most certainly one of my closest friends. As a Branch we have been lucky to have Ann as treasurer for so long, and she was treasurer for at least three Branch Organisers before me.

The Yorkshire Branch of the OUGS March 2019

As a Branch we have one major problem. While we have found a temporary replacement for Ann, Jean Sampson has kindly agreed to stand in as treasurer but is only prepared to take on the role for one year, at next year’s AGM we will have to find a replacement. In addition to needing a new treasurer, next year the Branch will also need a new Branch Organiser. At the AGM in January, after eight years’ service, I gave one year’s notice of my intention to resign the position of Yorkshire Branch Organiser.

Hopefully, you will all know that for it to remain a branch within the Society each branch must have a Branch Organiser and Treasurer. There is at national level an ongoing discussion of amalgamating branches, the reason being that a reducing membership means the cost of having BO’s going to meetings is increasing per member.

I was asked at the last national committee meeting in October whether or not I would support the possibility of branches amalgamating. Personally, this is an idea that I support, but most importantly one that I support with the caveat that no branch is forced to amalgamate, and that it occurs organically. I did raise the situation at our AGM in January and the initial response from those members in attendance did not seem in favour of the idea. However, due to the low turnout at the AGM and lack of the chance of a full discussion, the decision has been deferred until the AGM in 2020. I therefore invite everyone’s opinion on the subject in the meantime.

There are two potential routes this could go down! The first is that a new Branch Organiser and treasurer are found by the Branch, at which point a vote will take place as to whether or not the Branch would like to amalgamate with another branch, which would most likely be Northumbria. The second option, if these positions were not filled, would be that the National Executive would take over and work with our existing committee. I asked the Chair of the national committee Sue Vernon for her advice and how it would work, and this was her response:

“I would just like to clarify the situation as to the term forced amalgamation. There will be no forced amalgamation, the case will be if nobody comes forward next year to stand as BO then the EC will run the Branch for a year alongside the committee. During that year discussions would take place with the committee and members as to the state of the Branch. If nobody is willing to stand as BO after that time, then unfortunately we will have to amalgamate the Branch with those close by. The Yorkshire members would be consulted as to which branch, they would switch to. If they do not respond, then we would look at postcodes and reassign accordingly. This has been the case with Oxford Branch”. Sue Vernon, Chair.

So folks, this really is down to your choice, it is up to you and you have the power to voice your opinion. Ultimately, we need you to get involved in your Branch. If you’d like to send me your opinions, please send me an email to [email protected].

Finally, my usual nag. Please keep your details up to date and if you have not paid your subs yet please send them as soon as possible.

Best wishes

Ricky Savage Yorkshire OUGS Branch Organiser (for 11 months, tick tock!)

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The Yorkshire Branch of the OUGS March 2019

Blencathra Fieldtrip 2018 – Day One

Borrowdale Volcanics in Langdale - Date: 30th October 2018

Introduction Today’s objective was to look at two contrasting environments within the Borrowdale Volcanic Group (BVG) in Langdale. The BVG forms the broad E-W band across the centre of the and contains its most dramatic scenery e.g. Rock, the Langdale Pikes and . The BVG was erupted from centres which collapsed to form calderas (notably the Caldera). These calderas were infilled mainly by volcaniclastic sediments, which we visited in the morning at Thrang Quarry. These sediments have been eroded in places to reveal the underlying pyroclastic rocks which we examined in the afternoon’s visit to Side Pike.

Tectonic Background The BVG was formed in the late Ordovician period (Caradoc stage). At the time, and Wales were part of thin continental fragment, called Avalonia, which was a bit like modern Java. During the Ordovician, the Iapetus Ocean to the north of Avalonia began to be subducted under its northern margin. The sinking plate disturbed the mantle and produced back-arc volcanism - again similar to modern Java (but with subduction to the north rather than the south). The volcanism only lasted about 5 million years probably because the spreading centre was overridden. The Iapetus Ocean eventually closed much later in the Acadian phase of the Caledonian Orogeny (Devonian) when the continents of Avalonia, Laurentia and Baltica were joined together (and England became joined to Scotland along the line of the Solway Firth/Hadrian’s Wall).

Location 1. Thrang Quarry [NY 318055] (Seathwaite Sandstone Formation) From , we walked through Chapel Stile, an odd mixture of slate tips and timeshare developments, to Thrang Quarry. Our leader, James, explained that the slates in the quarry were formed from volcanic material which was reworked and deposited in a lake after the Scafell caldera collapsed (Fig 1). Subsequently the rocks became buried and then compressed during the Acadian orogeny. This produced their strong cleavage and their low grade (chlorite) metamorphism which gives them their greenish tinge. The cleavage is roughly at right angles to the bedding, so when the rock breaks into slates along cleavage planes, we can see attractive sedimentary structures in cross-section such as cross-laminations, micro-faults and dewatering structures (Fig 2).

Fig 1. Thrang Quarry. James explains the origin of the slaty cleavage 3

The Yorkshire Branch of the OUGS March 2019

Fig 2. Close up of flame structures indicating that the sediment has been loaded slightly while still soft. The flames (which show where water escaped) point upwards

Location 2 Elterwater Quarry [NY323048] (Seathwaite Sandstone Formation) We continued to Elterwater Quarry (Figs 3 and 4) which has a convenient overlook. It is a large working quarry producing: roofing slates, ornamental tiles and aggregate. Again we saw many slates and blocks with interesting sedimentary structures.

Fig 3. View of Elterwater Quarry Fig 4. Block at Elterwater Quarry showing flaser bedding. Most of the time dark mud was deposited under quiescent conditions, but sporadic higher energy conditions produced the lighter-coloured ripple marks .

Location. 3 Side Pike [NY290052] (Side Pike Complex) We drove to the end of Langdale and then continued for another kilometre to a cattle grid at the base of Side Pike (a spur of Lingmoor ) where we had lunch. Side Pike provides easily accessible exposures of all three types of pyroclastic deposits i.e. ash fall, pyroclastic flow, and pyroclastic surge. The sequence we observed is detailed in the table below.

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The Yorkshire Branch of the OUGS March 2019

Table 1. Generalised vertical section through Side Pike Complex (adapted from Branney (2007))

James led us up the flank of Side Pike to look at a thick exposure of ignimbrite (B). Fresh samples revealed a pink matrix with abundant black fiamme in parallel orientation (Fig 5). Ignimbrites are formed when a hot suspension of particles and gas moves swiftly down the side of a volcano as a density current – this is the type of eruption that overwhelmed the Roman city of Pompeii. Ignimbrites have a matrix of volcanic ash containing gravel-sized rock fragments called lapilli. If the flow is sufficiently hot when deposited, the lapilli may weld together and flatten to form elongate shapes known as fiamme.

Fig 5. Ignimbrite showing fiamme (the dark elongated material which shows parallel alignment)

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The Yorkshire Branch of the OUGS March 2019

We climbed further up the slope and found examples of the ignimbrite layer with brecciated blocks as inclusions. It seems that water penetrated this ignimbrite while it was still hot and caused explosions which shattered parts of it into the brecciated blocks (Fig 6).

Fig 6 Ignimbrite with some brecciated sub-rectangular blocks

At the top of the ignimbrite band, we reached a grassy shelf formed by a thin layer (C) which was created by fine ash rising above the pyroclastic flow and then settling on it. This layer contained accretionary lapilli, which are formed by coalescence of hot ash (and can be easily identified as they weather into concentric circles). We continued to the next band of crags which exposed a cross-bedded tuff (D). This is interpreted as a pyroclastic surge deposit, which is low density pyroclastic flow that may have been derived from explosions as more water mixed with the hot ignimbrite. About 1.5m up this crag, there was an erosional contact with the debris flow breccia (E) (Fig. 7) which was formed by a large collapse event. Finally, we climbed to a higher crag which showed a diverse mixture of volcaniclastic and pyroclastic deposits (F) (Fig .8). It may have been produced by a combination of further pyroclastic eruptions, collapse and aqueous reworking. This was overlain by an andesite sheet (G), in which the vesicles (bubbles) had been infilled by minerals.

Fig 7. The cross-bedded tuffs are irregular overlain by a debris flow breccia (E). The boundary is at the level of the geologist’s shoulder

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The Yorkshire Branch of the OUGS March 2019

Fig 8. Diverse bed (F) – here some parallel banded tuffs (indicated by the pen) are steeply cut on their left-hand side by a flow-brecciated andesite.

Side Pike provided us with tremendous views of the Langdale Pikes throughout the afternoon (photo on front page). Perhaps it was here that inspired Wordsworth to write his immortal lines:

I wandered lonely as an ash cloud, That floats on high o'er vales and hills, When all at once I saw a flow, A host, of golden ignimbrites.

Report and all photos by Peter Vallely

References Branney M.J (2007) Side Pike. In “Geological Conservation Review Volume 17 chapter 4” (This can easily be found using google)

Editor’s piece

I hope you like what I’ve gathered together for this the first newsletter of 2019. Rick’s Musing’s this time address the rather serious and important subject of the future of our Branch. I hope many of you will take the opportunity to let him have your views on the subject.

There is a report on the AGM which rather disappointingly was attended by only nine members, a report by Peter Vallely on the first day of last autumn’s Blencathra trip, and Tony Felski recommends a gentle stroll round Baildon Hill not far from Bradford.

As Rick mentioned in the December 2018 newsletter this year’s autumn trip to the Lake District will be a mapping course and he informs me that there are still a few places left (see more details on page 12). On the subject of field trips you will see that this year the Branch field trips will be following walks from Alan Stollery’s, “The Ramblings of a Geology Enthusiast”.

As usual could I make my usual plea for any articles, photos etc that I can include in future editions of the newsletter, and also for any members still receiving a printed copy by post to consider switching to receiving it via email. This saves the Branch money and means you get to enjoy the photos in full colour.

Peter Ellenger Newsletter editor ([email protected]) 7

The Yorkshire Branch of the OUGS March 2019

Minutes of the 2019 Annual General Meeting

Yorkshire Branch of the Open University Geological Society Swarthmore Education Centre, Leeds on Saturday 26th January 2019

Present:

Rick Savage (BO), Jean Sampson, Lesley Webster, Wayne Harston, Peter Ellenger, Peter Roberts, Peter Vallely, Earl Haworth, Tony Felski

Apologies: Yvonne Ward, Arthur Speed, Philip , Beth Peart, Jim Cooper, Jane Simpkin, Roger Clayton, Paul Worral, Gill Smalley, David Leather, Ann Grosvenor, Peter Hodgkinson, Mary Johnston

The meeting was opened at 10:50 by Rick Savage who welcomed everyone to the meeting and advised those attending of Ann Goudry’s absence due to a recent stroke. All present wished Ann well and a speedy recovery.

Minutes of the last AGM:

The Minutes were taken as read, approved and signed. Proposed – Peter Roberts Seconded – Wayne Harston

Matters Arising:

There were no matters arising.

Correspondence:

Rick had received a letter from a charity requesting a donation of £500. This was politely declined.

Officers’ Reports:

Branch Organiser - Rick again expressed the difficulty of finding leaders for field trips and that for 2019 none of the previous leaders would be asked for their services. It was pointed out that all local geological societies were having this problem, but some organisations such West Yorkshire Geological Trust had members e.g. Dr Gareth Martin who were very knowledgeable and might be willing to help. Another suggestion was to use the Alan Stollery Guide for visits led by Branch members.

Branch membership is stable at 72 with three departures and one death, but four new members. This is very good considering the fall in OUGS membership in recent years.

During 2018 The Branch ran six field trips with a total of 55 members attending including three who had been on a field trip before. Sixteen people attended the Blencathra trip in November 2018, but that will be the last one as that area of the Lake District is now “worked out”. Iceland was considered as an alternative but is too expensive so a visit to Austria is being looked at:

The Newsletter editor, Peter Ellenger, continues doing a good job but needs more information from members to provide content for the newsletter. Suggestions were descriptions of members journey through the OU, interesting photographs of geological features with a small write up, walk reports, etc. 8

The Yorkshire Branch of the OUGS March 2019

Rick advised that he had been Branch Organiser since 2011 and would stand as BO for 2019 if re- elected, but this would be his final year. The role of Events Organiser needs to be undertaken by another member other than the BO. If both these roles and that of treasurer cannot be filled the Branch would need to consider amalgamation with another branch such as the North West or Northumberland. There are advantages and disadvantages and a vote will need to be taken by members. Further details are covered by Rick on page 1.

Treasurer - As mentioned above due to unfortunate circumstances Ann was not able to give the Treasurer’s report and has resigned the post of treasurer. Rick therefore gave a summary of the financial position and stated that the Branch is in balance with some £300 in the bank account.

Newsletter Editor - Peter Ellenger has been editor for nearly two years and agreed to do one more as his final year. During 2018, 21 people received the newsletter by post and the rest by email which does has an effect on Branch finances. More input and articles for the Newsletter were requested as mentioned in the BO’s report.

Election of officers:

Branch Organiser - Rick Savage: proposed by Jean Sampson, seconded by Wayne Harston Treasurer - Jean Sampson: proposed by Rick Savage, seconded by Peter Vallely Newsletter Editor - Peter Ellenger agreed to continue as editor for one more year and was proposed by Rick Savage, seconded by Peter Roberts. Event Officer - Peter Vallely proposed by Rick Savage and seconded Peter Ellenger

Alan Stollery Update:

Peter Roberts has completed indexing the 1st volume of “The Ramblings of an Amateur Geologist”. There are three more volumes to be completed. The complete works run to some 390 pages. When complete one copy will be printed and bound for presentation to Alan’s widow, Helen. Rick has said he will cover the cost of printing and binding, but members offered to contribute. It is proposed that a copy will put on the Branch’s website for access by members. It will be used for this year’s YOUGS field trips (see page 12).

Any Other Business: None.

Date of Next Meeting

Date, time and venue of the next AGM to be advised by Rick Savage.

Rick closed the meeting at 12:01, and it was followed by four very interesting talks: Coal by Tony Felski; The Lizard Peninsular by Lesley Collins; Ammonites by Michael Oates; The Geology of the Island of Westray (Orkney) by David Leather.

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The Yorkshire Branch of the OUGS March 2019

A Geological Walk Around Baildon Hill Baildon Hill is some 8km to the north of the City of Bradford. It rises 282metres above sea level and overlooks the Aire valley to the south and the Wharfe valley to the north. The Namurian Rough Rock sandstone forms the base of the hill which is then overlaid by mudstones, sandstones and coal measures of the lower Westphalian. The walk starts from Bracken Hall Community Centre (SE131390) and passes through sandstone quarries before proceeding over the top of Baildon Hill with evidence of bell pits for coal and sandstone mining and the sealed entrance of a fireclay mine.

The first exposures to be seen are of the Rough Rock Flags and Rough Rock of the Millstone Grit Group. These rocks represent the upper limit of the Namurian with the Westphalian representing a change from fluvial, river conditions to a more static, swampy environment. The Rough Rock contains some excellent examples of Carboniferous plant fossils e.g. Stigmaria and Calamites.

Stigmaria –Plant Root in the Rough Rock

Moving up Baildon Hill a 1 metre high exposure of the Listeri Marine Band is to be found. The marine band may have been affected by a small downslope movement but contains excellent examples of the bivalve Dunbarella and the goniatite Gastrioceras Listeri. Moving up and around the hill the 48 Yard Rock is crossed and old bell pits to extract the Soft Bed and Hard Bed Coals can be seen. On the way to the top of the hill the filled in entrance to a fireclay mine can be found. Good quality fireclay and ganister seat earths up to 8 metres thick can be found on Baildon Hill. The filled in adit was to a mine extracting a 1.4 metre bed of fireclay for use at a local brick and tile works. The mine must have been a significant operation as there is a stone flagged trackway leading towards the village with deep ruts worn into it by the steel tyres of cartwheels.

Four metres long Calamites in the Rough Rock Gastrioceras Listerigoniatites from the Listeri Marine Band

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The Yorkshire Branch of the OUGS March 2019

On reaching the trig point at the top of Baildon Hill there are fine views to the Dales in the north, the Pennines to the west and the Wolds and North York Moors to the east/north east. To the south west, just beyond Shipley, Noon Nick glacial meltwater channel can be seen.

The trig pints rests on the 80 Yard Rock of which very little is exposed. However, bell pits and filled in quarries at the top of Baildon Hill suggest that it was heavily extracted. In one of the few exposures Calamites fossils can be found.

Returning down the west side of Baildon Hill to Bracken Hall numerous bell pits are evident.

Bell pit into the Soft and Hard Bed Coals -above

Calamites plant fossils in the 80 Yard Rock -right

Bracken Hall Community Centre and Baildon Hill is easily accessible by car, by bus from Bradford or Shipley or by train to Saltaire and walking up through Shipley Glen or taking the Shipley Glen Tramway, if operating. Food and drink and other facilities are available at the Olde Glen Tearoom or Bracken Hall Centre (check opening times)

Report and all photos by Tony Felski

Yorkshire OUGS – Mapping in the Lake District – 19th June - 23rd June 2019

There are still a few places remining on what promises to be an interesting, informative, and fun week. Full details were given in the December 2018 newsletter, which can be accessed here, or by contacting Rick at [email protected] or by telephone on 07761 409807.

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The Yorkshire Branch of the OUGS March 2019

OUGS Yorkshire Branch 2019 field trips

This year the field trips will be following walks from Alan Stollery’s, “The Ramblings of a Geology Enthusiast”. The exact locations and dates will be advised to members shortly by Rick.

Other Branches’ 2019 field trips

Details of field trips run by other branches can be found in the latest national newsletter by logging on here

Other excursion and meeting opportunities

There are many geology trips/lectures in Yorkshire, and elsewhere, which could be of interest. Details of these can be found on the various society websites, below:

OUGS https://ougs.org/events/ LGA http://www.leedsga.org.uk/ YGS www.yorksgeolsoc.org.uk/ Down to Earth https://www.geosupplies.co.uk/ HGS www.hullgeolsoc.org.uk/ Mid-week Geology Group http://mwggyorkshire.org.uk/ Friends of Settle Carlisle Line https://www.foscl.org.uk/

Field Trip Insurance

Each person attending field meetings does so on the understanding that they attend at their 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 participants. There may be an element of appropriate cover included in Members’ own household or travel insurance. Members should also note that they will be required to take out appropriate travel insurance for any overseas events; annual travel insurance may be the best form of cover for any Member who regularly attends field events.

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