Down to Earth Extra January 2023

The January 2023 edition of Down to Earth Extra has been published. You can dowload it from HERE or you can read it below.

Glaciers Have Been Around for 60 Million Years

THIS ARTICLE tells us that glaciers have been around for far longer than was previously thought. It was assumed that the first glaciers of the current ice-house phase appeared after the dramatic cooling which happened 34 million years ago.

But by studying glacial landforms in the Transantarctic Mountains, especially cirques or corries, the authors come to the conclusion that mountain glaciers existed there for the past 60 million years.

At the time Antarctica was covered by dense sub-tropical forests.

ONLINE COURSES FOR JANUARY & FEBRUARY

Nick Chidlaw has asked me to publicise the following courses. We are, of course, pleased to do so - it is the main reason the blog exists!

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During the lockdowns of recent years, I developed and ran a number of online courses on various geological subjects (both located in the UK as well as places abroad). The idea was to offer geological learning to those who usually attend the courses (indoor and outdoor) and field trips I offer, but who were prevented from doing so because of covid-related social restrictions. I was gratified to find so many people enrolled on these courses, and I understand they enjoyed them and gained a lot of new knowledge.  

Although we can now mix much more freely again, the winter months (particularly January and February) are usually a time when doing geological events is restricted by short days and the likelihood of poor weather. Field based events are particularly affected, but indoor events can be also, if snow or ice restricts travelling to and from venues. 

It may be that more of those who enjoy studying geology in the warmer, lighter months would be interested during January and February in doing online courses that enable them to study subjects in their own homes and in periods of time when convenient to them.  A detailed, illustrated course document  is emailed (PDF form) to each enrollee for them to download onto their pcs. These courses 'simulate' an indoor slide-based lecture course. This involves reading through the document in stages as and when convenient to each enrollee, during a set 'Reading Period' of time (scale of weeks). An optional reading list is provided, should enrollees wish to read around the subject further. At the end of the Reading Period, the simulation continues with a 1 week optional 'Dialogue Period' in which all enrollees can send to the tutor if they wish to any questions regarding the course material and which I will answer. A concluding email is then sent to all those enrolled on the course, in which questions and answers are shown that I consider the most beneficial to the learning of the group as a whole.   

I am offering to run 2 such online or 'Distance Learning' courses, one in January, and one in February of 2023. They are independent of one another - you can enrol on either, or both. Please find outline information below. Any queries, email me at nickchidlaw@gmail.com.  I hope you find these proposals interesting and decide to enrol. 

COLD DESERTS OF THE PAST 

Tutor: Dr Nick Chidlaw 

The Quaternary Period extends from 2.6 million years ago to the present, during which time the earth has experienced extensive ice sheets developing episodically in the mid-latitudes. This course focuses on 2 such occasions when glaciations developed in Britain, and looks at sedimentary deposits created in the area of the Cotswold Hills in the west of England. The first is from the 'Anglian Glaciation' over 400,000 year ago, when ice extended down the Vale of Moreton depositing glacial till and outwash gravels. The second is the 'Devensian Glaciation' (less than 100,000 years ago) when meltwater sands and gravels were laid down in the Cirencester area under a cold, tundra climate.

 Coln Gravel Pit near Fairford, Glos.  October 1995. These workings are now flooded to form a lake used for watersports.    

Reading Period  (3 weeks) Monday 2nd - Sunday 22nd January 2023. 

Dialogue Period  (1 week) Monday 23rd - Sunday 29th January 2023

Tuition Fee: £30.00 per person.  No prior knowledge of geology or the study area is assumed. The course document would be sent out to enrollees just before the Reading Period starts. 

In view of postal delivery problems, fees are most conveniently sent by bank trans. I can provide details to those enrolling. 

Course viability deadline Friday 30th December. Fees received will be reimbursed soon after if the course does not reach viability by this date.  

THE FORMER WYE GLACIER FRONT AT HEREFORD 

Tutor: Dr Nick Chidlaw 

Some 26,000 year ago, much of northern and western Britain lay below continuous glacier ice, and adjacent lands were occupied by inhospitable tundra. The Wye Valley Glacier, over 200 m thick, reached as far east as Hereford, where local hills protruded island-like above the ice sheet. This course offers an opportunity to study the legacy of this glacier, some 40 miles from Bristol created during the Devensian, the most-recent glaciation of the Quaternary period. Highlights include the plugging of the pre-glacial valley of the river causing its re-direction to that seen today, and the pond-studded 'kettle-kame moraine' deformed during the melting of contained ice.    

Hereford Pit, a few miles west of the city, in October 1996. Glacial outwash gravels. The Pit is now backfilled and re-landscaped.  

 

Reading Period    (3 weeks)  Monday 30th January - Sunday 19th February 2023. 

Dialogue Period (1 week)  Monday 20th - Sunday 26th February 2023. 

Tuition Fee: £30.00 per person.  No prior knowledge of geology or the study area is assumed. The course document would be sent out to enrollees just before the Reading Period starts. 

In view of postal delivery problems, fees are most conveniently sent by bank trans. I can provide details to those enrolling. 

 Course viability deadline Friday 27th January. Fees received will be reimbursed soon after if the course does not reach viability by this date.  

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New palaeontology online short course from the Natural History Museum

You may be interested in this course from the Natural History Museum. You can find full details HERE.

• Location: Online
  
  
• When: 16 January - 24 February 2023
  
  
• Adult: £149

• Members: £127
  
  
  

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An NHM Masterclass short course

Life on Earth has an intricate history of origins, adaptations, radiations and extinctions but with every new discovery our understanding of the evolution of life becomes clearer. Join a team of Museum researchers and curators as they highlight six moments in the 500-million-year evolutionary history of complex life on Earth, from the beginnings of animal life itself, through the greening of the planet, all the way to the evolution of modern mammals and their subsequent diversification even back to the water whence all life arose.

This course will be delivered online. Each week, a pre-recorded lecture developed specifically for this Masterclass will be released ahead of two live, moderated, interactive Q&A sessions later in the week. The Q&A sessions will be recorded for those unable to attend live, and a reception event will be held for all enrolled students in the last week of the course, for students to meet their peers and the course lecturers at the Museum.

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 Does Evolution Have Favourite Forms - YES!

A correspondent brought THIS ARTICLE to my notice, pointing out that Simon Conway Morris had written about the same thing in 2004 - see HERE. Very true but it does bear repeating. Evolution tends to give the same solution to similar problems even when it is starting from a greatly different source.

The main example the author uses is the crab. Apparently there are five different sorts of crabs alive in the world today. They all look rather similar but, although they are all decapods they are, otherwise, not related.

Crabs are not the only group discussed. The author mentions mammals. There are two major groups - marsupials (with pouches) and placentals which includes you and me. Very different biology but each group has a version of moles, mice, anteaters, gliders, cats and wolves.

Wolf skulls. The marsupial on the left and the placental on the right. The similarity is unmistakable.

The author goes on to discuss similar organs such as eyes. And speculates that alien intelligences may not look all that different from us. Neither the author or I think they are already among us!

1 Day Field Course with Nick Chidlaw

Nick wanted to run this course in early October; there were enough people who wanted to go on the course but there was difficulty with the date. So he is going to run the course on Sunday the 5th March. Nick has contacted the people who expressed an interest in the October date, but if you want to join, I am sure Nick can find a place for you. All you need to know is in Nicks advertisement which is below.

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  A CIRCULAR WALK IN SOUTH GLOUCESTERSHIRE: shallow tropical seas and rivers, ice age valley incision 

Sunday 5th March 2023   10.00 am - 5.00 pm

The generally low-lying landform of much of the county of South Gloucestershire is interrupted near the village of Cromhall by a steep sided, narrow meandering valley lined by rocky crags. The base of the valley was dammed in the 19th century to form a 700m+ long lake, part of the grounds of Tortworth Court (now a hotel). Some 40m deep, the valley is short: indistinguishable from the surrounding countryside only 2 miles to the south of the lake, and likewise so in the open ground on the lake’s north-west side. The stream that feeds and exits the lake is small, and is a ‘misfit’, occupying a valley cut by much more powerful waters during the ice age. Rock exposures, including the natural crags, track cuttings and old quarry workings provide an opportunity to examine the local character of successive stratigraphic units of the Carboniferous Limestone Supergroup. The strata dip 20 – 30 degrees to the south and south east, demonstrating the structural contrast between that found north and south of the ‘Variscan Front’ in the Bristol area, established by the end of the Carboniferous period some 300 Ma. No previous knowledge of geology or the area will be assumed.   

 

A handout outlining the day’s programme, including location sketch map, geological map and cross section, illustrated geological history and written log of the succession of strata, will be forwarded in advance of the course to those enrolled.

Note that enrollees will need to:

*     Arrange their own transport

*     Bring a packed lunch and any refreshments (e.g. flask of coffee, fruit juice, mineral water etc.)

*     Wear strong footwear with good tread and ankle support, and have waterproof clothing if weather is poor.

*     There will be no requirement to wear hard hats on this course. 

Attendees will be insured against accident for the duration of the course. 

Tuition fee: £30.00 

Contact tutor Dr Nick Chidlaw nickchidlaw@gmail.com to enrol and for any queries. 

Deadline for course viability: Friday 6th January. If the course has become viable (minimum of 10 enrolments) by this date, enrolments will be able to continue until 1 week (Sunday 26th February) before the course runs..   

Google Earth oblique image of the study area, looking south showing the abruptly-incised meandering valley and lake near the village of Cromhall. 

Track cutting in the Cromhall Sandstone Formation (Middle part). The character of the Carboniferous Limestone Supergroup changes notably between South Gloucestershire and the Mendips; in this area in the north, reddish quartz sandstones and mudrocks, deposited in rivers, occupy much of its upper part and are virtually absent in the south. 

Anyone Want an Indoor Geology Course?

The following has appeared on the Teme Valley Geological Society's mailing list. Some of you may be tempted to reply to John Nicklin at martleypfo@gmail.com

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GEOLOGY COURSES

We have previously raised the question of geology courses. Nick Chidlaw has offered a wealth of these, both in and outdoors.  For now perhaps focus on the indoor ones (although the formations are much more visible in the winter months of course). 

 Here is one--£30/person min 10 enrollees:--

PERMIAN STRATA IN NORTH EAST ENGLAND: continental dune fields, marine reefs and karstic collapse 

Indoor day 10.00 am – 5.00 pm  Martley Hall

During the Permian period (299 – 252 million years ago), the crust that became the British Isles was located just north of the equator, under a hot, dry climate. Here, continental environments characterised the period, except in parts of north, where in Mid and Late Permian times episodic marine incursions laid down mostly carbonate sediments with interbedded evaporites. In the north east of England, Permian strata of both continental and marine origin are well represented and exposed, particularly along the attractive coastline. They are impressive, reflecting a variety of environments: continental dune fields, succeeded by both deep and shallow water shelf deposits, including an extensive bryozoan reef belt 20 miles long and up to 100m high. In some of the marine strata, fish, land plants and land reptile remains are preserved. Localised as well as extensive wholesale landsliding of the marine shelf  is evident. In what are now the onshore areas, the evaporites (chiefly halite and anhydrite) were subsequently mostly dissolved, forming impressive collapse features. Bizarre concretionary structures, which may have developed in much more recent geological times, characterize some of the carbonates. 

Nick also runs a course on our local Martley geology but he felt that you would all know this too well (hands up, I don't, so maybe he assumes too much)

I know email circulations are not usually productive in assembling groups of participants, but let me know if you will. When? If numbers materialise we'll sort it out as Nick is pretty busy.

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What If the Asteroid had Missed? 

The asteroid hit at the end of the Cretaceous, killed off the dinosaurs (birds are the only survivors) and gave mammals the space to thrive. THIS ARTICLE by a Bath academic speculates on what would have happened if the asteroid strike had not happened.

Was the arrival of intelligent tool-users inevitable? And would they be dinosaur descendants. 

Probably not. Sauropod dinosaurs had a long history of being huge in body, small in brain. From the Jurassic to the end of the Cretaceous this held true.

Carnivorous dinosaurs had a similar history - big bodies, small brains.

This recipe may not have been a precursor of intelligent tool-users but it would have been enough to stop mammals (especially us) from becoming such.

Brain size versus body mass for dinosaurs, mammals, and birds. Nick Longrich

The development of mammals was not inevitable. Monkeys in South America remained as monkeys. Primates in South America never (even after at least three starts) develop large brains - they went extinct. 

Only in Africa did we emerge.

This is inevitably a very speculative article, but well worth reading.

GeoNews Autumn/Winter 2022 Edition 

The latest edition of GeoNews - the Geo Conservation Newsletter - has been published. You can get it HERE or read it below.

Down to Earth Extra December 2022

The December edition of Down to Earth Extra has been published. You can dowload it from HERE or you can read it below.

Why are There 8 Billion of Us? 

You can find one set of answers to this intriguing question HERE. And among the answers is friendliness! Compared to Neanderthals, Homo sapiens (thats us) lived in larger groups and interactions with other groups were more likely. Thus finding a mate from outside your family was more possible. Genetic deformities are less common in Homo sapiens than in Neanderthals.

(As an aside, I have been told that the invention of the bycycle was the cause of vastly improved genetic health in the nineteenth century.)

Homo sapiens may have had a slightly higher rate of reproduction; their friendliness encouraged the creation of networks which allowed the spread of technologies which got us through changes in the worlds climate. Other humanoid species were less resilient.

This is an interesting article, even if much speculation is involved. And it has the following graph which is frightening!

Based on estimates by the History Database of the Global Environment and the UN. Max Roser, CC BY-SA

Dragonflies in the Carboniferous 

A correspondent has sent me the Newsletter of the British Dragonflies Society which contains an interesting aricle about Griffinflies. You can sign up for their Newsletter near the bottom of THIS PAGE.

To save you going through the rather long newsletter I have reformatted the Griffinfly section and you can get it HERE. Or read it below.

For me the greatest interest was the discussion on the gigantism of the beast and it relationship to the higher oxygen levels of the Carboniferous. Gigantism may have more to do with the lack of predators than with oxygen levels. - Very interesting!

Fossil Lizard Found in Skye 

A correspondent has brought THIS WEB PAGE to my notice. It concerns a tiny lizard, Bellairsia gracilis, which was found on the Isle of Skye a few years ago. It is Middle Jurassic in age. 

Its importance is that it is a "stem" fossil - it split from other lizards just before other groups developed.

This article is a good, but very simplified version, of the academic article in Nature. You can find that HERE. Once again I am amazed at the detail which can be found in fossils with the use of modern instruments. As an example look at the illustration below.

WEGA Excursion to the Lake District - New Low Price!!! 

The Blencathra Centre has recently confirmed that there has been a major reduction in the cost of this excursion!!!

 - now £289!!

So if the cost was putting you off you can still get on the trip. It will run from Friday 21st to Tuesday 25th October. 

At Blencathra FSC

Course Outline - by own transport but car sharing can be arranged.

Friday 21st - travel to Blencathra Field Studies Centre. (Field Studies Council - Blencathra FSC Blencathra, Keswick CA12 4SG, UK) Introduction, meal, overnight accomodation.

The following suggestions for the trip are from the person who will be leading from the FSC James Margeson <j.margeson@field-studies- council.org>

Sat

Morning: School House Quarry (Skiddaw Slate), Mungrisdale. Access is a 100m walk from roadside parking around 20 minutes drive from the centre.

Afternoon: Glenderterra metamorphic aureole. 4km round walk on a bridleway track from the centre. ~50m ascent and descent.

Sun

A day dedicated to the Borrowdale Volcanic Group. This rock group is probably the trickiest to access in terms of walking and parking.

I’m thinking perhaps a walk from the Honister slate mine car park to the quarries on Fleetwith Pike, about 3km and 100m ascent on a vehicle access track. This is one we can discuss though as there are a few different options we could look at.

Mon

I would suggest a visit to Shap Pink Quarry and the Shap Well unconformity. Both involve very short accessible walks. This would suit participants travelling south at the end of the course.

The field locations will be a mix, reflecting the varied and distinctive geology of the Lake District.

Cost £289 per person for residential field course.

In order to confirm your participation in the event, we do need a deposit please of £100 per person, which will be collected by our treasurer Judy Hible (email : judyhible@talktalk.net)

Please advise me, as (temporary, acting) Field Secretary that you are coming on the trip.  Or please email me with any questions: Janet Hellen <jdhellen@btinternet.com> 

Marine "Dinosaurs" - Also Scary 

A correspondent has sent me THIS LINK. It concerns recent discoveries of Late Jurassic fossil mososaurs from Morocco. These grew up to 12 metres long and fed on other mososaurs. The 12 metre beastie has been given the name of Thalassotitan atrox.

Most mososaurs had small teeth, suitable for catching fish. Thalassotitan was shaped more like a killer whale. The fossil bones found with Thalasotitan indicate that it ate other mososaurs and plesiosaurs.

The presence of a top predator like Thalassotitan suggests that the ocean ecosystem was flourishing just before the asteroid which killed the dinosaurs struck.

Thalossotitan skull

What I Did on My Holidays 

Well it wasn't a holiday - it was a Geological Learning Experience in New England, led by Dave Green. It just seemed like a holiday.

I am not going into the details here, I am just going to show some photos of things which caught my geological eye.

The photos on the blog are duplicated in much greater detail elsewhere. You can see them by clicking on the photo. If you click on the photo on the photos.churchard.com page, you zoom in even further. You may need to wait for a few seconds for the larger version to come into focus.

Garnets in a rock, on a traffic island, Hague, New York. Probably from Gore Mountain.

We found some less spectacular garnets near Lake George.

Our garnets 

43 deg 29' 58.55" N, 73 deg 44' 45.73" W

We went to Vinalhaven Island, off the coast of Maine, where a local geologist showed us round. Among the things he showed us were gabbros in granite which he described as being like pillow lavas. Instead of lava flowing into cold sea water, he describes gabbroic magma at 1,200⁰C, flowing into granite magma at 600⁰C. At the moment I cannot think of another explanation.

Blocks of gabbro in a granite matrix.

Blocks of gabbro in a granite matrix. Foot scale.

Also on Vinalhaven he showed us spheroidal rhyolite which is a most peculiar rock. How it forms is, to me, a mystery.

There is a limited outcrop of this rock and the local geologist tells us that specimen collection is forbidden.

Much of our time was spent on the Maine coast which is incredibly complicated with several terranes being plastered onto the the North American Plate. But you can see some very nice rocks.

Finely bedded sediments of the Silurian - Ordovician Kittery Formation (part of the Merrimack Group) on an island in Saco Bay.

43 deg 27' 21.15" N, 70 deg 21' 40.45" W

At Bald Head we saw the same rocks in a more metamorphosed state.

At Bald Head sediments of the Kittery Formation form a syncline.

There are good examples of boudinage.

43 deg 13' 11.62" N, 70 deg 34' 37.68" W

Also we had some rather good scenery to look at. 

Basin Brook reservoir.

44 deg 16' 9.67" N, 71 deg 1' 11.90" W

And the famed New England fall colours could be seen.

Trees became more colourful as our visit progressed.

43 deg 44' 36.39" N, 73 deg 35' 0.37" W

All my photos will be going online soon and I will link to them on the blog. 

Dave Green had put an incredible amount of work into organising this trip and it showed in the fascinating geology we saw.

Nick Chidlaw Field Course 

Nick Chidlaw has asked me to publicise this Field Course he is organising in late November.

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Title:   CONTRASTS IN THE MIDDLE JURASSIC STRATA OF THE COTSWOLDS:  deposition at the margin and near-centre of a subsiding pre-North Atlantic rift basin 

Saturday 19th November  9.00 am - 4.00 pm (sunset at about 4 pm). 

During the Middle part of the Jurassic period, around 170 million years ago,  the crust that became the British Isles was located at about 45 degrees north of the equator and the global climate was much warmer than today, with very limited evidence for ice in the polar regions. The British crust formed a series of islands surrounded by shallow seas, at times only a few meters deep. The islands were well-vegetated and populated by a wide range of animals, dominated by the dinosaurs. In the shallow seas life was also highly varied and included a variety of shellfish and larger animals including marine reptiles. 

At this time, the  Atlantic Ocean had not yet opened; Africa and and South America were joined together and the North Atlantic was beginning to open between what is now north west Africa and the eastern seaboard of the United States. To the north, the crust remained joined, but was characterised by a mosaic of active rift basins in which sediment accumulated in greater quantities than intervening areas where less subsidence took place.  In the British area, many of these basins and intervening areas were present; here, rifting had been most active during the preceding Triassic, but was continuing to influence subsidence and sedimentation in the Early and Middle Jurassic. 

In the west of England and south west Midlands, one of these basins, known as the Severn Basin, was present; it was uplifted and eroded on its north west side in later geological times, so that some of its infill was removed by erosion. Its Middle Jurassic strata now form the Cotswold Hills.  The marginal faults of the rift basin are north-south orientated; those on its western side run along the east side of the Malvern Hills and Forest of Dean, and continue southwards just to the west of the Cotswolds in the Dursley - Wotton under Edge area; those on its eastern side lie along the Gloucestershire - Oxfordshire border.  

This course looks at extensive exposures in the Inferior Oolite Group of Middle Jurassic age in the Cotswolds: one near the western margin of the Severn Basin at Breakheart Quarry, near Dursley, and the other near the centre of the Basin, at Leckhampton Hill, near Cheltenham.  The Inferior Oolite Group of the Cotswolds is divided up into many rock-stratigraphic units, enabling detailed comparisons to be made between one area and another. At the two locations to be visited can be demonstrated how the strata change in thickness and type, with some of the rock units not present at the basin margins. Breakheart Quarry is to be visited first in the morning , then we travel to Leckhampton Hill for the afternoon.   

No previous knowledge of geology or the area will be assumed for those wishing to enrol on the course.   

A handout outlining the day’s programme, including location sketch map, illustrated geological history and written log of the succession of strata, will be forwarded in advance of the course to those enrolled.

Note that enrollees will need to:

*     Arrange their own transport

*     Bring a packed lunch and any refreshments (e.g. flask of coffee, fruit juice, mineral water etc.)

*     Wear strong footwear with good tread and ankle support, and have waterproof clothing if weather is poor.

*     Hard hats will be needed at the second location for this course - they will not be needed for the first. If you do not have a hard hat, I can lend you one (let  me know in advance).

Attendees will be insured against accident for the duration of the course. 

Tuition fee: £30.00 

Contact tutor Dr Nick Chidlaw nickchidlaw@gmail.com to enrol and for any queries. 

Deadline for course viability: Friday 4th November . If the course has become viable (minimum of 10 enrolments) by this date, enrolments will be able to continue until Saturday 12th November.

Breakheart Quarry, Dursley, Glos.  View showing the lower quarry and impression of the extensive nature of the workings. Here it is possible to walk across sea beds that have been bored into by marine organisms and which have the remains of oysters attached . Quarrying has long ceased; the  site is now a run by a registered charity Breakheart Community Project; it is open to the public.  

Workings in the upper part of the quarries on Leckhampton Hill, Cheltenham, Glos.  We examine this section, together with others below and above. The Hill  has many footpaths, giving full public access.

Dinosaur Footprints in the Karoo 

A correspondent sent me THIS LINK some time ago. It got lost in my inbox but thankfully it came to light today.

Dinosaur study in the Karoo of Southern Africa (Late Triassic-Early Jurassic) is hampered by the paucity of body fossils. But there are lots of trace fossils. In this study these are mainly footprints.

Over 200 footprints covering a time span of 35 million years were measured and the conclusion reached was that theropod dinosaurs increased in size by 40% over the period. 

Also there were three different types of theropod footprint, therefore three different species. But body fossils are found for only two species. 

So, in Southern Africa, fotprints tell you more about dinosaurs than body fossils. The study continues.

Natural casts of theropod tracks preserved on a cave ceiling, Tsikoane (Lesotho). Insets of dinosaur tracks from Tsikoane (top) and Roma (bottom). Figure by author/Outlines of Meganosaurus (top) and Dracovenator (bottom) are adapted from Ornitholestes (2018) and Martz (2012), respectively.

Invitation to Exhibition and Panel Discussion 

I received this invite and was asked to pass it on.

Alyson Hallett has recently completed a six month assignment; as EarthArt Fellow with Bristol university Earth science department looking at how Art and geology interact. She has a free exhibition and panel discussion on 30th September at 6pm. 

I'm delighted to invite you to my exhibition and panel discussion event at the EarthArt Gallery, University of Bristol.

It's on the 30th September, doors opening at 6, and it would be great if you could book a free ticket via the Eventbrite link below.

This follows on from my 6 month residency in the Earth Sciences Department where I've been working with scientists, rocks, volcanoes, meteorites and ideas that have rocketed me to the stars and back.

If you know of anyone else who might be interested then please pass this email and link onwards.

Very best wishes and hope to see you soon,

https://www.eventbrite.co.uk/e/impact-tickets-420153820387

Alyson

--

Dr Alyson Hallett

Poet, mentor, teacher, mystic, editor

EarthArt Fellow - University of Bristol

www.alysonhallett.com

www.thestonelibrary.com

Latest Publication: Covid/Corvid (Broken Sleep Books) co-authored with Penelope Shuttle

Tilted Ground: https://www.youtube.com/watch?v=k7x6FBb4jJI

6 Days In Iceland: https://vimeo.com/51911068: 

Study of Fossil Teeth Gives Extraordinary Details 

THIS ARTICLE shows the amount of detail which modern techniques allow. It is based on the study of a juvenile Pantolamda bathmodon, a bear-like species which became extinct in the Eocene with no living descendents. It lived about 62 million years ago, in what is now New Mexico.

An artist’s impression of the Pantolambda bathmodon. H Sharpe, Author provided.

Most of the work on this fossil was done on its teeth. The author was able to distinguish daily growth rings and to analyse the composition of each ring. He concludes that the creature was a placental animal, like us. This allows bigger babies to be born and thus larger sizes in adulthood. 

It is things like this which allowed mammals to become the dominant type of animal in the modern world.

Fossil Frogs Died from Too Much Sex 

A correspondent brought THIS ARTICLE to my attention. You might find it of some interest. Or, perhaps, not.

The existence of large numbers of frog fossils at Geisltal has been known for decades. But what was once a lignite mine and accessible, is now a huge lake and inaccessible. The fossils are now at the Martin Luther University and, recently, became available for study.

The frogs are actually toads, which have a land based life style, returning to water for reproductive activities. For modern day toads reproduction is a risky activity, especially for the females, and this is believed to be the cause of death for these fossil amphibians.

The Geisaltal lignite mine, now the Geiseltalsee

 WEGA Excursion to the Lake District

WEGA needs a few more participants to make this excursion viable. It will run from Friday 21st to Tuesday 25th October. 

At Blencathra FSC

Course Outline - by own transport but car sharing can be arranged.

Friday 21st - travel to Blencathra Field Studies Centre. (Field Studies Council - Blencathra FSC Blencathra, Keswick CA12 4SG, UK) Introduction, meal, overnight accomodation.

The following suggestions for the trip are from the person who will be leading from the FSC James Margeson <j.margeson@field-studies- council.org>

Sat

Morning: School House Quarry (Skiddaw Slate), Mungrisdale. Access is a 100m walk from roadside parking around 20 minutes drive from the centre.

Afternoon: Glenderterra metamorphic aureole. 4km round walk on a bridleway track from the centre. ~50m ascent and descent.

Sun

A day dedicated to the Borrowdale Volcanic Group. This rock group is probably the trickiest to access in terms of walking and parking.

I’m thinking perhaps a walk from the Honister slate mine car park to the quarries on Fleetwith Pike, about 3km and 100m ascent on a vehicle access track. This is one we can discuss though as there are a few different options we could look at.

Mon

I would suggest a visit to Shap Pink Quarry and the Shap Well unconformity. Both involve very short accessible walks. This would suit participants travelling south at the end of the course.

The field locations will be a mix, reflecting the varied and distinctive geology of the Lake District.

Cost £404.60 per person for residential field course.

In order to confirm your participation in the event, we do need a deposit please of £100 per person, which will be collected by our treasurer Judy Hible (email : judyhible@talktalk.net)

Please advise me, as (temporary, acting) Field Secretary that you are coming on the trip.  Or please email me with any questions: Janet Hellen <jdhellen@btinternet.com> 

Sizing a Shark - The Cosmopolitan Predator 

I came across THIS ARTICLE in The Guardian, it is based on this ACADEMIC PAPER, and concerns a study of the extinct shark Otodus megalodon. 

Sharks do not have bones, so fossils are rare. Most shark remains are teeth So to get a picture of megalodon the researchers had to create a 3D model. And the results were that megalodon was 16 metres long and weighed 70 tons. We can be pleased that it went extinct 2.6 million years ago.

The beasts teeth are found all over the (marine) world, hence its description as a cosmopolitan predator.

The authors go into speculation about the affect such creatures would have on their surrounding ecology and come to the conclusion that it would have been the apex predator, able to eat anything in the ocean, including the largest whales.

Megalodon seems to compete with Tyrannosaurus rex for the title of scariest dead beast. I do not think I would like to meet either of them.

At around 50 feet (16 metres) from nose to tail, the megalodon was longer than a bus. Photograph: JJ Giraldo/AP

1 Day Field Course with Nick Chidlaw

Nick Chidlaw has asked me to publicise this field course which he wants to run in October. All the details are below. 

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A CIRCULAR WALK IN SOUTH GLOUCESTERSHIRE: shallow tropical seas and rivers, ice age valley incision 

Sunday 2nd October 10.00 am - 5.00 pm

The generally low-lying landform of much of the county of South Gloucestershire is interrupted near the village of Cromhall by a steep sided, narrow meandering valley lined by rocky crags. The base of the valley was dammed in the 19th century to form a 700m+ long lake, part of the grounds of Tortworth Court (now a hotel). Some 40m deep, the valley is short: indistinguishable from the surrounding countryside only 2 miles to the south of the lake, and likewise so in the open ground on the lake’s north-west side. The stream that feeds and exits the lake is small, and is a ‘misfit’, occupying a valley cut by much more powerful waters during the ice age. Rock exposures, including the natural crags, track cuttings and old quarry workings provide an opportunity to examine the local character of successive stratigraphic units of the Carboniferous Limestone Supergroup. The strata dip 20 – 30 degrees to the south and south east, demonstrating the structural contrast between that found north and south of the ‘Variscan Front’ in the Bristol area, established by the end of the Carboniferous period some 300 Ma. No previous knowledge of geology or the area will be assumed.   

 

A handout outlining the day’s programme, including location sketch map, geological map and cross section, illustrated geological history and written log of the succession of strata, will be forwarded in advance of the course to those enrolled.

Note that enrollees will need to:

*     Arrange their own transport

*     Bring a packed lunch and any refreshments (e.g. flask of coffee, fruit juice, mineral water etc.)

*     Wear strong footwear with good tread and ankle support, and have waterproof clothing if weather is poor.

*     There will be no requirement to wear hard hats on this course. 

Attendees will be insured against accident for the duration of the course. 

Tuition fee: £30.00 

Contact tutor Dr Nick Chidlaw nickchidlaw@gmail.com to enrol and for any queries. 

Deadline for course viability: Saturday 10th September. If the course has become viable (minimum of 10 enrolments) by this date, enrolments will be able to continue until 1 week before the course runs (Sunday 25th September).   

Google Earth oblique image of the study area, looking south showing the abruptly-incised meandering valley and lake near the village of Cromhall. 

Track cutting in the Cromhall Sandstone Formation (Middle part). The character of the Carboniferous Limestone Supergroup changes notably between South Gloucestershire and the Mendips; in this area in the north, reddish quartz sandstones and mudrocks, deposited in rivers, occupy much of its upper part and are virtually absent in the south. 

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This looks an intriguing excursion. I would sign up for this one but will be in the USA with Dave Green on the 2nd October.