Thursday, 9 September 2021

Underwater Glacial Geomorphology

Underwater Glacial Geomorphology 

A correspondent spotted THIS on the BBC website and passed it on to me.

It concerns sub-glacial landforms which were made under ancient ice sheets. These were where the North Sea is now and have only recently been discovered using seismic survey techniques. Deep seismic techniques are used to find possible oil bearing structures, these shallow ones were originally developed to find suitable foundations for oil industry infrastructure,

The structures may give us a picture of what is happening beneath Greenland's ice cap as it melts under today's conditions of global warming.

How the Moon Made Life on Earth Possible

How the Moon Made Life on Earth Possible

A  correspondent brought two links to my notice. THE FIRST is the scientific paper on which THE SECOND (a YouTube Video) is based. If you are anything like me you will find the video much more approachable.

The thesis is multi staged. 
  • The moon slows down the rotation of the Earth.
  • Oxygen producing cyanobacteria rise to the sea surface during daylight.
  • Anaerobic bacteria rise to the sea surface at night.
  • Cyanobacteria rise slowly.
  • When day length is short cyanobacteria are not in daylight for long.
  • Longer days mean more oxygen produced.
  • Oxygen in the atmosphere allows multicellular life to develop.
You can read all about it in the Nature paper, or you can watch the video. Also in the video you have the chance to buy a T shirt!!!

You can read about the sinkholes which feature in the previous links HERE.

A term used in both paper and video is "diel". It is one I had not come across before. It is usually phrased as diel vertical migration, and Wikipedia defines it as:- 

Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The migration occurs when organisms move up to the uppermost layer of the sea at night and return to the bottom of the daylight zone of the oceans or to the dense, bottom layer of lakes during the day. The word diel comes from the Latin dies day, and means a 24-hour period. In terms of biomass, it is the greatest migration in the world. It is not restricted to any one taxon as examples are known from crustaceans (copepods), molluscs (squid), and ray-finned fishes (trout). Various stimuli are responsible for this phenomenon, the most prominent being response to changes in light intensity, though evidence suggests that biological clocks are an underlying stimulus as well. The phenomenon may arise for a number of reasons, though it is most typically to access food and avoid predators. While this mass migration is generally nocturnal, with the animals ascending from the depths at nightfall and descending at sunrise, the timing can be altered in response to the different cues and stimuli that trigger it. Some unusual events impact vertical migration: DVM is absent during the midnight sun in Arctic regions and vertical migration can occur suddenly during a solar eclipse.

Saturday, 4 September 2021

Dave Green's Programme for 2021 - 22

Dave Green's Programme for 2021 - 22 

Dave Green has produced a programme for the next year which is bursting with geological goodness!. I have put down my name for the trip to the Eastern Pyrenees next February already!

You can download the programme HERE.

Or read it below. 

Friday, 3 September 2021

Down to Earth Extra - September 2021

  Down to Earth Extra - September 2021 
The latest edition of Down to Earth Extra is HERE.

And you can read it below.

Sunday, 29 August 2021

A Podcast About the Ediacaran

A Podcast About the Ediacaran 

I came across this podcast and thought it might be of interest. You can listen to it HERE.

It tells about the finding of the fossils and the geologist, Reg Spriggs, who found them. Also the campaign to get the area declared a Conservation Park.

Saturday, 28 August 2021

The Ancestor of All Scaled Reptiles

The Ancestor of All Scaled Reptiles 

THIS ARTICLE tells us of a very well preserved, but tiny (32mm), fossil found in north west Argentina in 231 million year old (Late Triassic) sediments. It is described as the most primitive scaled reptile yet found.

It is a Lepidosaur - a group which contains lizards and snakes - the most diverse group of terrestrial vertebrates presently alive. But very little is known of their early origins. I has been named Taytalura alcoberi.

The enormous reptiles of the period are well known. In contrast, the little ones are almost unknown. It is hoped that this specimen will lead to the areas of ignorance being diminished.

If you have access you can read the original paper HERE.

Life restoration of the Taytalura skull. (Jorge Blanco, Gabriela Sobral and Ricardo Martínez).

Police Raid Finds Flying Reptile Fossil

Police Raid Finds Flying Reptile Fossil 

Yet another correspondent directed me to THIS ARTICLE. It tells us that a police raid in São Paulo found six limestone slabs with a very well preserved fossil of Tupandactylus navigans, a member of the Tapejarid subgroup of the pterosaurs

You can find a much larger version of this HERE

Tupandactylus navigans fossils are commonly found in Brazil but usually only the head is preserved. This is the most complete tapejarid skeleton ever found in Brazil.

I wish I knew more of how the police raid happened and did the "owners" know what they had.

The scientific description of the specimen can be found HERE.

All You Need to Know About Dog Vomit Slime Mould

All You Need to Know About Dog Vomit Slime Mould 

A correspondent brought THIS ARTICLE to my notice. As she said it is not very geological - slime moulds (actually myxomycetes) have a limited place in the fossil record - but it is a fascinating read. 

If you want to know about a single cell that can grow as large as a bath mat, has no brain, no sense of sight or smell, but can solve mazes, learn patterns, keep time, and pass down the wisdom of generations, read the article!

The slime mould is used by the author to talk about the classification of nature and the creation of hierarchies. All in all a very good read.

Badhamia utricularis

Four-Legged Egyptian Whale

Four-Legged Egyptian Whale 

Two correspondents directed me to this fossil find made in the Fayum Depression in Egypt. The beastie lived 43 million years ago and marks the transition from, as Darwin said, "something like a bear" to modern whales.

You can read all about it HERE and HERE.

An imagined reconstruction of Phiomicetus anubis by palentologist Dr Robert Boessenecker

(Robert Boessenecker)

Wednesday, 25 August 2021

The Five Most Impressive Geological Structures in the Solar System

The Five Most Impressive Geological Structures in the Solar System 

Or - Field trips I would like to go on.

I came across THIS ARTICLE and, although it has little to do with the West Country, could not resist putting it into the blog.

My favourites are the fold mountains of Venus and the drowned coastline of Titan. 

Fold mountains in Ovda Regio, Venus. The insert is a similar view of part of the Applachians in central Pennsylvania. NASA/JPL

Left: Part of Titan’s Ligeia Mare, showing a coastline with valleys drowned by a sea of liquid methane. Right: The Musandam peninsula, Arabia, where coastal valleys are similarly drowned, but by a saltwater sea. NASA/JPL-Caltech/ASI/Cornell and Expedition 63, International Space Station (ISS)

Thursday, 19 August 2021

Mars in 4K Resolution

Mars in 4K Resolution 

Various sources have brought this video to my attention. The pictures are amazing  (Very Good). So is the commentary (Words good, Voice awful).

You can see it HERE, or watch it below.

Bath Walking Trails

Bath Walking Trails 

A correspondent from Bath Royal Literary and Scientific Institution has sent me some information on four walks around Bath, some of which will be of interest to geologists. They are all of interest to everyone!

She Writes:-
I wonder if you would be interesting in circulating the information below about the new BRLSI Bath Discovery Trails, accessed with a free App for Android and Apple Smartphones, produced in collaboration with BathSpa University? I think some of these will interest your readers.

The four walking trails are: The First Meteorite, The Railway Leviathan, On the Origin of Species and The War Crosses.

All you need is your phone and a decent pair of shoes; the trails take about 1.5 - 2 hours to walk, but you can easily skip sections or take a break along the way if you feel the need! Bath Royal Literary & Scientific Institution is open 10-4, Monday to Saturday.

The First Meteorite

This centres on an object from outer space that is small enough to fit in your hand and is 4.2 billion years old. This trail explores ‘deep time’ and the very origins of our solar system through a story that connects 18th-century astronomers with druid temples and a Siberian forest. Once you have completed your journey to BRLSI you will be able to see this unique fragment from the earliest years of the universe.

Activation Code: bathdiscovery3

The Railway Leviathan

Rediscover a lost world, here in Bath. This trail brings to life extinct species from a time before human beings and explains how the industrialisation of Bath’s landscape in the nineteenth century unearthed long lost creatures that once roamed the land and swam in the seas where Bath now stands—and how BRLSI was crucial in preserving that prehistoric past. At the end of this trail you will be able to view the skull of a Jurassic steneosaurus, just one of BRLSI’s many fossils.

Activation Code: bathdiscovery4

The Origin of Species

Learn about one of the world’s most important scientific books through the lens of a very local friendship. Charles Darwin spent his life gathering data based on his observations of animals and plants, which would lead to the development of the theory of evolution. This trail explores the lifelong friendship between Darwin and Leonard Jenyns, who lived here in Bath, through a correspondence that reveals a shared love for natural history and intellectual curiosity about the natural world. Jenyns donated his library to BRLSI and, once you have completed the trail, you will be able to see his own copy of Darwin’s On the Origin of Species, alongside a letter he wrote to Darwin.

Activation Code: bathdiscovery2

The War Crosses

Take a closer look at the human cost of conflict through the city’s war memorials and the soldiers who experienced this first industrialised war. In this trail you will discover the places where returning soldiers were treated for their injuries, the houses where army generals lived, and the memorials to the fallen. Once you complete the trail you will be able to view relics of the Crimean War, part of BRLSI’s extensive collections related to human conflict across the centuries.

Activation Code: bathdiscovery1

You can download the app for free via your usual provider or just click on the links:


Saturday, 14 August 2021

Join the Avon RIGS Group

Join the Avon RIGS Group 

As the threat of Covid seems to be in retreat, the prospect of field work advances.

And an opportunity for field work is with the local RIGS group. RIGS (regionally Important Geological Sites) is administered by BRERC (Bristol Regional Environmental Recording Centre) which is based at Blaise Castle House Museum. 

A look at BRERC's web site (see HERE) shows it is mainly concerned with wildlife but it is trying to enliven its geological footprint. There are many RIGS in this area and many have not been looked at in decades. Joining the RIGS group will help get the data base up to date. 

The tasks can range from the easy - does the site still exist?, is it overgrown, has it been built on, is it accessible - to the more exacting - what are its exact boundaries, does it show what it is said to show.

The first step to help with this endeavour is to join the Group. To do so send an email to Tim Corner at asking to join.

Friday, 13 August 2021

Does Global Warming Lead to Mass Extinction?

Does Global Warming Lead to Mass Extinction? 

We know when mass extinctions have happened; we know the sea surface temperature for many millions of years. Is there a connection?

THIS ARTICLE, based on THIS PAPER, looks at this. And the news is not good!

Data for the two sets is usually not presented in similar ways. Extinction data usually comes as number of disappearances per geological stage; sea surface temperature is more nearly continuous.

To make correlations the authors put the data into 10 million year time bins and this is what you see below.

Changes since the end of the Ordovician: red = extinction rate in time bins; green = the greatest magnitude of change in temperature in each bin; blue- the greatest rate of temperature change in each bin. Grey bars show mass extinctions (Credit: Song et al., Fig 1)

The data shows that there is a good correlation between the two data sets. When the sea surface temperature rises quickly, mass extinctions happen. 

And the sea surface temperature is rising very fast indeeed.

Monday, 9 August 2021

Jurassic Ark – Spectacular Fossils from an Ancient Somerset Sea

 Jurassic Ark – Spectacular Fossils from an Ancient Somerset Sea

A Summer Exhibition, with free entry, at the Bath Royal Literary & Scientific Institution (BRLSI), 16 Queen Square, Bath BA1 2HN, until 2nd October, 10am–4pm Monday–Saturday.

The Bath Royal Literary and Scientific Institution is celebrating their unique collection of fossils from the Lower Jurassic of Strawberry Bank. Beneath the Somerset town of Ilminster, lies a beautifully-preserved Jurassic ecosystem, from which Victorian geologist Charles Moore collected hundreds of fossils. The fossils show exceptional preservation, revealing soft tissues such as muscles, guts, and traces of skin. Importantly, they retain the animals’ original three-dimensional shape. Uncompressed, three-dimensional fossils that preserve soft tissues are very rare, and the concentration of a diverse fauna at this site makes it one of the best-preserved Lower Jurassic marine ecosystems in the world.

Specially commissioned illustrations by John Sibbick, one of the world's foremost palaeontological illustrators, recreate the landscape in which these extinct marine reptiles, fish, crustaceans, squid-like cephalopods, and insects flourished.

Although Moore’s original quarry was infilled in 1860, a new excavation in 2019, headed by the BRLSI, opened two trenches to study the strata of what is now called the ‘Strawberry Bank Lagerstätte’.

These extraordinary fossils have been studied in depth as part of a four-year project of intensive research through the JESBI project, an exciting collaboration between the BRLSI Collections team and Bristol University, funded by the Esmée Fairbairn Foundation. Professor Mike Benton of the University of Bristol is excited to see the findings of the project presented to a wider audience. He said “The fossils may be old, and they were collected 170 years ago, but they are providing remarkable new scientific information.”


An introduction to the exhibition can be seen HERE.

A video of the making of the exhibition can be seen HERE.

A short film about the research done on a Strawberry Bank ichthyosaur skull from the exhibition, in collaboration with the University of Bristol can be found HERE.

A series of three talks connected to the Strawberry Bank fossils which can be viewed on the BRLSI YouTube channel.

The suggested order of viewing is:-

Saturday, 7 August 2021

Down to Earth Extra - August 2021

 Down to Earth Extra - August 2021 

The latest edition of Down to Earth Extra is HERE.

And you can read it below.

Sea Level Changes Affect Eruptions

Sea Level Changes Affect Eruptions 

Many thanks to a correspondent who brought THIS ARTICLE to my attention. It is based on THIS ARTICLE in Nature.

It is based on a study of Santorini which looked at sea level and eruptions. The data covers the last 360 thousand years. In that period there were 211 eruptions, 208 occurred when sea level was low.

The theory is that when sea level is high (as it is now) the pressure on the magma chamber (4km down) keeps the roof intact. When sea level drops by 40m the pressure on the magma chamber roof lessens, cracks develop, magma, in the form of dykes, moves upwards. At a sea level drop of 70m the dykes reach the surface. 

The study suggests that it takes 13,000 years for the cracks to reach the surface. The eruption which may have been the demise of the Minoan Civilization occurred in 1,600BCE, the sea level was last below -40m 11,000 years ago, so we are in a quiet period as sea level continues to rise.

Friday, 6 August 2021

How Old Are Sponges?- Continued

How Old Are Sponges?- Continued 

Last weeks POST on sponges was the subject of a NATURE PODCAST. You can listen to it on the link.

Sunday, 1 August 2021

Seatown Landslide

Seatown Landslide 

I came across this on Facebook and thought you might find it interesting. The original post on Facebook is HERE.

Saturday, 31 July 2021

How Old are Sponges?

How Old are Sponges? 

A correspondent sent me the link for THIS ARTICLE - many thanks. It is based on THIS ARTICLE in Nature. 

The researcher, working on 890 million year old reef rocks, found structure in some of her thin sections which looked rather like those found in more modern rocks. She did this 10 years ago. In the intervening period there have been many publications which have identified similar structures as being sponges.

But her rocks were more than 400 million years older than the oldest confirmed sponge. And the oxygen content of sea and atmosphere was rather different. But she argues that the cyanobacteria, that made the reefs she was working on, were close enough to her sponges to provide enough oxygen.

So, perhaps sponges are the oldest animals and were around for a lot longer than we thought.

ABOVE: A low-magnification view of the connected network of tunnels that form a putative sponge protein skeleton fossil found in an 890-million-year-old rock. The field of view is about 9 millimeters.


The Earth's Inner Core

The Earth's Inner Core 

I came across THIS ARTICLE and now know more about the inner core than I did before - and some of it is very surprising!

The inner core is solid but is very hot and under great pressure. Previously it was even hotter and was liquid. When did the temperature drop low enough to allow solid iron to appear? Between 500 and 1,500 million years ago. People discovered its existence in 1936.

Its radius increases by 1mm per year. This implies 8,000 tonnes of iron solidify every second! Eventually all the core will solidify and the Earth will not have a magnetic field.

The inner core is lop-sided. The eastern part, under Indonesia, is growing faster than the western part, under Brazil. But, thankfully, gravitational forces sort things out and the core remains spherical.

The article tells us how all this is surmised - none of this can be found first hand! Read the page - there is lots of good stuff therein.

Seismic waves have suggested Earth’s solid iron core is asymmetrical. Sanne Cottaar, Author provided

Saturday, 24 July 2021

A "Jurassic Pompeii" - Somewhere in the Cotswolds

A "Jurassic Pompeii" - Somewhere in the Cotswolds 

Many of you must have seen THIS WEB PAGE from the BBC. A correspondent brought it to my attention - Thank You!

At first glance the article looks like a very superficial piece of work, but it isn't. There is a lot of information about the geology, the palaeontology, the sedimentology and the excitement of scientific discovery. Read all the page - it goes on for a long way - look at the photos, play the videos. It is a good example of making geology interesting.

At the moment the location is secret. No doubt, some of you can work out where it is. I look forward to seeing the specimens in the Natural History Museum.

Frozen in time: Fossilised seafloor animals from the Jurassic, all piled on top of each other

Seismology of Mars

Seismology of Mars 

A few years a go WEGA had a lecture from a Bristol University lecturer on this subject. He was somewhat limited as the only seismometer on Mars was ON a lander which had a very effective suspension. He thought that you would need an earthquake marsquake above 8 on the Richter scale to be recorded! So a lot of his talk was about the next seismometer on Mars. 

And that seismometer is the subject of THIS ARTICLE by two researchers at Bristol. 

The seismometer has detected hundreds of quakes and the conclusion is that Mars has a much larger core than previously thought. Because it is larger it must have a larger proportion of lighter elements than Earths core. And such a composition would not have an inner solid core - and hence no magnetic field.

The crust of Mars has been estimated from the quakes as 24 to 72km thick and the lithosphere 400 to 600km.

Shear waves travel from a marsquake and reflect off the iron-nickel core. Chris Bickel/Science

Tuesday, 20 July 2021

Even More Iceland Volcano Videos

Even More Iceland Volcano Videos 

John Nicklin of the Teme Valley Geological Society has, among other things, sent me A LINK to three very good drone videos. Three different styles but all good. They are all on YouTube so I can embed them below.

Monday, 19 July 2021

Stonechat July 2021

Stonechat July 2021 

I have been sent a link to "Stonechat" the magazine of the Horsham Geological Field Club. It is well worth reading, especially the article on Rock Bands! You can get it HERE, or read it below.

Saturday, 17 July 2021

Fossils Are Found in the Most Unexpected Places!

Fossils Are Found in the Most Unexpected Places! 

A correspondent brought THIS ARTICLE to my notice - Thank You! It discusses THIS ACADEMIC PAPER.

The Barberton Greenstone Belt in South Africa is very old - 3.42 billion years old. The rock discussed is interpreted as a subseafloor hydrothermal vein.

3.42-billion-year-old chert veins (dark gray) in rocks at the Barberton Greenstone Belt in South Africa

The researchers found (using sophisticated microscopes and other instruments) that they were looking at filamentous cellular colonies. Because they were in rocks which originated deep below the sea floor, they obtained their energy from chemical processes and probably generated methane.

Down to Earth Extra - July 2021

Down to Earth Extra - July 2021  

The latest edition of Down to Earth Extra is HERE.

And you can read it below.

Saturday, 26 June 2021

Venusian Tectonics

Venusian Tectonics 

We know remarkably little about Venus - the second rock from the sun - but THIS ARTICLE summarizes what we do know and goes on to talk about the planets tectonics.

Radar images give us our best picture of the planets surface. There is little erosion but also very few impact craters. This has led to speculation that the planet gets a new "carpet" every few hundred million years. If we presume Venus's composition is similar to that of the Earth, there must be a build up of heat in the planets interior. The Earth gets rid of it by means of plate tectonics, but Venus does not - the heat is got rid of by means of a vast volcanic episode which resurfaces the planet.

Polygonal blocks or ‘campuses’ on the lowland surface of Venus. Note the zones of ridges that roughly parallel ‘campus’ margins. Credit: Paul K. Byrne, North Carolina
 State University and Sean C. Solomon, Lamont-Doherty Earth Observatory

The article, while not contradicting the mega volcanic story, suggests another means of Venus losing heat. This is the jostling of what they call campuses on the surface of the planet. There is no lithosphere formation or destruction but implies mantle convection.

Hopefully the lack of evidence will be cured by the recently announced missions to Venus.

Saturday, 19 June 2021

Huge Diamond Discovered - But Not By Me!

Huge Diamond Discovered - But Not By Me! 

A correspondent brought this to my attention. It is from The Mineralogical Record but I could not find an online source, so I have copied some of what he sent me.

The Debswana mining company in Botswana recently announced the discovery of a huge diamond that they believe ranks as the third-largest gem-quality diamond crystal ever found—the two larger ones being the Cullinan (3,106 carats, found in 1905) and the Lesedi La Rona diamond, 2,109 carats, found in 2015). The new, as-yet unnamed diamond weighs 1,098 carats (7¾ ounces) and measures 7.3 cm (2.9 inches) × 2.7 × 5.2 cm. If you had this crystal in your collection and wanted to compete with it at the Tucson Show, it might be a bit too large for the “miniature” category (maximum 2 inches), so you would have to enter it in the “small cabinet” category!
The crystal was found at the Jwaneng mine, located about 75 miles from the capitol city of Gaborone and operated jointly by the Botswana Government and the De Beers Group. Officially opened in 1982, the mine typically yields between 12.5 million and 15 million carats of diamonds a year. This month's find is the largest gem unearthed by the company since diamonds were first discovered in Botswana in 1967. Whether the new diamond will be sold through De Beers channels or through the state-owned Okavango Diamond Company has yet to be decided, so you still have a chance to acquire it for your collection. But you’ll need deep pockets; the Lesedi La Rona diamond sold for $15 million.

The diamond is sub-rounded. Presumably on its journey up the kimberlite pipe the corners got knocked off. 

I once found the diamond from my wife's ring on the kitchen floor, but it was a bit smaller than this one.

Coal's Future - Hydrogen Storage?

Coal's Future - Hydrogen Storage? 

I came across THIS ARTICLE and found it interesting for a couple of reasons. 

Recent research shows that coal can store gases and the amount absorbed increases with pressure - 600kg per ton of fractured coal. The suggestion is that old coal mines could act as batteries storing hydrogen produced from sources such as wind power. 

I suspect the engineering required for this to happen is some distance in the future, but it is a nice thought.

The other reason this article was of interest was the graph showing the historical contribution of various energy sources. The implications for the future are rather frightening.

Growth in energy supply from different sources since 1800 CE (Credit:

Thursday, 10 June 2021

How Geology Affects Politics

How Geology Affects Politics 

I came across THIS on Twitter.

In the election results, blue is Democrat, red is Republican. (This counterintuitive for us Brits.)

The fertile soil was good for cotton, - and hence, lots of slaves.

Tuesday, 8 June 2021

Congo Canyon Turbidity Current

Congo Canyon Turbidity Current 

I suspect many of you have seen this on the BBC website, but HERE it is for the rest of us. The turbidity current current occurred on the 14th January 2020 and swept 1,100km into the Atlantic breaking a couple of submarine cables.

The event occurred a couple of weeks after a 50 year flood on the Congo river. This dumped a vast amount of material at the canyon head. There is speculation about why there was a pause between the flood and the turbidity current. The avalanche started at low tide, when the pore pressure inside the sediment is at its highest.

The Congo Canyon has many instruments along its length so the speed of the current could be measured.

Saturday, 5 June 2021

The Scablands

The Scablands 

A correspondent brought THIS VIDEO to my attention and it interested me for two reasons. The first is that it is about the Ice Age Floods of the Scablands in Central Washington which I visited on a WEGA excursion led by Doug Robinson in May 2016. We stayed in Ellensburg which is the home of Central Washington University with which the speaker is affiliated.

The second is that it is a journey back in time. He speaks in front of a blackboard with chalk! It brings me back to the days of my youth.

I haven't watched all of the video yet but the guy seems to know what he is talking about. I'm looking forward to seeing the rest.

Friday, 4 June 2021

Geologic Map of the World - Online

Geologic Map of the World - Online 

I came across THIS WEB PAGE and thought you might find it interesting. You can zoom in and a lot of the sea bed has also been mapped

The UK

And you can get fairly detailed views.


There is a vast store of knowledge incorporated and sometimes you can get references to look up when you click on a spot. Happy exploring!

Wednesday, 2 June 2021

Down to Earth Extra - June 2021

Down to Earth Extra - June 2021 

The latest edition of Down to Earth Extra is HERE.

And you can read it below.

Saturday, 29 May 2021

Mantle Plumes - Its Not That simple!

Mantle Plumes - Its Not That simple! 

I came across THIS ARTICLE and it looks like one I should read. But I suspect it will take me a long time! So rather than take forever to understand it and try to summarise it, I will let you do that! Best of luck! 

a | Schematic cross section through Earth’s interior, depicting the key components of plume generation and upwelling near, above and along the edges of a large low-shear-velocity province (LLSVP) and near the core–mantle boundary. These LLSVPs might contain localized ultra-low velocity zones (ULVZs) and along their edges subducted material may pile up over hundreds of millions of years. b | Schematic cross section of a plume root showing the entrainment of subducted materials, LLSVP and ULVZ components, and possibly core materials at the edge of a LLSVP and centred above an ULVZ (that might be a unique deep mantle locality containing partial melt).

Life - It Gets Everywhere!

Life - It Gets Everywhere! 

A correspondent brought THIS ARTICLE to my attention. It concerns the fact that life is found in the most unexpected places. Places where there is no apparent energy source. Places mentioned are deep underground in mines and in abyssal sediments.

To cut a (VERY) long story short the energy source is hydrogen. And this is derived from the breakdown of water by radioactivity - electrolysis without electrodes.

Bacteria found deep within a gold mine in South Africa that subsist on hydrogen and sulfate. 

G. Wanger & G. Southam

The article goes into some detail about how this was discovered and proved to be a viable energy source. - well worth reading.

Book Review - The Greywacke

Book Review - The Greywacke 

Recently I bought "The Greywacke" (ISBN 978 1 78816 377 4, eISBN 978 1 78283 626 1) written by Nick Davidson, an amateur geologist. And it is rather good!

It tells the story of how two friends, Sedgwick and Murchison, mapped the geology of Wales and the Welsh Borderland, disagreed, compromised and then disagreed completely. Later Charles Lapworth proved them both wrong. 

It does not sound a riveting read but the people involved are compelling characters and they all did remarkable work.

Sedgwick was geology professor (with a divinity and mathematics degree) at Cambridge and worked on the Cambrian. He was good but slow and full of doubts. Murchison was a retired army officer and worked on the Silurian. He was fast and did not have a doubt in his life - certainly not about his abilities! He published quickly and extensively and could not help himself encroaching on Sedgwick's territory.

While still cooperating, Sedgwick and Murchison sorted out the rocks between the Silurian and the Carboniferous and called it the Devonian, rubbishing De la Beche on the way.

Murchison, having, to his own satisfaction, coloured most of Wales Silurian, moved on to do the same to the Southern Uplands and most of the Northern Highlands. 

Also he was invited to tour Russia - twice - named the Permian and co-wrote a two volume book "The Geology of Russia in Europe and the Ural Mountains". Murchison's volume weighed in at 13 pounds! It stretched from Primary rocks in the west to Permian and higher in the east - an undisturbed sequence. Strangely, Murchison could not find any Cambrian!

By this time he was the most distinguished geologist in the world and not averse to being crowned "King of Siluria" Later he was appointed Director of the Geological Survey. 

But it could not last. Geology was changing. Nemesis came in the form of Charles Lapworth. He was a schoolteacher from Oxfordshire who came to Galashiels to teach English and art. He was intrigued by the local rocks which had recently been mapped by the survey as being Silurian and 26,000 feet thick. 

Murchison had mapped Russia in a few months; Lapworth mapped tiny Dobb' Linn over five or six summers, camped for months at a time in a shepherds hut. The result was the Silurian was reduced from 26,000 feet to 300 and a major unconformity was put in the middle of it! Eventually the Ordovician was defined. 

It took a long time for the Survey to admit the existence of the Ordovician. Not many years ago the Survey would label rock units according to the geological period - all the Carboniferous ones began with a d, c for the Old Red, a for the Cambrian and b for the Silurian. The Ordovician was in there usually with a b!

The geological establishment, especially the Survey, regarded Lapworth as an amateur. After correcting them in the Southern Uplands he moved onto Wales, found more major unconformities, proved the Ordovician and the headed for the North West Highlands where, once more the Survey and Murchison were proved to be fundamentally wrong. Geikie, Murchison's successor as head of the Survey sent his top team to look at the area and they agreed with Lapworth! The first paper confirming Lapworth's findings did not mention Lapworth.

As you can see I found this book fascinating and well written. As far as I can tell the geology is correct. It must be - Dave Green is one of the people who helped him!

Wednesday, 19 May 2021

The Latest Ice Age

The Latest Ice Age 

I joined the Geol Soc Western Zoom lecture yesterday evening and it was fascinating. The amount of knowledge of the latest ice age is fantastic.

THIS WEB PAGE is a good starting point. The interactive map on THIS PAGE summarises the current knowledge - zoom in to see ever greater detail.

Tuesday, 18 May 2021

Glaciers are not Sterile.

Glaciers are not Sterile. 

Jemma Wadham, a professor at Bristol, has written a book, Ice Rivers, (ISBN-10 : 0241467683, ISBN-13 : 978-0241467688) which she introduces in THIS ARTICLE.

She has had a life long love of glaciers and seems to have visited all of them!

She writes about the microbes living in and beneath glaciers. Many live on the soil and other organic stuff below the ice, producing methane - the methanogens. But there are others which consume the methane - the methanotrophs. 

Fast flowing rivers emerging from melting glaciers are super-saturated with methane. No one knows how much methane is trapped in glaciers, some in solid  form as methane hydrate.

What is on the Menu?

What is on the Menu? 

Here is a new word for you - pabulite! Defines as a fossilized meal which never entered the digestive tract. It is different from regurgitalites - I am sure you can work out what that is!

All this comes from an ARTICLE recommended to me by a correspondent. The article is based on an ACADEMIC PAPER in a Swiss Journal.

The source of all these neologisms is a fossil extracted from the Posidonia Shale, part of the Toarcian (early Jurassic) of Germany. It consists of a belemnite which has captured a decapod crustacean. And there is damage to the belemnite suggesting it was predated by some vertebrate. The Early Jurassic shark Hybodus hauffianus is suggested. The shark seems to have dropped its prey before ingesting it - and so we get a pabulite!

The academic paper is very interesting - lots to get your teeth into.

Monday, 17 May 2021

Volcanism and Creativity

Volcanism and Creativity 

A frequent correspondent sent me THIS LINK. Watch it with your loudspeakers turned on.

The current eruption in Iceland has spawned a myriad of videos. This is one of the best.

Thursday, 13 May 2021

Iron and Ice Ages

Iron and Ice Ages 

My "water in the mantle" super correspondent has also sent me THIS LINK. It looks at the connection between low CO₂ in the atmosphere and iron bearing dust in the oceans.

The idea is that the Southern Ocean has lots of the nutrients for biomass but biomass is low. The constraining factor is iron. In ice ages the lack of cover allows dust  - including iron - to be blown out to sea where it allows the formation of  biomass. Some of this sinks and therefore removes CO₂ from the atmosphere.

A fine theory, but how to prove it? More biomass getting to the ocean depths would provide food for deep-sea microorganisms. These would consume oxygen to process the extra food and therefore, in ice ages bottom waters would be oxygen poor. This has been found to be true with modern geochemical measurements.

Figure 1 | The anti-correlated data that inspired the iron hypothesis. a, Measurements of air bubbles trapped in cores drilled from the Antarctic ice sheet show that atmospheric levels of carbon dioxide were significantly lower during the coldest periods (shaded regions) than during modern times (data from ref. 16; CO2 concentrations are shown in parts per million by volume; p.p.m.v.). b, The ice-core records also reveal that more iron was transported to the Southern Ocean in wind-blown dust during the coldest periods than during warmer times (data from ref. 17; iron flux is measured in micrograms per square metre per year). In 1990, Martin2 hypothesized that the increased levels of iron in the Southern Ocean during the coldest periods fertilized the growth of photosynthetic microorganisms in the surface Southern Ocean, which therefore produced more biomass from CO2. This, in turn, would have increased the strength of the biological pump, a mechanism that sequesters some of the biomass (and the carbon within it) in the deep ocean. Martin proposed that the stronger biological pump explains why so much atmospheric CO2 is drawn into the ocean during cold times.