Monday, 26 October 2020

How to Survive a Landslide

How to Survive a Landslide 

This is not likely to affect you in the UK - unless you are in a train near Stonehaven! - but good to know for visits to more exotic parts. THIS ARTICLE summarises THIS LONG ARTICLE which goes into exhaustive details of how a landslide can kill you.

The advice is straight forward.

Before

Check if there are potential dangers of a landslide.

Live in the downhill side of a house.


During 

Move upstairs

Go to interior, unfurnished areas 

Open downhill doors and windows


After 

Make noise so rescuers can find you 

 

Don't 

Open a door out of curiosity 

Shelter beside large furniture

 

The article goes into much more detail, giving reasons for the survival strategies.

P.S. In the accident near Stonehaven it wasn't the landslide that caused the deaths but the train being derailed when it ran into the relatively small amount of landslide debris.

 

Down to Earth Extra - November 2020


DOWN TO EARTH EXTRA - November 2020


The latest edition of Down to Earth Extra is HERE.

And you can read it below.


Thursday, 22 October 2020

Rain Erodes Mountains - Measured and Modelled

 Rain Erodes Mountains - Measured and Modelled

Geomorphology was never like this in my day! A correspondent has brought THIS ARTICLE to my notice - thank you! It is based on THIS JOURNAL PAPER. The research area was Bhutan. 

Rain erodes mountains. Does the removal of material cause mountains to rise because of isostasy? This has been discussed for ever - or so it seems!

The papers describe an attempt to measure this. As you might expect, this is not easy. relief and rainfall at fairly easy to measure but erosion rates are more difficult. The method used here is to measure chemical changes in quartz sand caused by cosmic rays. This goes by the name "detrital cosmogenic nuclide erosion rates".
Presumably fewer changes mean faster erosion. The longer the sand is on the surface the more cosmogenic nuclides and slower erosion.

It is thought that erosion rates are roughly equal to uplift rates as the landscapes are thought to be in equilibrium.

The papers quantify how rainfall affects erosion rates in rugged terrain. And that tectonic activity is affected by rainfall!

The geomorphology i was taught was a descriptive subject. Reading this paper shows thait has changed! But you still get to go to interesting places.

Tuesday, 20 October 2020

Gilbert Green RIP

 Gilbert Green RIP

Gilbert Wilson Green, who was a surveyor with the British Geological Survey and author of many West Country memoirs has died. 

He led many field trips for Bath Geol Soc and WEGA. 

Isobel Geddes (isobelgeddes@talk21.com) writes:-


Dear All,
I am sorry to report that Gilbert died nine days ago in his home.  His
sons had been taking turns to stay and care for him over a number of
years as he became increasingly frail.
We all know he had an extremely interesting life of which we were a
part, from time to time, during the last 20-30 years. So if you have any
particular memories or these times, his family would appreciate your
writing a few words and sending them to son Robert (copied into this
email) as they compose his obituary. I certainly have notable memories
of our geological adventures!

Due to Covid restrictions, his funeral, in Edington Priory church on
30th October, will be attended just by his family, though we may have
the opportunity to privately visit the church prior to this date.

Regards.
Isobel

Monday, 19 October 2020

Naughty Fossils?

 Naughty Fossils?

Many organisations have been holding "Virtual Meetings", mostly quite successfully. But I came across THIS REPORT in the Guardian which tells of a less satisfactory event.

Apparently the organisers for the US-based Society of Vertebrate Paleontology used a filter which rejected certain words considered unsuitable. The words suppressed might be unsuitable in many circumstances but not when discussing ancient life. 

Not wishing to shock my readership I will not repeat the naughty words - those of you of sufficiently strong minds can read the article. And NO giggling!

Lake Kivu - Dangerous and Useful!

 Lake Kivu - Dangerous and Useful!

A correspondent brought THIS ARTICLE to my attention. It gives a very readable introduction to the rather unusual limnology of Lake Kivu, on the border between Rwanda and the Democratic Republic of the Congo.

The lake is large and the water is stratified. The surface water (the uppermost 60m) is normal. The rest (down to 460m) is full of carbon dioxide and methane, coming from hot springs in the bottom of the lake. And the two layers do not mix.


The unusual separation of layers of the lake is at the core of its volatility (Credit: D Bouffard & A Wuest/AR Fluid Mechanics 2019/Knowable Magazine)

There was a similar situation at Lake Nyos in Cameroon. There was little or no methane here but in 1986 the CO₂ was released (by a landslide) and 1,800 people suffocated. This is unlikely to happen at Lake Kivu, but the lake is constantly monitored.

But lately the methane is being exploited as a fuel source to generate electricity - something which is badly needed in the area.

The article gives you far more information than I have - well worth reading!

Thursday, 15 October 2020

Mammals are Warm Blooded - not Quite!

 Mammals are Warm Blooded - not Quite!

The following article has been republished from The Conversation. A link to the original can be found at the bottom of the page. 

Do you like this means of quoting the article? - let me know.

Two Bristol researchers used X-rays from synchrotron sources to count the growth rings of fossil teeth of early mammals from South Wales to gauge their ages and blood flow. And discovered that they were between reptile and modern mammal ranges. 

Did warm bloodedness come later?

AND a correspondent has brought THIS RELATED article to my attention  - Thank You!

Fossilised teeth reveal first mammals were far from warm blooded

Artist’s impression of early mammals. John Sibbick/University of Bristol, Author provided
Elis Newham, University of Bristol and Pam Gill, University of Bristol

Warm blood is one of the key traits that led to the success of mammals as they evolved from scurrying beneath the feet of dinosaurs to spreading into the wild and wonderful collection of animals we know today. But our new research, which involved X-ray scanning hundreds of fossilised teeth, suggests the first mammals were more like cold blooded reptiles, and that warm blood evolved much later.

Warm blood helps us maintain our body temperature regardless of our environment, allowing us to gather food at night and in cold climates, and helps us stay active for longer than our cold blooded relatives. However, exactly when, why, and how this evolved is still poorly understood.

We know from tiny fossils of bones and teeth that mammals first evolved over 200 million years ago, and had many of the traits we associate with mammals, such as specialised chewing teeth and bigger brains. But the physiologies (how an animal’s body works day-to-day) of these animals is difficult to estimate using traditional methods, as this relates to soft organs that aren’t usually fossilised.

Our new research, published in Nature Communications, now offers a glimpse into the physiologies of the first mammals, by pioneering X-ray imaging to count growth rings in their teeth and measure blood flow through their bones. Although it had previously been assumed that even the earliest mammals were warm blooded, this research suggests that they still had some way to go before developing warm blood and its benefits that we enjoy today.

Long lifespans and slow metabolism

Working with a 20-strong international team of scientists, we have estimated the lifespans of the earliest mammals for the first time. This was done by X-ray scanning hundreds of fossilised teeth found in south Wales of two tiny mammals, Morganucodon and Kuehneotherium, from the Early Jurassic epoch.

High-resolution scans performed at powerful “synchrotron” X-ray sources in Switzerland and France allowed us to count annual growth lines preserved in the fossilised cementum of these teeth. Cementum is the little-known tissue that anchors mammal tooth roots to the jaw, recording every year of an animal’s life by growth lines that can be counted like tree rings to estimate lifespan.

X-ray image of round shape containing concentric rings.
X-ray image of tooth cementum from Morganucodon revealing growth rings. University of Bristol, Author provided

These lines are counted in living mammals by grinding teeth down into thin sections that can be studied using microscopes. As this destroys the tooth, we could not do this with precious museum fossils, and so we used X-ray imaging. Counting rings in our fossil mammal teeth gave a lifespan of 14 years for Morganucodon, and nine years for Kuehneotherium.

These are significantly, and surprisingly, longer lifespans than those of similar, shrew-sized mammals living today whose wild lifespans rarely exceed two to three years. This suggests a dramatically slower metabolism, or pace of life, than living mammals, and instead more closely resembles that of living reptiles.

Low activity levels

The size of the openings for the major blood vessels running through an animal’s limb bones is known to be proportionate to the levels of sustained activity (such as hunting and foraging) that they are capable of: smaller size suggests lower activity levels.

When we measured this in the femur of Morganucodon, we found that, while smaller than living mammals, they were also higher than those of living reptiles. This suggests that early mammals had an intermediate ability for sustained activity, between warm blooded mammals and cold blooded reptiles.

University of Bristol

This combined approach of studying the lifespans and activity levels of early mammals provides the first direct window onto several aspects of how they lived. We can see that our earliest relatives kept a much slower pace of life, but had definitely started on the road to the active lifestyles of living mammals today.

We shall continue these studies through the early mammal fossil record, to shed light on the first steps towards the modern mammalian lifestyle, and when we truly became warm blooded.The Conversation

Elis Newham, Research Associate in Palaeontology, University of Bristol and Pam Gill, Senior Research Associate in Palaeontology, University of Bristol

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Thursday, 8 October 2020

Build the Alps - Pulling or Pushing?

 Build the Alps - Pulling or Pushing?

A correspondent has brought THIS PAPER to my attention. We used to think that the Alps were built by the Adriatic plate pushing against the Eurasian one, pushing lots of stuff to create the mountains.

But the seismicity of the Alps is characteristic of expansion, not of the compression that you would expect. The paper tries to explain this and other phenomena.

The explanation given that, as the Adriatic plate, especially the continental part abutted the Eurasian plate (30 Ma ago), the upper, lighter, crust of Eurasia, separated from the lower, denser mantle. Being lighter it surged upwards (no doubt, at a suitably stately pace) to form the Alps.

The sinking of the lithosphere sucks the Adriatic plate northwards.

Reading the article may help to understand it - I am struggling with it. Where do these wonderful nappes come in?

The Journal article may help but you need some form of subscription to access. THIS gives the abstract. But a "high-resolution, rheologically consistent, two-dimensional visco-elasto-plastic thermo-mechanical numerical model" seems a bit above my pay grade!

Friday, 2 October 2020

Neanderthals at Risk from COVID-19?

Neanderthals at Risk from COVID-19?

THIS ARTICLE gives an interesting perspective on genetics. It is well known that most of us have some fragments of Neanderthal DNA in our genome. This happened when Anatomically Modern Humans (AMH) left Africa and interbred with Neanderthals in Eurasia. A few Neanderthals went the other way but most Africans have very little Neanderthal DNA.

Fast-forward a few millennia and Covid-19 arrived. And it was found that if you had a section of code on chromosome-3 you were more likely to have a severe (unfortunately often fatal) reaction to COVID. And this section of code is very similar to that in the Neanderthal genome!

You can find the original paper HERE.

Is this why COVID-19 mortality is lower in Africa than one might expect?

Wednesday, 30 September 2020

Down to Earth Extra - October 2020


DOWN TO EARTH EXTRA - October 2020


The latest edition of Down to Earth Extra is HERE.

And you can read it below.

Tuesday, 29 September 2020

Viruses can be Fossilised

 Viruses can be Fossilised

Professor Maurice Tucker has sent me a PAPER ON VIRUSES which he recently published in "Geology Today" which is very interesting - in several ways! 

We are all suffering, directly or indirectly, from the coronavirus. If you want a good introduction to what a virus is, Professor Tuckers paper is a good place to start. 

The numbers of viruses in almost anything are phenomenal. A normal size person may have tens of trillions of bacteria in their body, but there may be ten viruses for every bacteria. But they are much smaller. You may have 200 grams of bacteria in your body, but the much larger numbers of viruses may weigh less than 10 grams.

The only way to see a virus is with an electron microscope. So your hand lens will not be of much use to find a fossilised virus. The paper has electron microscope pictures of modern viruses being fossilised. It seems that they can become nuclei for minerals to form around, destroying their shape.

Transmission Electron Microscope (TEM) images from a biofilm showing silica nanoparticles with cores of virus-like particles and solid silica nanoparticles within a bacterial cell (a) and close-up (b), from a hot spring in China. (Images courtesy of Xiaotong Peng, Chinese Academy of Sciences, Sanya, China.)

There is lots of good stuff in the article, including a discussion on the origin of viruses and of life itself. A rewarding read!

Monday, 21 September 2020

Another Mass Extinction!

 Another Mass Extinction!

Mike Benton of Bristol University wrote THIS ARTICLE last week. So, rather belatedly, it appears here.

The extinction event was rather difficult to recognise. We knew of 5 such events - now we have 6. It happened 233million years ago, in the middle of the Triassic, and is called the Carnian Pluvial Episode (CPE) and seems to have killed off as many species as the asteroid at the end of the Cretaceous.

The ending of the tetrapods left a space which the dinosaurs filled for the next 165million years.

A timeline of mass extinction events. D. Bonadonna/MUSE, Trento, Author provided

The CPE was first noticed in Europe, to which, it was thought to be restricted. Then its time correlation with the eruption of the Wrangellia basalts was noticed. I had not noticed the concept of Wrangellia until now, but it seems to be one of the terranes welded onto the west coast of North America.

The Wrangellian eruptions led to acid rain - it is a Pluvial event! - which acidified the oceans and cleaned off the land surface. When the eruptions stopped so did the rain but temperatures remained high - dinosaur weather!

The effects in the oceans were great. Before the CPE carbonates in the oceans came from microbes. After it was coral reefs and plankton.

Saturday, 12 September 2020

Where Does the Carbon in Diamonds Come From?

Where Does the Carbon in Diamonds Come From? 

this week I found THIS ARTICLE on the Earth-logs blog. It is based on THIS PAPER. It was thought that the carbon came from subducted sedimentary rocks. Then we thought of the basalts in the oceanic crust. Their reaction with aqueous fluids results in carbonates.

Current research uses the isotopic chemistry of carbon and nitrogen in the diamonds and the tiny silicate minerals included in them. Most of these are garnets. From the studies the depth of formation can be indicated and this can help determine the carbon source.

And it seems that the oceanic basalts are the favoured source.

But VERY deep diamonds - formed below 660km - may be different. The isotopes suggest that the carbon source is within the mantle and ultimately the stellar dust that accreted to form the earth. But at that depth the carbon is incorporated in metals and carbides. The authors suggest that subducted slabs, reaching that depth, release watery fluids which mobilise the trapped carbon and allow the formation of diamond.

Diamond crystal containing a garnet and other inclusions (Credit: Stephen Richardson, University of Cape Town, South Africa)




Friday, 4 September 2020

Hibernation is Not New

 Hibernation is Not New

A correspondent brought THIS ARTICLE to my attention.

Lystrosaurus is the creature which survived the end-Permian mass extinction. In the Triassic they were found all over Gondwanaland. The specimens used in this study came from what is now Antarctica and South Africa. In Triassic times Antarctica was within the Antarctic Circle, South Africa outside it. 

Lystrosaurus is characterised by having tusks, which like elephants tusks, grow throughout their lives. And they have growth rings. The South African specimens have regularly spaced rings, the Antarctic ones have the same but also closely-spaced, thick rings.

a A cross-section of Antarctic specimen UWBM 118025 with a “hibernation zone” highlighted at a higher magnification. Scale bars = 1000 μm. b Well-preserved regular incremental growth marks from the South African specimen UWBM 118028, lacking “hibernation zones”. Arrows denote individual lines with an average spacing of 16–20 μm. Scale bar = 100 μm.

The authors argue that this indicates the Antarctic creatures were hibernating - or something very like it. Which is not really surprising but nice to have some evidence for it.

The original article is HERE.


Tuesday, 1 September 2020

Methane Outgassing in Siberia

 Methane Outgassing in Siberia

By chance I came across THIS STORY in the Siberian Times. it seems, that with global warming methane is being released by the permafrost, often with spectacular results.

 The new funnel filmed from air by the team of Yamal-based TV station. Picture from July 2020 by Vesti Yamal. Note the figures for scale.


The other pictures in the article are equally spectacular. 



This is a rather worrying development. Methane is a more powerful greenhouse gas than carbon dioxide and there is believed to be vast quantities of it captured in the permafrost. If it continues to be released it will trigger a vicious circle.


Saturday, 29 August 2020

Tuatara Genome Revealed

Tuatara Genome Revealed 

A correspondent has brought THIS ARTICLE to my notice. It tells of how the genetic material of the tuatara was collected, in collaboration with the iconic species Maori guardians. Without their cooperation the material could not have been gathered. 

The genome is 50% larger than the human genome and is one of the largest ever published. One purpose was to reconstruct the creatures evolutionary tree.

A tuatara in New Zealand. Credit: Pete Oxford/NPL


And here is its evolutionary tree - the simple version.
 Refining the evolutionary tree for reptiles, birds and mammals. This phylogenetic tree includes six branches: mammals and five branches within a clade called sauropsids, which comprises reptiles and birds. One of these, the Rhynchocephalia, has only one living member, the tuatara. Gemmell and colleagues date the divergence of the Rhynchocephalia from the Squamata to about 250 million years (Myr) ago


And here is the more complex version, taken from THE ORIGINAL PAPER.

a, The tuatara, (S. punctatus) is the sole survivor of the order Rhynchocephalia. b, c, The rhynchocephalians appear to have originated in the early Mesozoic period (about 250–240 million years ago (Ma)) and were common, speciose and globally distributed for much of that era. The geographical range of the rhynchocephalians progressively contracted after the Early Jurassic epoch (about 200–175 Ma); the most recent fossil record outside of New Zealand is from Argentina in the Late Cretaceous epoch (about 70 Ma). c, The last bastions of the rhynchocephalians are 32 islands off the coast of New Zealand, which have recently been augmented by the establishment of about 10 new island or mainland sanctuary populations using translocations. The current global population is estimated to be around 100,000 individuals. Rhynchocephalian and tuatara fossil localities are redrawn and adapted from ref. 1 with permission, and incorporate data from ref. 2. In the global distribution map (c, top); triangle = Triassic; square = Jurassic; circle = Cretaceous; and diamond = Palaeocene. In the map of the New Zealand distribution (c, bottom); asterisk = Miocene; cross = Pleistocene; circle = Holocene; blue triangle = extant population; and orange triangle = population investigated in this study. Scale bar, 200 km. Photograph credit, F. Lanting.

 The papers are interesting as they give an insight into modern biology. 

Down to Earth Extra - September 2020

 

DOWN TO EARTH EXTRA - September 2020


The latest edition of Down to Earth Extra is HERE.

And you can read it below.


Wednesday, 19 August 2020

Zoom Geological Webinars from Cardiff University

 Zoom Geological Webinars from Cardiff University

The School of Earth and Ocean Sciences at Cardiff University is organising a series of Zoom webinars, held at 5PM on Wednesdays.

You can read all about it HERE. Instructions on how to join the webinar are on the site.

I have missed the first couple of seminars but the full list is as follows:- 


Dave Green's Geostudies Programme

 Dave Green's Geostudies Programme

In these uncertain coronavirus times, Dave Green has boldly gone and put together a programme for the rest of this year and next. Let us hope it can go ahead as planned! Dave can be contacted HERE.


Dave writes:-

Saturday, 15 August 2020

Landslides and the Railways

Landslides and the Railways 

There has been much on the airwaves and in the papers about the dangers climate change induced landslides pose for the railways. A correspondent sent me THIS which shows that the same concerns have worried people in the railway industry, over the years. 

The paper covers the methods used to determine where conditions are suitable for landslides to occur. It does not present its results in sufficient detail to see whether the place where the recent derailment near Stonehaven was classed in its hierarchy of landslide possibilities. That was not its purpose.

But Network Rail and the BGS do have that information. This will show whether the area was a risk. But it will not tell you that a landslide will occur on a particular day. I suspect that predicting landslides is similar to predicting earthquakes!


Tuesday, 11 August 2020

Ocean-going Crinoids

Ocean-going Crinoids 

Those well known fossils, crinoids, are often found attached to, what are now, small pieces of coal. Originally these were pieces of driftwood.

Fossil crinoid attached to coal

William Buckland (and very possibly, Mary Anning) suggested that the crinoids had been attached to pieces of driftwood while alive, living suspended underneath it. For many years this was thought to be an impossibility - the weight of the crinoids would have caused the driftwood logs to sink.

But the author of THIS ARTICLE, and his co-workers, using many different sorts of advanced techniques, has worked out that crinoids do indeed hang suspended underneath the driftwood but clustered towards one end of it. Such a log could drift for ten to twenty years.

So now we know! The original article is HERE

Artists impression of a crinoid raft.

Friday, 7 August 2020

What was Tanystropheus?

What was Tanystropheus? 

A correspondent has brought THIS ARTICLE to my attention. And the answer, according to the researchers, is an aquatic creature. And not one I would like to meet in a non-fossilised form - it was active 242m years ago. It was up to 6 metres long, with a long stiff neck. Fortunately its head, and teeth were small.

The researchers conclude that there were two species of Tanystropheus - the larger hydroides and the smaller longobardicus. The newspaper article is based on THIS ARTICLE which has all the details.

An artist’s impression of Tanystropheus, fossils of which were first found around 150 years ago. Photograph: Emma Finley-Jacob/University of Zurich/Current Biology

Thursday, 6 August 2020

Geology from your Sofa

Geology from your Sofa

In this time of enforced isolation the Geologists' Association, (the GA) has produced the "Geology from your Sofa" web page. You can find it HERE. There is a tremendous amount of stuff to read and look at.

Well worth clicking on!



Short Field Course 2020 from Dave Green

Short Field Course 2020 from Dave Green

Dave Green is suggesting a short field course of 3 excursions. I received his advertisement on the day of the first one so there are 2 awaiting your presence. 

The advertisement and details are HERE. Or you can read it below.


GEOSUFFOLK TIMES

GEOSUFFOLK TIMES

THIS has come across my desk and is a pleasant read. It is also reproduced below.


Down to Earth Extra - August 2020

DOWN TO EARTH EXTRA - August 2020


The latest edition is a 2 page introduction to the 40 page Down to Earth magazine which is not being printed - unless you ask Chris Darmon for a specially printed one.

The 2 page Extra is HERE.

The 40 page Magazine is HERE.

If you prefer smaller downloads they are HERE and HERE

Or you can read Down to Earth Extra below.

And Down to Earth Magazine below that.





Thursday, 30 July 2020

Where Did Stonehenge's Sarsens Come From?

Where Did Stonehenge's Sarsens Come From?

I came across THIS ARTICLE and then a correspondent sent me the link to the ORIGINAL SOURCE. Stonehenge is a never ending subject. These articles are well worth looking at.

Sarsen stones are post-glacial silcretes - quartz sandstones with a quartz cement and are - almost - 100% silica. The authors discuss the place of origin of the sarsens. Almost all of them have an identical trace element composition and they use this to identify a place with an identical chemical signature. 

This is West Wood, 25 km to the north of Stonehenge. As some of the sarsens weigh about 30 tonnes, this would not have been a trivial undertaking!



Wednesday, 22 July 2020

The East African Rift System and Landslides

The East African Rift System and Landslides

When I think of the East African Rift System, landslides are not the first thing on my mind. THIS ARTICLE from one of my most prolific sources, Earth-logs, may make me change my mind. 

The "Rise to the Rift" was much mentioned many years ago. We now know what causes it - bulging of the continental crust resulting both from its unloading by thinning along the rifts and the buoyancy conferred by high heat flow in the mantle beneath - but the result is landslides.

The East African Rift System (Credit: P.C. Neupane, M.Sc thesis 2011; Fig. 1)

There is enhanced erosion, both into the rift and outwards, especially onto the the Indian Ocean continental shelf. Recent oil exploration work, offshore Tanzania, has illuminated this.

In particular it has shown the presence of a vast submarine landslide, called (intriguingly) the Mafia mega-slide. It is thought that it was caused by a large earthquake and would have caused a large tsunami.

Seismic reflection profile parallel to the Tanzanian coastline with the Mafia mega-slide highlighted in green (Credit: Maselli et al. 2020; Fig. 5)

You can find details of this work HERE. The main thrust of the paper is using the records of offshore sedimentation to fix the dates of the rifting and to note the dangers of future submarine landslides.

Tuesday, 21 July 2020

Active Volcanoes on Venus?

Active Volcanoes on Venus?

THIS ARTICLE in a newspaper tells of an interpretation of ring structures on Venus, found using radar, as being volcanic in origin. They call them coronae structures - the trench surrounding the peaks. The researchers think the coronae are fields of lava flows and major faults.

They suggest that such structures can only be produced by volcanic activity. And many of them were active in the last few million years.

Two coronae on the surface of Venus which are formed when hot material from deep inside the planet rises through the mantle. The black line shows a gap in the imaging data. Photograph: Laurent Montesi/Reuters

The newspaper article is based on a paper in Nature Geoscience, which you can read HERE