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?