Monday, 23 November 2020

DOWN TO EARTH EXTRA - December 2020


DOWN TO EARTH EXTRA - December 2020


The latest edition of Down to Earth Extra is HERE.

And you can read it below. 




Saturday, 21 November 2020

Back Numbers of Magazines Available

 Back Numbers of Magazines Available

A mature WEGA member has some old magazines available for anyone who wishes them.

She writes:- 
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Available are #s 45, 47-60, 62-654,66-81,83,85-97 and 99-110 of“ Down to Earth”

and 

#s 23-35 (missing#33) of “Earth Heritage”

I am not agreeable to handing out single copies. Recipient must take all available of either series and do any picking and choosing on their own territory. First come, first served. 

If these magazines are unwanted they will go for recycling with the Council collection in a few weeks time. Soon or never!

----------------------------

If you are interested contact me at graeme@churchard.com and I will give you the contact details. 

Tuesday, 17 November 2020

Urban Geology (mostly London, I'm afraid)

 Urban Geology (mostly London, I'm afraid)

Roger Steer has brought THIS WONDERFUL RESOURCE to my notice. It is an excursion guide to the rocks of the built environment, mostly of London, but with a little of Birmingham and Doha, Qatar. It is mainly the work of Ruth Siddall of University College, London, following on from the work of Eric Robinson.

The amount of work which has gone into the many articles is phenomenal. I learned more about Larvikite by reading the London Pub article than I knew before. It is not a syenite but a monzonite with equal amounts of plagioclase and K-feldspar. These are in the form of interlaced laminae forming an antiperthite. These antipethitic feldspars are iridescent and this is known as schillerescence.

But it is not only igneous rocks which are discussed in detail. The fossils of Portland Stone are described and illustrated.

Two sections through once articulated valves of L. gibbosa, now leached away. By chance, the mason has cut through along the long axes of the shells giving the effect of ‘angel wings’. The ribs and costae can be seen on the upper example of the two. Once again, this is from the Roach used on the new wing of BBC Broadcasting House. 

One photograph illustrates that this is indeed Urban Geology - the scale is indicated by a fag end!

I have just started reading this huge archive and it is a cornucopia of geological insights and delights! A pity it is mostly in London. 



Saturday, 7 November 2020

Food Webs - Back to Basics

Food Webs - Back to Basics 

A correspondent has brought THIS ARTICLE to my attention. With great difficulty I avoid all scatological humour and tell you that it is about Rhaetian food webs in the Bristol area. The research material was coprolites from Chipping Sodbury. CT scans were taken of the coprolites and the contents (remarkably well preserved) identified. 

The animals of the Rhaetian sea were all carnivores and they ate each other. The one rule was - If it is smaller than you, eat it!

The article, which is a precursor for a paper which will be published in the Proceedings of the Geologists' Association, is largely concerned with building a food web of the Rhaetian Sea. What I find fascinating is the preservation of the bones. Modern animals have stomachs which can dissolve bones. For these creatures going to the toilet must have been painful!

CT scan of coprolite specimen, BRSMG Cf15546, in different views, showing tuberculated bone (blue) from a fish skull, and two vertebrae from the tail of the marine reptile Pachystropheus, in yellow and green.
Marie Cueille, and Palaeobiology Research Group, University of Bristol



Friday, 6 November 2020

The Longest Erupting Supervolcano ---?

The Longest Erupting Supervolcano ? 

--- Kerguelen!

I have been facinated by Kerguelen since reading "Desolation Island" by Patrick O'Brian - the fifth book in his Aubrey - Maturin series. Desolation Island is, of course, Kerguelen.

Another reason to find the place interesting is THIS ARTICLE which tells us that the Kerguelen Plateau was a Large Igneous Province (LIP) which erupted for over 30 million years. Most LIPs last less than 5 million.

Eruption started at 122 million and lasted until 90 million. From about 100 million to 20 million years ago it was above sea level, with trees growing. These have been recovered in recent deep sea drilling.

The plateau has since subsided with only Kerguelen and Heard and McDonald islands poking above the waves. Most is at depths of 1,000 to 2,000 metres. The surrounding oceans are at 4,000m.

The article gives a lot of the details and is an easy read - well worth looking at.

The thought of huge islands (half the size of Australia) disappearing gives one food for thought!


Location of the Kerguelen Plateau in the Indian Ocean. NATIONAL GEOPHYSICAL DATA CENTER

Wednesday, 4 November 2020

Geological Ladies

 

Geological Ladies

A correspondent has brought the following articles from the Geol Soc to my attention - Thank You! 

To get the rest of this post click the second read more at the bottom of the page - there is a LOT MORE!

Free for a limited time Ladies with hammers – exploring a social paradox in early nineteenth-century Britain


By M. K├Âlbl-Ebert

In the early nineteenth century, long before the Geological Society of London opened its doors to female members, geology was a fashionable science in Britain. Numerous women collected fossils and minerals, and read or even wrote popular geology books. There was also a considerable number of female helpmates to renowned pioneers of geology, acting as secretaries, draughtswomen, curators and field geologists...read more