Thursday, 26 November 2015

Charles Lyell among the Romantics

Loess people are interested in Charles Lyell because, in 1833, he described the Rhine loess in volume 3 of the Principles of Geology, and thus made loess known around the world..  Lyell lived and worked in the so-called Romantic epoch, he played a part in changing the way in which we see the world; he was part of a great movement of writers and scientists which made the modern world. People like Humphrey Davy were inventing science (William

 
 


Whewell was naming it); Lyell was inventing modern geology. Lyell was part of this Romantic community- so were Mary Somerville(above) and Sam.Coleridge, and many others and lesser lights like Poulet Scrope and Leonard Horner and Sam.Hibbert.

Sources: Michael Ferber 2010, Romanticism: A Very Short Introduction, Oxford University Press, 148p:
"Most of the Romantics ...  saw in the latest discoveries of science a confirmation of their intuition that deep within the natural world and deep within their souls was a living bond, and that in certain heightened states of mind they could understand the language nature spoke."

Sources: Richard Holmes 2008, The Age of Wonder: How the Romantic Generation discovered the Beauty and Terror of Science, published by Harper in 2008, paperback in 2009. This is what Oliver Sacks said about the book:
"I am a Richard Holmes addict. He is an incomparable biographer, but in The Age of Wonder, he rises to new heights and becomes the biographer not of a single figure, but of an entire unique period, when artist and scientist could share common aims and ambitions and a common language- and together create a 'romantic', humanist science. We are once again on the brink of such an age, when science and art will come together in new and powerful ways."
 Humphry Davy
 
Sources: Romantic Circles www.rc.umd.edu : Romantic Circles is an academic peer-reviewed website dedicated to the study of Romantic literature and culture. It is published by the University of Maryland and supported by the Maryland Institute for Technology in the Humanities MITH, and the English Departments of Loyala University Chicago and the University of Maryland. Loess makes an appearance on Romantic Circles via their publication of the Map from Sam.Hibbert's book on the Volcanos of the Eifel Region. The book included, as a frontispiece a map of the Eifel region drawn by Charlotte Hibbert. We believe that this might be the first geological map to show loess (published in 1832); the map is reproduced by Romantic Circles and is available on the website..
 
 
 
 
 

Tuesday, 27 October 2015

Samuel Hibbert: History of the Extinct Volcanos of the Basin of Neuwied, On the Lower Rhine

 
The sketch is by Charlotte Hibbert and decorates the title page of the Hibbert Volcanos book- it was much admired by Charles Lyell. Charlotte also drew the map which forms the frontispiece of the book. 'Loess Ground' offers the opinion that this might be the first time that loess appeared on a geological map; the book was published in 1832 by W & D Laing in Edinburgh
 
 
 

Samuel Hibbert- this could be the only picture of SH; it would be good to have a few more; keep an eye open for SH pictures.

Friday, 9 October 2015

Desert Loess: Tales of four deserts- Sahara, Australia, Central Asia, China.

Sahara.  The Sahara is the great desert; the default desert. Albrecht Penck considered this place and observed that it 'lacked a loess girdle'  no significant deposits of loess around the Sahara.  Maybe a few modest possible deposits, but no great deposits. Plenty of dust produced in the Sahara and North African regions; huge amounts of dust from old lake beds- but this was all 'critters & clay' not loess material. It appeared as though the Sahara did not contain a loess making mechanism; there were no natural processes operating in the great desert that produced the sort of material that made loess deposits.

Australia.  Bruce Butler, the scion of CSIRO pedologists, wandered the deserts of Australia all his life; he reported a remarkable absence of loess- he suggested that desert loess was just a myth, a fairy story. People have looked since BB time but the great loess deposits have failed to appear. There are a few modest possible deposits- places for the Rainbow bird to nest- but no great loess. A large desert continent- but lacking in loess deposits.

Central Asia.  There are deserts in Central Asia, and there is loess. Now- how is it possible to have deserts & Loess in Central Asia- and what is the connection?  The connection is part of a larger connection; the region also has high mountains (the western end of High Asia) and large rivers (Syr-Darya, Amu-Darya). Put all together and we can make a loess system. Loess material does accumulate in the deserts of Central Asia but it is made in the mountains and delivered by rivers. The deserts are loess material reservoirs, stuff is blown out of the deserts and forms loess deposits. Andrei Dodonov worked this out; G.A.Mavlyanov got close but could not quite reach the last stages. It was hard for Soviet scholars to actually embrace aeolian deposition.

China.  The Sahara is the mighty desert but the Chinese loess lands are the great loess landscapes. Tom Stevens has been looking at zircons and can tell us now how loess material was made in the mountains of High Asia and delivered via the Yellow River to the loesslands. Sun Ji-min has been following in the footsteps of Liu Tung-sheng and demonstrating the marvels of the Chinese loess. The Chinese loess is like the Central Asian loess; mountains and rivers are involved. Loess material is made in high cold mountains. We now realise just how many mountain glaciers were/are in High Asia. Glaciers make loess material, as John Hardcastle observed in Timaru 127 years ago.

Postscript- Mars.  Another desert, a real desert. Some particulates blowing around; but it all looks a bit Sahara-like. The machines are wandering about, mechanical Martian versions of Bruce Butler, but they are not finding spectacular loess deposits. Can this entire planet lack loess deposits?  Is there no mechanism to produce loess material that ever operated on Mars?  It would seem not. Pity.

Tuesday, 22 September 2015

Monday, 21 September 2015

Charles Darwin and the Loess of the Rhine Valley

There is only one mention of loess in the 'Origin of Species'.  It contains an interesting assumption and an interesting deduction:

"We have evidence in the loess of the Rhine of considerable changes of level in the land within a very recent geological period, and when the surface was peopled by existing land and fresh-water shells."

Darwin deploys Lyell's hypothesis for the formation of the Rhine loess. The Lyell idea would not be replaced until around 1890 when the Aeolian theory became dominant.

Monday, 7 September 2015

Leonard Horner (1785-1864)

Leonard Horner: geologist and loess enthusiast. Also father of six daughters and inspector of factories who worked hard to improve the conditions in British mills and factories in the nineteenth century. His efforts on behalf of the workers gained him plaudits from Karl Marx in the pages of Das Kapital. Friend (and father-in-law) of Charles Lyell; they shared an interest in loess- Lyell the scholar & Horner the enthusiast. He was the first loess enthusiast. Read about him in the great book by Patrick N.O'Farrell.
"Leonard Horner, einer der Factory inquiry Commissioners von 1833 und Fabrikinspektor, in der Tat Fabrikzensor, bis 1859, hat unsterbliche Verdienste um englische Arbeiterklasses gewonnen" Karl Marx Das Kapital 1867.

Monday, 20 July 2015

Charles Lyell: Loess Encounters of Three Kinds

For the moment we identify four really critical pioneers in the development of the study of loess. Four people who carried things on from 1824 and Karl Caesar von Leonhard publishing the first real description of loess in 'Charakteristik der Felsarten'(CdF). The four demarcated pioneers are Charles Lyell, F.von Richthofen, V.A.Obruchev and L.S.Berg. The people who provided the paradigms for loess formation.
From here, from Leicester, the easiest of these to study in detail is Charles Lyell. All four were honoured by their countries of birth and inhabitation but Charles was the one who probably fitted most comfortably into the society of his day. He left a lot of records and there is quite a lot of published biobibibliographical detail. We consider three problems of detail, of behaviour- all relevant to loess. L.G.Wilson in his biography of Lyell touches on the loess connection, but only very lightly; we would like to enlarge.
The three encounters of interest are: (a) in conversation; who did he talk to about loess? when did he first encounter loess in conversation? we know that he talked about loess with Sam. & Charlotte Hibbert at their house in Edinburgh on 5 September 1831- was that his first conversational encounter?  (b) in the field: when did he first see the actual material? we have records of him seeing the loess in 1832 when he was on his post-wedding trip with Mary Horner down the Rhine. We are fairly sure that Bronn and/or KCvL showed them some loess. (c) in the literature- this is a tricky question; obviously in the early 1830s there was very little loess literature- what did Lyell see. Hibbert was a great fan of KCvL and we speculate that when Lyell was with the Hibberts in 1831 H showed him a copy of CdF (pure speculation). Lyell wrote about loess in vol.3 of Principles, and this was the key 'spreading the word' moment. What did he know in 1831? We know he made a 6 day visit to the Eifel region in mid-July 1831 (some authorities call this a 6 week excursion but they have been mislead by a very confusing Lyell letter)- did he see loess? did he see only the volcanic stuff he had gone to examine?

 

Friday, 12 June 2015

Eric Gill: Loess Fantasy

Eric Gill(1860-1940) was a well-known graphic artist, sculptor and typeface designer. He was also notorious in various other ways. The picture here is his illustration for 'The Taming of the Shrew' by WS, from the New Temple Shakespeare edition by J.M.Dent of London (1934) . Loess Ground has added the loessic aspects. The falling dust aspect is probably correct, but the agency may be in doubt.

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Monday, 1 June 2015

Flow-stick transition in granular materials

The flow-stick transition has been placed at about 50um for dry mineral particles (Smalley 1964, Jones & Pilpel 1966a,b). Particle systems with particles less than 50um are cohesive; with larger particles flow through an orifice is possible. As particle size increases the flow rate increases, gravitational forces overcome cohesive forces. If flow is observed using a 3mm orifice there is a transition point at about 150um.

Bingham, E.C., Wikoff, R.W.  1931.  The flow of dry sand through capillary tubes. Journal of Rheology  2, 395-400.

Jones, T.M., Pilpel, N.  1966a.  The flow properties of granular magnesia.  Journal of Pharmacy & Pharmacology 18, 81-93.

Jones, T.M., Pilpel, N.  1966b.  The flow of granular magnesia.  Journal of Pharmacy & Pharmacology  18, 429-442.

Smalley, I.J.  1964.  Flow-stick transition in powders.  Nature 201, 173-174.


The simple picture is the graph from Smalley (1964); this is crushed quartz passing through a 3mm orifice. A beautifully clear picture of the flow-stick transition ( and probably the first one). At point S flow stops because the gravity forces producing flow are counter-balanced by the cohesive forces in the system. This is at about 50um- an interesting size for all loess people. At point B the orifice is blocked- the particles are simply too large to pass through, simple jamming. Point T is interesting; here is where cohesive forces really begin to be felt; to the left of M cohesive forces are dominant; to the right of M gravity forces are dominant.
Sorry about the sideways nature of this picture. This is from Jones & Pilpel(1966a). Magnesia instead of quartz; a beautiful set of curves; note point S- nicely placed at about 50um, the various aperture sizes are indicated. An interesting observation from the complex picture is that the 3mm aperture was causing a definite 'container' effect. T point is at about 250um, this is clearly observed from the values of flow through the larger apertures. In a general system cohesion effects kick in at sizes below about 250um.
We cite Bingham & Wikoff (1931) because they were possibly the first people to study the flow of granular materials through orifices(?) and because their simple experimental set-up was followed by Smalley (1964) and Jones & Pilpel (1966a). They were more concerned with flow properties- rather than material properties- and did not observe any interesting interactions between gravitational and cohesive forces.

Some loessic relevance?  When loess material is falling from the sky to make a loess deposit the size of the particles is important. Say loess has a mode size around 30-50um, just on the cohesive side of that important reference point. The system is cohesive and this causes an open structure to form, limited compaction on deposition- some obviously but not enough to form a compact sediment. Had the particles been somewhat larger a much simpler packing would have been produced. 100um particles can move relative to each other. 50um particles form open structured systems with quite high tensile strengths, and the strength grows as some cementation occurs. Enough tensile strength to form high vertical faces in exposures, and to retain the open structure until loaded and wetted.

Friday, 6 February 2015

L.S.Berg (1876-1950)

L.S.Berg browsing in the Tin Drum Bookstore in Leicester [no - that's just wishful thinking]. L.S.Berg browsing in the stacks of the Library of the Zoological Institute in Leningrad [maybe].

L.S.Berg was born in 1876 so 2016 is the 140th anniversary of his birth- in Bendery(which is now in Transnistria or perhaps Moldova). His theory of loess formation was published in 1916 ; we have a convenient centenary: 100 years of Loessification.