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Leonard Horner in Bonn 1831–1833, finding loess and being incorporated into Lyell’s Loess Legion

Smalley Ian

Geologos

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2020

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Vol. 26, No. 2

163--170

EN

Leonard Horner (1785–1864) was a pioneer in the study of loess. His 1836 paper on the geology of Bonn contained detailed descriptions of loess in the Rhine valley. He identified and presented loess as an interesting material for geological study. He investigated loess in the crater of the Rodderberg with Charles Lyell in 1833. He presented the first significant paper on loess in Britain in 1833, but it was not published until 1836. With the assistance of G.A. Goldfuss and J.J. Noegerath he conducted early studies of the Siebengebirge and published the first geological map of the region, and the first picture of loess, at Rhondorf by the Drachenfels. He became the eleventh person to be included in the list of loess scholars which Charles Lyell published in volume 3 of the Principles of Geology. These were Leonhard, Bronn, Boue, Voltz, Steininger, Merian, Rozet, Hibbert in 1833, Noeggerath, von Meyer in 1835, Horner in 1837. Horner arrived after the publication of his studies on the loess at Bonn in 1836.

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Desert loess: a selection of relevant topics

Smalley Ian, Marshall John, Fitzsimmons Kathryn, Whalley W. Brian, Ngambi Samson

Geologos

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2019

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Vol. 25, No. 1

91--102

EN

In discussions on loess, two types are often demarcated: glacial loess and desert loess. The origin of the idea of desert loess appears to lie with V.A. Obruchev who observed wind-carried silt on the Potanin expedition to Central Asia in 1895. It might be considered that desert loess would be defined as loess associated with deserts but it came to be thought of as loess produced in deserts. This led to some controversy as no mechanism for producing silt particles in deserts was readily available. Bruce Butler in Australia in particular cast doubt on the existence of desert-made loess. Butler indicated loess-like deposits in Australia which he called Parna; these are very like loess but the silt sized particles are actually clay mineral agglomerates of silt size- formed in dry lake regions. At the heart of the desert loess discussion is the problem of producing loess material in deserts. It has been suggested that there are no realistic mechanisms for forming large amounts of loess dust but there is a possibility that sand grain impact may produce particle shattering and lead to the formation of quartz silt. This would appear to be a reasonable mechanism for the African deposits of desert loess, but possibly inadequate for the huge deposits in China and Central Asia. The desert loess in China and Central Asia is loess associated with a desert. The material is formed in cold, high country and carried by rivers to the vicinity of deserts. It progresses then from deserts to loess deposit. Adobe ground may be defined as desert loess. Adobe occurs on the fringe of deserts, notably in the Sahelian region of Africa, and in SW USA. The use of adobe in construction represents the major utilization of desert loess in a social context. More understanding of adobe is required, in particular with respect to the adobe reaction, the low order chemical reaction which provides modest cementitious properties, and can be likened to the pozzolanic reactions in hydrating cement systems. The location of loess and loess-like ground on the peripheries of deserts is aided by the observation of the nesting sites of bee-eater birds. These birds have a determined preference for loess ground to dig their nesting tunnels; the presence of nest tunnels suggests the occurrence of desert loess, in desert fringe regions. We seek amalgamation and contrast: ten main topics are considered: words and terms, particles, parna, geotechnical, adobe, people, birds, Africa, Central Asia, Mars. The aim is some large generalizations which will benefit all aspects of desert loess investigation.

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A man from Bendery: L.S. Berg as geographer and loess scholar

Smalley Ian, Markovic Slobodan, O’Hara-Dhand Ken, Wynn Peter

Geologos

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2010

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Vol. 16, No. 2

111-119

EN

Lev Semenovich Berg was born in Bendery, in Moldova. He had great success as an ichthyologist and geographer; he also proposed, in 1916, an interesting theory of loess formation. As a biologist he was persecuted by Lysenko and the Soviet state in the time of pseudo-science in the 1930s and 1940s. Despite his being persecuted, the loess theory became, in effect, the official Soviet theory of loess formation. This theory had to be compatible with his ‘landscape’ theory which did not find favour in Marxist-Leninist geography. Berg’s loess theory was very much a geographical theory, as opposed to the geological theory of aeolian deposition, which was accepted outside the Soviet Union.Berg was hugely successful in many fields, but his contributions to loess science tend to be neglected. His ‘soil’ theory of loess formation has been widely disparaged but still has some influence in Russia. The concept of loessification may still be relevant to the later stages of deposit formation; the slow transition from metastable to collapsible may be best described as loessification.