Sedgwick & Murchison: early observations on Loess in the Danube valley

Sedgwick, A., Murchison, R.I.  1832.  A sketch of the structure of the eastern Alps, with sections from the newer formations on the northern flanks of the chain, and through the Tertiary deposits of Styria etc. etc.   Transactions of the Geological Society of London (s2) 3, 301-420
with supplementary observations, sections, and a map by R.I.Murchison.

An enormous paper, and difficult to reference; we approach it via the writings of Horner and Lyell.
Horner (1836, p.460): " In the synopsis of the successive deposits in the basin of Vienna, given by Mr.Murchison, the uppermost is described to be 'Alluvial loam, called Loess, with terrestrial shells of existing species.. mixed with bones of elephants of extinct species. The average thickness of this deposit is about 60ft but at some places the thickness is much greater. Further, it is greatly expanded near Krems and St.Polten, reaching occasionally the thickness of 140ft, and having, near these places, the exact appearance of the old alluvial hillocks in the valley of the Rhine, which have been described by M.Voltz.." 
We appear to have early references to the loess in the Danube basin; in fact these might be among the earliest references to loess in the Danube basin..

Charles Lyell is in Europe in July 1835, he writes to Sedgwick: " I am reading you and Murchison on the Eastern Alps, as I am going so near your section. Your elaborate joint paper is now quite a treat. Boue has given me many Gosau fossils. He is going to live four years in Vienna, and next year to do the Balkan. My wife says, 'Give my kind regards to Mr.Sedgwick, and tell him it is dreadfully hot.'
Lyell deploys a well chosen phrase-'your elaborate joint paper; its impressive that he carried so much paper with him.  This elaborate joint paper appears to have been a bit neglected subsequently; no mention in the detailed history of Danube loess research by Markovic et al (2016)- not surprising, the material is well hidden but the 140ft thick loess at Krems deserves a mention.

The history of Danube loess research 2016.  Markovic, S.B., Fitzsimmons, K.E., Sprafke, T., Gavrilovic, D., Smalley, I.J., Jovic, V., Svircev, Z., Gavrilov, M.B., Beslin, M.  Quaternary International 399, 76-89.

Zalasiewicz on Geology

Jan Zalasiewicz  2018.  Geology: A Very Short Introduction.  Oxford University Press 145p.

JZ presents the story of geology in the compact format of the 'Very Short Introduction' series by OUP.  There are over 550 titles in the VSI series and 'Geology' is a welcome addition.

Earth history from the very beginning to the Anthropocene- neatly illustrated; -and properly indexed. Go to L in the index, look for Loess- we have an entry- p.83. We will have to quote- the temptation is too great:
"These are still widely called 'drift' deposits (from the old idea that many formed from drifting icebergs), but are more technically referred to as 'superficial' or 'surficial' deposits. Not all relate to glaciation, by any means. In low latitude parts of the world they can include thick windblown sand deposits, as in parts of the Sahara, or the thick windblown silt or loess that covers much of Central China, having been blown there during the past two and a half million years from the Himalayas, and peat bog deposits. Where large rivers such as the Mississippi or Ganges-Brahmaputra meet the sea, huge deltas build out. "
Good to see the Himalayas acknowledged as the source of loess material; and two and a half million years of loess deposition. Is Central China the place or would the loess region be better described as northern China? and where do the peat bog deposits contribute? 

Another relevant VSI book is The Ice Age by Jamie Woodward:
Jamie Woodward 2014.  The Ice Age: A Very Short Introduction.  Oxford University Press 163p.

This is in many ways an excellent study of Quaternary matters- but there is one terrible short-coming.
Look in the index, go to L- where is Loess?  Why does JW not mention loess? surely Loess is one of the most interesting and significant of the Ice Age deposits.

Adobe as Loess (Why not?)

Alfred Scheidig (1934) in his classic book 'Der Loess und seine geotechnischen Eigenschaften' stated that:  In addition to the aforementioned loesses, which are mainly of glacial origin, there are continental loesses in the fringe regions around desert and steppe zones. Keilhack (1920) mentions this in Texas, Shaler (1899) in Montana, Henning (1911) in Colorado, New Mexico and Arizona. In the latter two areas, the loess is closely related to the formation known as 'adobe' (pronounced adobi) in fact, in most cases it is identical to adobe (translated by LL).

Adobe is widely used as a building material in Africa- in and around the 15N region; it is also used in the S.W.USA; these are probably the best known adobe regions. The sources of adobe material in Africa can perhaps be demarcated.

On the map <<<  FJ is the Fonta-Djalon highlands; BD is the Bodele depression; EH is the Ethiopian highlands. Also indicated- the catchment of the River Niger.  The highlands can be seen as particle-source regions- possibly for loess sized particles. The Bodele depression is the classic source region for small dust particles- derived from deposits in ancient Lake Chad. This can deliver clay-mineral material and silica diatoms. A lot of interesting particulate material is available in the 15N region. For the adobe reaction to function effectively there needs to be some carbonates in the system. The Ethiopian Highlands deliver large amounts of silt-sized material for the Nile Valley deposits and also makes material available for the eastern parts of the adobe region. There are actually few well defined loess deposits in Africa- but there must be a large amount of usable material in accessible regions.

 

Onn Crouvi and associates have provided a neat map of Africa showing loess deposits and the critical regions. The countries of Mauritania, Mali, Niger and Chad cover much of this region; classic adobe buildings are found in this zone.

Crouvi, O., Amit, R., Enzel, Y., Gillespie, A.Ar. 2010.  Active sand seas and the formation of desert loess.  Quaternary Science Reviews 29, 2087-2098.

 

Brickmakers at Mohenjo Daro

Bricks are ubiquitous at Mohenjo Daro and Harappa. Bricks were important in the Indus Valley settlements. The ancient Chinese society left us many objects and much writing; the ancient Egyptians left us an entire academic discipline; the Indus Valley people mostly left us bricks.

Very few artefacts- most famously the bronze statuette of the young woman dancer and the 'Priest/King' stone bust; but very many bricks- good quality fired bricks in enormous numbers. Can we study the Indus Valley people more closely via their bricks? Can we mobilize brick specialists to tell us more?- via a study of bricks.
We propose that these were loess bricks. Loess is known as excellent brickearth; the positioning of the loess deposits may have influenced the location of the brick built cities. Great brick buildings extend beyond Hampton Court Palace and St.Pancras station, they include the city structures at Mohenjo Daro and Harappa. The loess deposits in Kent & Essex supplied the bricks for Victorian London; the Indus Valley loess supplied the bricks for Mohenjo Daro.

The bricks at Harappa were discovered before the city (can we say that?). When the Lahore -Karachi railway was being constructed in 1856 the constructors discovered large deposits of hard, strong bricks which they used to construct the trackbed foundations for many miles of track (about 100 miles). These four thousand year old bricks provided excellent ballast material. The old Harappans made amazingly good bricks- possibly because they had the best available brickearth. Perhaps the brickmakers were important people in Indus Valley societies; perhaps the priest/king is really a brickmaker.

Figures from:
J.M.Kenoyer 1991. The Indus Valley traditions of Pakistan and western India. Journal of World Prehistory 5 (4)  331-385