AluSiV - Aluminium and silicon in soils and the environment,

September 2008 – Report

Colin Farmer

The AluSiV meeting held from the 3^rd-5^th September 2008 at the Macaulay Institute, was conceived as a tribute to Colin Farmer (1920–2006) who, with the exception of a short period immediately after his retirement in 1983, spent all his working life at the Macaulay Institute in Aberdeen, Scotland.  Colin made major contributions to our understanding of the mineralogy and chemistry of aluminium and silicon in soils, as well as pioneering the use of infrared spectroscopy in the identification, characterization and reactivity of the amorphous or poorly crystalline secondary minerals involved. Under the name 'AluSiV' the Clay Minerals Group and the British Society of Soil Science endeavoured to bring together a conference that would be wide ranging from the nano- to the landscape scale; where interactions between chemistry, mineralogy and biology would be the link between these scales; and where the importance of cutting edge analytical methods would be apparent. 

Jim Russell, who was a close colleague of Colin’s over several decades, opened the meeting with a ‘A tribute to Victor Colin Farmer’ (a podcast of this tribute is available below).  Jim, described how the first IR spectrometer was obtained at the Macaulay in 1954 and how quickly Colin mastered the reading of  IR spectra and how his open-door approach led to many very successful collaborations.  

 Colin Farmer, Jim Russell,   Ian Black and Tony Fraser (kneeling) with a new infrared spectrometer. Circa 1970.

 He went on to describe how a paper with Bruce Mitchell in 1962 was the first lead into Colin’s pioneering work on imogolite and the importance of amorphous minerals in soils. 

The first scientific talk of the conference was the 8^th George Brown lecture presented by Roger Parfitt, of Landcare New Zealand on ‘Allophane and imogolite and their influence on biogeochemistry’.  Roger reviewed the formation, structure and properties of allophane and imogolite in soils and then went on to explore the interactions between these minerals from a biogeochemistry perspective in relation to carbon sequestration, the sorption of phosphorous,  and the interactions of allophane and imogolite with heavy metals and pathogens in soils.  This was followed by a lecture by Jon Petter Gustaffson, the first of four invited lectures.  Jon Petter spoke on ‘Aluminium and silicon solubility in forest soils – discussion of the relevant mechanisms’.  Jon Petter discussed the processes that control Al solubility including the role of imogolite-type material and the possible importance of processes such as Al adsorption onto Fe-oxides.  If was clear from this talk that there is still ample scope for collaboration between modellers and mineralogists to advance our understanding of natural processes.  Three talks on allophane and imogolite came next - staring with Simon Delattre who described a first principle study of imogolite;  Clement Levard then described a synthethic approach to the characterisation of both allophane and imogolite; and finally Abidin Zaenal described the results of a study to understand the structure and surface properties of allophane via ab initio calculations. This set of talks served to emphasise the continued and expanding interest in these natural nano-materials.  After some coffee the scale of observation increased to that of the landscape and Michael Sommer delivered a very thoughtful lecture on the process he terms lateral podzolization, documenting evidence for lateral transfer of material accompanying the better known vertical transfers associated with podzolization.  Transport of clay colloids and their association with heavy metals was the theme of the second talk in this session by Paola Adamo who documented and explained associations between colloids, clays, chromium and copper in soils from southern Italy, which have been polluted by the tanning industry.  The final session of the day began with a lecture by Amir Sandler who used a combination of peak decomposition and XRD pattern simulation programs to document increases in the K content of mixed-layer clays in soils from Israel, changes which he related to changes in rainfall and vegetation.  Bruno Lanson then described the XRD characterisation of artificially prepared hydroxy-interlayered vermiculite, showing how XRD methods can be used to obtain information on the nature of the structural mechanisms involved in the transformation of vermiculite to hydroxy-interlayered vermiculite.  This was followed by a talk by Jeff Wilson that described the differences in the forms of halloysite that may be encountered in soils, which he related to differences in weathering intensity and duration.  The halloysite theme was continued by Steve Hillier, who outlined an application of full-pattern fitting of XRD patterns to the quantification of halloysite in soils and rocks and the potential of the method to cope with mixtures containing both kaolinite and halloysite.  That completed the first day of talks and discussion was adjourned to the wine reception.

Day 2 was the field trip to examine podzolic soils in north-east Scotland and fortunately the weather was glorious sunshine and blue skies.  Following a brief coffee stop at  the Falls of Feugh, the coach pulled into the first locality at Glen Dye to examine a soil profile developed on glaciofluvial sands and gravels derived from granites and schists.  The second locality was further up the hill at Kircram.  From this site there are spectacular views of the 30 m high tor on the top of Clachnaben. The tor is known locally as the devil’s bite. Legend has it that the devil took a bite out of the hillside one night as he flew back from visiting the more Godless people in the south, but the land proved to be  too sour even for his taste and he spat it out. Another version has it that he spat the rock at his wife during a furious argument and thereby burying her under the tor. Modern day geologists will tell you that the tor is a residual feature probably developed due to mechanical disintegration of the granite during peri-glacial conditions and that the cleft is a meltwater channel.  The party stopped for lunch in the Clatterin Brig, and lunch was followed by a brief stop at the Macaulay Institute’s research farm at Glensaugh.  The final stop of the day at Candy farm in the Mearns was to examine a humus iron podzol developed in deep Old Red Sandstone Drift.

The conference dinner was held that evening at the Patio hotel and although the beer was expensive the organisers had ensured that there was plenty of wine.  Jeff Wilson was given a camera to look after and showed that he had clearly has missed his calling in life as a photographer as he enthusiastically snapped away at every table.  The conference was honoured to have Colin Farmer’s family represented by Colin’s wife Jane, his son George and George's wife Linda.   Following the meal, the Clay Minerals Group had a surprise to spring on long-serving member Derek Bain.  Derek is the only member of the Group who has held all four offices of Chairman, Secretary, Treasurer, and Principal Editor of Clay Minerals.  Derek was presented with a certificate to mark his election to Honorary Life Fellowship of the Mineralogical Society in recognition of his service to the Mineralogical Society and the Clay Minerals Group over many years.

Dr Derek Bain receiving Honorary Life Fellowship of the Mineralogical Society (presentation by Dr Steve Hillier, chairman of the Clay Minerals Group)

Day 3 was back to the talks and kicked off with a keynote presentation by Sabine Petit on the ‘Contribution of infrared spectroscopy to studies of clay minerals’ Sabine began by recounting how as a student she had encountered Colin Farmer at the International Clay Conference in 1989, but, having begun to read his book, she held him in so much awe that she was unable to summon up the courage to speak to him.  Torstein Seiffarth continued the infrared theme of the morning with a talk about Cu²⁺-and NH⁴⁺-exchanged montmorillonites from bentonites.  Following a brief coffee break the final keynote speaker, Jana Madejová, spoke about the ‘Possibilities of near-infrared spectroscopy in the investigation of reduced-charge smectites’. Before delivering her talk Jana also described how she had had the opportunity to talk with Colin when she had first  visited the Macaulay Institute 11 years previously and how her copy of his book on infrared spectroscopy is the only book she will never lend to anyone else.  The remainder of the morning session was also devoted to talks on infrared spectroscopy.  Georgios Chryssikos delivered a very clear lecture on the use of near infrared spectroscopy to derive the composition of palygorskite.  Peter Komadel came next, describing his work with Jana Madejová on iron in smectites as seen by infrared spectroscopy.

The final afternoon session was the antipodean session on iron and aluminium oxides.  Balwant Singh open the session with a detailed account of how in situ ATR-FTIR had been used to monitor P adsorption on goethite and the results fitted with surface complexation models and understood in terms of density functional theory calculations.  Matt Landers went next, describing the evidence for aluminium in goethite and hematite from Australian soils and their effects on the properties of these minerals.  The conference was rounded off with a presentation by Bob Gilkes on ‘Unexpected forms of aluminium in bauxite: a burning issue’.  Bob described how various oxides, such as corundum and hercynite normally associated with high temperatures are found in some Australian bauxites and how they probably record a history of bush fires.

AluSiV was a relatively small conference, conceived as a tribute to Colin Farmer.  Over the course of the three days discussion was lively, both in the lectures and in the field. We have no doubt that this was the kind of intimate and engaging conference that Colin would have thoroughly enjoyed.  Many thanks to all the delegates who took part, and for support from the Macaulay Institute, the British Society of Soil Science, and Bruker AXS.

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Photographic and audio records of the events of the conference