SoS RARE

Lead Research Organisation: University of Brighton
Department Name: Sch of Environment and Technology

Abstract

Rare earth elements (REE) are the headline of the critical metals security of supply agenda. All the REE were defined as critical by the European Union in 2010, and in subsequent analysis in 2014. Similar projects in the UK and USA have highlighted 'heavy' REE (HREE - europium through to lutetium) as the metals most likely to be at risk of supply disruption and in short supply in the near future. The REE are ubiquitous within modern technologies, including computers and low energy lighting, energy storage devices, large wind turbines and smart materials, making their supply vital to UK society. The challenge is to develop new environmentally friendly and economically viable, neodymium (Nd) and HREE deposits so that use of REE in new and green technologies can continue to expand.
The principal aims of this project are to understand the mobility and concentration of Nd and HREE in natural systems and to investigate new processes that will lower the environmental impact of REE extraction and recovery.
By concentrating on the critical REE, the research will be wide ranging in the deposits and processing techniques considered. It gives NERC and the UK a world-leading research consortium on critical REE, concentrating on deposit types identified in the catalyst phase as most likely to have low environmental impact, and on research that bridges the two goals of the SoS programme.
The project brings together two groups from the preceding catalyst projects (GEM-CRE, MM-FREE) to form a new interdisciplinary team, including the UK's leading experts in REE geology and metallurgy, together with materials science, high/low temperature fluid geochemistry, computational simulation/mineral physics, geomicrobiology and bioprocessing. The team brings substantial background IP and the key skills required. The research responds to the needs of industry partners and involves substantive international collaboration as well as a wider international and UK network across the REE value chain.
The work programme has two strands. The first centres on conventional deposits, which comprise all of the REE mines outside China and the majority of active exploration and development projects. The aim is to make a step change in the understanding of the mobility of REE in these natural deposits via mineralogical analysis, experiments and computational simulation. Then, based on this research, the aim is to optimise the most relevant extraction methods. The second strand looks to the future to develop a sustainable new method of REE extraction. The focus will be the ion adsorption deposits, which could be exploited with the lowest environmental impact of any of the main ore types using a well-controlled in-situ leaching operation.

Impact will be immediate through our industry partners engaged in REE exploration and development projects, who will gain improved deposit models and better and more efficient, and therefore more environmentally friendly, extraction techniques. There will be wider benefits for researchers in other international teams and companies as we publish our results. Security of REE supply is a major international issue and the challenges tackled in this research will be relevant to practically all REE deposits. Despite the UK not having world class REE deposits itself, the economy is reliant on REE (e.g. the functional materials and devices industry is worth ~£3 Bn p.a.) and therefore the UK must lead research into the extraction process. Manufacturers who use REE will also benefit from the research by receiving up to date information on prospects for future Nd and HREE supply. This will help plan their longer term product development, as well as shorter term purchasing strategy. Likewise, the results will be useful to inform national and European level policy and to interest, entertain and educate the wider community about the natural characters and importance of the REE.

Planned Impact

SoS RARE research will have an immediate economic impact by improving the prospects for the security of supply of neodymium (Nd) and the key heavy rare earth elements (HREE). The proposal has engaged six core industry partners involved in the exploration and development of new REE mines who will benefit immediately by introduction of our new exploration models and improved techniques for mineral extraction. Processing of REE raw materials is currently a major bottle neck in the value chain, and development of better methods will have an immediate impact on REE supply concerns. This will make projects more economically viable and environmentally friendly, helping to ensure a more stable supply. The four consultant company partners will gain key expertise and experience in exploration and processing which they will spread out into the wider REE mining and processing industries.

The unstable supply and cost of REE remains a major issue for manufacturers that make up a substantial part of the UK economy. A more secure supply chain will allow these manufacturers to better plan their short and long term product development. The research team will provide information on primary supplies, the likely development of future mines and how the supply chain will develop.
REE supply is a global concern. The project will have a global reach, through the industry partners involved (based in and working in the UK, Greenland, Malawi, Namibia, Spain, Canada and Australia), the core research collaborators in Germany, USA, Canada, Brazil and South Africa and wider international network links to Japan, France, and Madagascar. Diversity of supply is the key. This research proposal will place the UK as a centre in REE expertise and at the forefront of critical metals development.

The critical metals issue is requiring changes in UK Government and European Union policy, including increased support for research on primary supplies, recycling of existing metal stocks and substitution. The impact of this research on the prospects for low environmental impact extraction of REE, diversity/security of supply and responsible sourcing will be directly relevant to future policy. The 'race' to engineer REE out of new technologies will be unnecessary and many new applications could be explored. Therefore major impact will occur at the policy level as the research guides the decision making in research funding and legislation for REE.

Few people had even heard of 'rare earths' until the issue of China restricting supply reached the news headlines in 2010, yet this family of elements are ubiquitous in digital and green technologies, from the slimmest mobile phones to giant wind turbines. We will exploit the realisation among the general public of the importance of REE towards their modern high technology life-style and demonstrate the importance of REE chemistry and geology. The REE are extremely interesting and ideal for creative and educational outputs to entertain and inform wider non-technical audiences. Encouraging the public, including school students, to learn more about REE in nature is a key part of our outreach programme.

Publications

10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
NE/M011267/1 01/05/2015 31/12/2019
1648135 Studentship NE/M011267/1 01/10/2015 31/03/2019 Eva Marquis
 
Description A key part of the SOS:Rare project was to investigate the potential for Ion Adsorption Deposits (IAD) to be a source of the rare earth elements (REE) out side of China, where they are a major sources, particularly of the heavy REE. IADs are developed in weathered rock, where the REE can be easily leached from clay-rich soil zones in tropical soils (laterites). The project aimed to demonstrate that deposits of the same type could generate globally, and that laterites developed by weathering rock that was already REE-rich would be a potential resource. Investigation of laterites from Madagascar demonstrated that REE did occur in easily leachable form, and that the distribution of the REE in laterite was controlled by the original rock, topographic variations and permeability variations which control the flow of groundwater during weathering. Samples from Madagascar were compared with samples from China using Synchrotron X-ray absorption spectroscopy. This showed that the REE were adsorbed to kaolinite clay as hydrated ions, and not as chemically bound mineral species. Although this has been widely suggested it had never been directly demonstrated before. It has implications for the design of more environmentally sensitive extraction techniques.
Exploitation Route Identification of precise mineralogical site of the REE in ion adsorption deposits from China and Madagascar demonstrates that the same mechanism of resource formation can operate globally. The data can now be used for global comaprisons to demonstrate the presence of ion adsortpion deposits, and to inform improve processing strategies to extract the REE.
Sectors Energy,Environment,Other

URL https://www2.bgs.ac.uk/SoSRARE/
 
Description The results of the study have been publicised by Physics Today, promoting the results to the scientific community and general public. On the basis of work conducted an industry project was carried out in Jamaica to investigate REE resource potential there. A contract has now been signed for a second industry project investigating REE resource potential in weather rock in Kazakhstan.
First Year Of Impact 2021
Sector Environment,Other
Impact Types Economic

 
Description Bedrock preconditions and environmental factors in the formation of ion adsorption REE
Amount £74,200 (GBP)
Funding ID IP-1693-1116 
Organisation Natural Environment Research Council 
Department NERC Isotope Geosciences Laboratory
Sector Academic/University
Country United Kingdom
Start 12/2016 
 
Description Weathering of carbonatite REE deposits (WREED): a critical stage in generation of critical metal resources.
Amount £80,410 (GBP)
Funding ID NE/V008935/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 08/2021 
End 03/2022
 
Description Memorandum of understandign with the Univeristy of Antanarivo 
Organisation University of Antananarivo
Country Madagascar 
Sector Academic/University 
PI Contribution Agreement to cover joint fieldwork in Madagascar and to facilitate relationships with Malagasy government.
Collaborator Contribution Joint fieldwork in the Ambohimirahavy and Manongarivo areas. Sampling laterite profiles for material characterisation and column experiments. Sampling bedrock for petrological study.
Impact Joint fieldwork.
Start Year 2016
 
Description A talk at the Hi Tech Alk Carb/SOS:rare joint workshop titled 'Concentrating REE in the weathering zone: the ion adsorption clays' by M. Smith. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A presentation at a joint workshop on NERC/EU funded critical REE research attended by academics, policy makers and industry representatives.
Year(s) Of Engagement Activity 2019
URL https://www.bgs.ac.uk/hiTechAlkCarb/downloads/CriticalRawMaterialsFuture_Nov19_programme_v2.pdf
 
Description A talk at the Hi Tech Alk Carb/SOS:rare joint workshop titled 'The Role of Hydrothermal Processes In Carbonatite-Related REE Deposits' by M. Smith. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation a joint workshop between NERC and EU funded projects on critical REE deposits to an international audience of academics, industry representatives and policy makers.
Year(s) Of Engagement Activity 2019
URL https://www.bgs.ac.uk/hiTechAlkCarb/downloads/CriticalRawMaterialsFuture_Nov19_programme_v2.pdf
 
Description A talk at the SGA meeting, Glasgow, titled 'Late- to post-magmatic controls on rare earth element mineralogy and the potential influence on subsequent ion adsorption ores' by E. Marquis 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation at SGA meeting Glasgow, in session on Mineral Resources for Green Growth, with an audience of ~100.
Year(s) Of Engagement Activity 2019
URL https://www.sga2019glasgow.com/abstract
 
Description A talk at the SGA meeting, Glasgow, titled 'Mechnaisms for the generation of HREE mineralisation in carbonatites: Evidence from Huanglongpu, China' by M. Smith 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation at the SGA meeting, Glasgow in the session Mineral Resources for Green growth. Highlighted project results to practitioners and industry. Audience of ~100.
Year(s) Of Engagement Activity 2019
URL https://www.sga2019glasgow.com/abstract
 
Description A talk at the SGA meeting, Glasgow, titled 'Resolving the structural state of heavy rare earth elements in lateritic ion adsorption clays' by A. Borst. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation at the SGA 2020 meeting in Glasgow to an audience of approximately 100 academics and industry representatives.
Year(s) Of Engagement Activity 2019
URL https://www.sga2019glasgow.com/abstract
 
Description Article in Physics Today 'New Sources for rare metals vital in modern technology'. 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Article in Physics Today 'New Sources for rare metals vital in modern technology' summarising the work of SOS:Rare and in particular the paper in Nature Communications arising from this project dealing with REE adsorption on to clays.
Year(s) Of Engagement Activity 2020
URL https://phys.org/news/2020-09-sources-rare-metals-vital-modern.html
 
Description Conference presentation at EGU 2017 on HREE enrichment in carbonatites 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Conference poresentation at EGU 2017. Abstract: Origin of heavy REE mineralisation in carbonatites: Constraints form the Huanglongpu Mo-HREE deposit, Qinling, China.
Martin Smith1, Cheng Xu2, Jindrich Kynicky3, Delia Cangelosi4, Wenlei Song1
1School of Environment and Technology, University of Brighton, Brighton. UK.
2Institute of Earth and Space Sciences, Beijing, China.
3Mendel University, Brno, Czech Republic.
4University of Leeds, Leeds, UK.
The carbonatite dykes of the Huanglongpu area, Lesser Qinling, China, are unusual in that they are quartz-bearing, Mo-mineralised and enriched in the heavy rare earth elements (HREE) relative to typical carbonatites. Carbonatite monazite (208.9±4.6 Ma to 213.6±4.0; Song et al., 2016) gives a comparable U-Pb radiometric age to molybdenite (220Ma; Stein et al., 1997), confirming interpretations that Mo is derived from the carbonatite, and not a subsequent overprint from regional porphyry-style mineralisation (~141Ma). The sulphides in the carbonatites have mantle-like d34S (~1‰) and low d26Mg values (-1.89 to -1.07‰), similar to sedimentary carbonates, suggesting a recycled sediment contribution in their mantle sources that may be responsible for the Mo and HREE enrichment (Song et al., 2016). The textures of REE minerals indicate crystallisation of monazite-(Ce), bastnäsite-(Ce), parisite-(Ce) and aeschynite-(Ce) as magmatic phases. Monazite-(Ce) was subsequently altered to produce apatite, which was in turn replaced by britholite-(Ce), accompanied by the formation of allanite-(Ce). The REE-fluorcarbonates where replaced by synchysite-(Ce) and röntgenite-(Ce). Aeschynite-(Ce) was altered initially to uranopyrochlore and then pyrochlore with uraninite inclusions. The mineralogical evolution reflects the evolution from magmatic carbonatite, through to more silica-rich conditions during the magmatic-hydrothermal transition, to fully hydrothermal conditions accompanied by the formation of sulphate minerals. Each alteration stage resulted in the preferential leaching of the LREE and enrichment in the HREE. Mass balance considerations indicate that the HREE enrichment could not be a passive process, and that hydrothermal fluids must have contributed HREE to the system. The evolution of the fluorcarbonate mineral assemblage requires an increase in aCa2+ and aCO32- in the metasomatic fluid, and so breakdown of HREE-enriched calcite may have been the HREE source. Solubility products are lower for LREE minerals compared to HREE minerals, so leaching in the presence of strong, LREE-selective ligands (Cl-, CO32-) may account for the depletion in late stage minerals in the LREE, but cannot account for subsequent preferential HREE addition. Fluid inclusion data indicate the presence of sulphate-rich brines during late stage alteration, and hence sulphate complexation may have been important for preferential HREE transport, as sulphate has been shown to be non-LREE selective during the formation of complex ions. The combination of mantle source with a recycled oceanic sediment component, and REE enrichment during magmatic processes, and late stage alteration with non-LREE selective ligands such as sulphate may be critical in forming HREE-enriched carbonatites.
Song et al., (2016) Origin of unusual HREE-Mo-rich carbonatites in the Qinling orogen, China. Scientific Reports, 6:37377 | DOI: 10.1038/srep37377.
Stein et al. (1997) Highly precise and accurate Re-Os ages for molybdenite from the East Qinling-Dabie molybdenum belt, Shaanxi province, China. Econ. Geol. 92, 827-835 (1997)
Year(s) Of Engagement Activity 2018
 
Description Conference presentation at ERES 2017 on Ion Adsorption Deposits in madagascar 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Formation of Ion-adsorption deposits: A new example of REE mineralised regolith in the Ambohimirahavavy Complex, Madagascar.
Guillaume ESTRADE, Eva MARQUIS, Peter NASON, Kathryn GOODENOUGH and Martin SMITH
1 Géosciences Environnement Toulouse, Université Toulouse III Paul Sabatier, Toulouse, F
2 School of Environment and Technology, University of Brighton, Lewes Road, Brighton, UK
3 British Geological Survey, the Lyell Centre, Research Avenue South, Edinburgh, UK
Guillaume.estrade@get.omp.eu
Ion adsorption-type deposits (IADs) are rare earth elements (REE) deposits typically formed under sub-tropical climates from the weathering of igneous rocks, which contain primary and/or secondary REE-minerals. In these deposits, the REE are mainly adsorbed onto the surface of clays (kaolinite and halloysite) but also contained in the structures of secondary minerals1. These deposits are low grade, ranging from 300 to 3500 ppm total rare earth oxides, and generally smaller than other REE deposits (0.5 to 0.01 Mt), but have a high proportion of the most valuable heavy REE2 (HREE). The REE are easily released by low cost ion-exchangeable processes, either by in situ leaching or heap leaching with acid electrolyte solutions. Most of these deposits are currently mined in Southern China, but recently discovered potential IADs are under exploration in South America, Africa, and Southeast Asia.
Although it is known that most of the releasable REE are adsorbed onto the surface of clays, the processes of formation of these deposits are poorly known. Recently, secondary phosphates have been documented in a regolith overlying a granite in northern Vietnam3. Identification of other REE-carriers could help to adapt the procedures of extraction. In this study, we assess a potentially new IAD from north-west Madagascar, and compare the data with currently exploited IADs in China. The mineralized lateritic regolith is derived from the weathering of alkaline igneous rocks from the Ambohimirahavavy alkaline complex. Representative natural and core profiles have been selected over the complex for a detailed mineralogical study associated with a five steps sequential extraction with the aim of better identifying the REE-bearing phases. Although no reference material is presently available to validate the extraction of REE, we used a sediment certified reference material BCR-701 with certified extractable concentration of Cd, Cr, Cu, Ni, Pb, and Zn.
X-ray diffraction and infrared spectroscopy show that kaolinite, together with halloysite, are the main types of clay in the Ambohimirahavavy regolith. Extraction with ammonium sulphate (pH=4, removes weakly adsorbed metals retained on thesolid surface and dissolves carbonates) shows that, in the different profiles and along a same profile, the leachable REE content is heterogeneous, ranging from 100 to 800 ppm total REE (TREE), with 10 to 20% HREE. Similar TREE concentrations are released from Chinese profiles but HREE proportion are twice higher than in Ambohimirahavavy profiles (100 to 1100 ppm TREE, 15 to 45% HREE). Leaching with magnesium chloride (pH=6, removes only weakly adsorbed REE) releases similar TREE concentration, suggesting that most of the leachable REE are adsorbed onto mineral surfaces. The REE recovery rate from ammonium sulphate leaching decreases continuously from La to Lu, except from Ce that is mainly released during the reducible leaching step with hydroxylammonium chloride (removes metals in Fe-Mn oxides and oxyhydroxides). Best TREE recovery (up to 60-70%) are localized at the pedolith/saprolith, and saprolith/saprock contacts.
Year(s) Of Engagement Activity 2017
 
Description Enrichment talk to Colliers 6th form College, Horsham. 25/11/2022 - The rare earth elements as critical metals: minerals resources for the low carbon transition. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact An enrichment talk presented to geography, geology and environmental science students, with a discussion afterwards particularly focussed on environmental issues relating to REE extraction.
Year(s) Of Engagement Activity 2022
 
Description Inaurgral lecture by Professor Martin Smith: Minerals, Metals and Microbes. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Inaugural public lecture following appointment of M. Smith to personal chair in geochemistry. Covered a range of material but a focus on SOS:Rare poutcomes for approximately 60% of the 1 hour lecture. Audience of general public, post graduate and under graduate students, industry professionals and academics.
Year(s) Of Engagement Activity 2019
URL https://www.brighton.ac.uk/research-and-enterprise/research-news/films-and-publications/inaugural-le...
 
Description Invited PGR student workshop, China University of Geosciences - 'Secondary processes in the origin of REE deposits' 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact A presentation and question and answer session on recent research on hydrothermal, metamorphic and weathering processes in the generation of REE deposits delivered to a large cohort of PhD students. ~50 students from the China University of Geosciences attended. Detailed questions and discussion with students working in the area as follow upto the meeting. New collaboration with Kun-Feng Qiu, CUG, Beijing discussed.
Year(s) Of Engagement Activity 2022
 
Description Invited seminar, University College London - The rare earth elements as critical metals: minerals resources for the low carbon transition. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact An invited seminar to BSc, MSc and PhD students at University College London as part of a course on Global Management of Natural Resources. Follow up questions and discussions with students.
Year(s) Of Engagement Activity 2023
 
Description PhD student conference presentation - Ion Adsorption-Type REE Deposit associated with the Ambohimirahavavy Alkaline Complex: Potential Controls on Mineralisation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Conference presentation at nation meeting (MDSG AGM) by PhD student Eva Marquis.

Abstract:
The Rare Earth Elements (REE: La-Lu) have been highlighted as 'critical materials' as a result of concerns over the security of supply. In particular demand for heavy REE (HREE: Gd-Lu) has increased over the past decade. Ion Adsorption-Type Deposits (IADs) supply the majority of HREE and yttrium to the global market. Containing more than c. 50% ion exchangeable REE (+ yttrium), typically adsorbed to the surface of clay minerals such as kaolinite and halloysite, it is the ease of extraction through leaching that makes IADs economically viable. Economic ion adsorption-type deposits are almost exclusively confined to areas of southern China underlain by metaluminous to weakly peraluminous granites. Notably the most HREE-enriched IADs in China are associated with HREE-enriched muscovite granites that contain easily degradable REE-minerals (e.g. fluorcarbonates) formed during deuteric alteration. The primary control on the formation of HREE-rich ion adsorption type deposits seems to be the presence of easily weathered HREE-bearing minerals in the protoliths, but there has been limited study of how these minerals form. Other than IADs, peralkaline igneous rocks are known to be a substantial source of REE, especially the valuable HREE but processing the 'hard-rock' deposits can be challenging. At Ambohimirahavavy, Madagascar, peralkaline igneous rocks have been weathered to form an ion adsorption deposit which is thus relatively easy to process.

The Ambohimirahavavy prospect is currently unique in hosting a recognised ion adsorption-type deposit developed above alkaline to peralkaline igneous and volcanic rocks, some of which carry REE mineralisation of up to 2.24% TREO. The ion adsorption ores are present within lateritic weathering profiles above these protoliths, and carry an average grade of 835 ppm TREO5. By studying this deposit we aim to understand better the preconditions necessary for the formation of IADs. Preliminary results from leaching experiments on variably mineralised weathered profiles from across the prospect demonstrate that bedrock variations are important in controlling the location of REE mineralisation. This is also evident locally within some laterite profiles, with differences in ion-exchangeable REE content being associated with recognisable changes in protolith composition (e.g. Profile TAND044: weathered pegmatite 738 ppm REE; weathered mudstone 378 ppm REE). Preliminary work has clearly identified the presence of clay sorbed REE above bedrock pegmatite and hydrothermal vein hosted mineralisation. Petrographic observations have shown the bedrock mineralisation to include late magmatic REE-bearing phases (eudialyte, zircon, pyrochlore) and hydrothermal phases (allanite, REE-fluorcarbonates) that could be easily broken down by weathering. Initial observations suggest that the development of the magmatic, and post-magmatic hydrothermal system may have been critical in the formation of an economic deposit by weathering.
Year(s) Of Engagement Activity 2017
 
Description PhD student presentation - Rare Earth Element mobility during the genesis and evolution of Ion Adsorption Deposits associated with Alkali Granitoid Complexes 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Study participants or study members
Results and Impact PhD student presentation at project progress meeting.
Year(s) Of Engagement Activity 2016
 
Description Poster at MDSG 2020 - REE adsorption experiments onto kaolintie with different ligands: Implications on ion adsorption REE deposit formation. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Post presentation at Mineral Deposits Studies Group AGM, Natural History Museum, London. Approximately 200 attendees. Further discussion with 20-30 attendees at post session.
Year(s) Of Engagement Activity 2020
URL https://www.minersoc.org/mdsg-2020.html
 
Description Presentation EU project expert panel (HiTech AlkCarb): The role of deposit architecture in subsolidus REE deposits, and the role of subsolidus processes in deposit architecture. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation as expert panel member on outcomes of SOS:Rare research to the EU HiTech AlkCarb project. Title: The role of deposit architecture in subsolidus REE deposits, and the role of subsolidus processes in deposit architecture. Abstract: Large deposits of the REE without hydrothermal influence are almost unknown, and evidence strongly suggests that sub-solidus alteration is critical in generating the highest grades in any particular mineralising system, and is responsible for modifying the overall REE distribution of mineralisation, sometimes to produce enrichments in more economically interesting elements. The structure and chemical behaviour of systems from the magmatic-hydrothermal transition to the weathering stage are therefore a critical element that must be incorporated in to deposit geomodels.
The localisation of fractures amenable to late magmatic dyke sill and vein formation is driven by fluid over pressure and decompression cycles, cooling and contraction and tectonic stress fields. The former can be seen in the Khan Bogd alkali granite intrusion, whilst latter is typical of carbo-hydrothermal vein-dyke systems at Huanglongpu, China. Coupled with fractional crystallisation, decompression can drive cycles of fluid immiscibility which can further concentrate rare metals, and lead to the generation of the first hydrothermal fluids. In alkaline and particularly carbonatite systems the range of late stage hydrated salt melts that can generated by this mechanism is large and includes alkali carbonate, chloride, fluoride and sulphate magmas and brines. At LugiinGol, Mongolia, this is exemplified by carbonate-fluoride veins, associated with REE fluorcarbonates, with textures indicative of separation of a mixed carbonate-fluoride melt from silicate magma, and possibly of the separation of an additional fluoride melt phase.
The potential for the generation of brines with a range of dominant ligands, in addition to the potential role of externally derived brines, influences the role of hydrothermal processes in mobilising, concentrating and fractionating the REE. At Huanglongpu the involvement of sulphate/rich post-magmatic brines, alongside cooling of the hydrothermal system, has resulted in the relative enrichment of the HREE at every stage of metasomatism. At Bayan Obo the role of chloride-rich aqueous carbonic brines was critical in cycles of LREE enrichment, with subsequent enrichment in and relative to La arising from cooling if the system and interaction with externally derived fluids during metamorphism. The original distribution of deposit intrusive and alteration fancies can also be identified at Bayan Obo by comparison with more recent deposits.
The bedrock architecture of alkaline complexes can also be a critical influence on grade distribution in ion adsorption REE deposits. At Ambohimirahavy, Madagascar, the REE are hosted in laterites developed above alkaline pegmatites. The distribution of the REE in this instance has a first order control from the distribution of eudialyte and pyrochlore mineralised pegmatites and associated allanite mineralised veins intruded into mud rock, and secondary order control from the geomorphology and hydrology of the recent to modern weathering system.
The case studies mentioned above are indicative of the control of alkali igneous complex architecture on the distribution of hydrothermal REE mineralisation, and highlight some areas in need of further study. They also show the control on REE distribution extends into secondary environments, and the associated geomodels have important potential application across a wide range of the geosphere.
Year(s) Of Engagement Activity 2018
 
Description Presentation at EGU 2017 on Ion Adsorption REE deposits 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation at the EGU conference, Vienna, abstract: REE concentration processes in ion adsorption deposits: Evidence from Madagascar and China.
Martin Smith1, Guillaume Estrade1,2, Eva Marquis1, Kathryn Goodenough3, Peter Nason1, Cheng Xu4, Jindrich Kynicky5,
1School of Environment and Technology, University of Brighton, Brighton. UK.
2 Université de Toulouse III, Toulouse, France.
3British Geological Survey, The Lyell Centre, Edinburgh, UK.
4Institute of Earth and Space Sciences, Beijing, China.
5Mendel University, Brno, Czech Republic.
Lateritic clay deposits, where the rare earth elements (REE) occur adsorbed to clay mineral surfaces, are currently the world's dominant supply of heavy REE (Gd-Lu). These deposits are currently only mined in China where there is a reported heavy REE enrichment, but other deposits are currently under exploration in Brazil, the Philippines and Madagascar. Concentration of REE within IADs has been proposed to be a dominantly supergene process, where easily degradable REE-minerals (e.g. REE-fluorcarbonates) break down and release REE that are then adsorbed to clay minerals. Here we present data from the Ambohimirahavavy Complex, Madagascar, and compare them to data from mineralised profiles in China, with the aim of further constraining the formation and REE enrichment processes in ion adsorption deposits. Bulk rock total REE contents from Madagascar vary from 400-5000ppm, with the HREE varying from 10 to 20% of the TREE. Ammonium Sulphate leaches (designed to remove clay-adsorbed REE) of laterite show leachable TREE from 130-500ppm, with no preferential HREE adsorption. Within the sequential extraction procedure the reducible fraction (hydroxylammonium chloride leach) showed the highest REE, but this is largely attributable to Ce4+ in oxide layers. Analysis of laterite profiles show that the REE distribution is heterogeneous, with control from both bedrock heterogeneity, and the hydrological variation between pedolith and saprolith. Similar patterns are seen in Chinese profiles from Jiangxi province. X-ray diffraction shows the clay fraction in all sites is dominated by kaolinite and halloysite. These data are consistent with experimental data which show that kaolinite is only HREE selective in high ionic strength solutions (Coppin et al., 2002), and suggest that HREE enrichment in lateritic deposits may be a function of exceptional bed rock conditions. Petrographic investigation of the Zhaibei granite, immediately underlying HREE enriched weathering profiles in Jiangxi province has identified the presence of HREE-enriched secondary phases associated with carbonate-rich areas (Xu et al., In press). Neodymium isotope data from primary granitic minerals (eNd(t)=-11.5±0.5) contrasts dramatically with data from HREE-enriched minerals (eNd(t)=0.9±0.8) indicating that pre-weathering metasomatism from fluids derived from outside the granite system may be critical in the HREE enrichment process of mineralised laterites.
Coppin et al. (2002) Sorption of lanthanides on smectite and kaolinite. Chem. Geol. 182, 57-68
Xu et al., (In press) Origin of heavy rare earth mineralization in South China. Nature Comms.
Year(s) Of Engagement Activity 2017
 
Description Presentation at Goldschmidt Conference 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster presentation:REE enrichment processes in the Ambohimirahavavy Complex ion adsorption deposit, Madagascar using Y-Nd µ-XANES Spectroscopy
P.A. NASON,M. SMITH, A. FINCH, A. BORST, G. ESTRADE, E.MARQUIS: Conventional lateritic ion adsorption deposits (IADs) hosting heavy rare earth elements (HREE) are currently only mined in China. A globally increased demand for these elements (Gd-Lu) has led to increased exploration outside of China. The Ambohimirahavavy Complex in Madagascar is currently in the advanced stages of mineral exploration and consists of an IAD which has formed by intense tropical weathering of peralkaline granite, pegmatitic dykes and a syenite ring, forming supergene enrichment in the form of a deep (1-30 m) lateritic clay deposit. REE contents vary from 400-5000 ppm, with HREE varying from 10 to 20 % of the Total-REE. Here we present data from four drill cores obtained in 2015, with the aims of delineating the REE enrichment processes from the primary bedrock to the IADs. XRD and SEM indicate kaolinite to be the predominant clay mineral hosting the REE, but that there are also correlations between REE concentrations and relic minerals such as Zircon and REE-fluorcarbonates in the lateritic protoliths. µ-XANES spectroscopy was utilised as a tool for evaluating REE coordination onto kaolinite and the relic minerals. Sythetic standards were used to provide a proxy of coordination states of Y and Nd to kaolinite, REE-fluorcarbonates and zircon. The XANES of Y and Nd associated with the kaolinite were found to be closely comparable to those of the REE-fluorcarbonates, notably parisite, indicating that the REE have similar coordination states. The REE in parisite is in a low point-symmetry 9 coordinate site. We infer similar coordination for Y and Nd. Preliminary interpretation of these data suggests that Y and Nd are present as 8-9 coordinated, hydrated, outer-sphere, basal surface complexes, rather than 5 or 6 coordinated edge complexes, or 6 or 8 coordinated interlayer complexes.
Year(s) Of Engagement Activity 2017
 
Description Presentation at the Resourcing Future generations meeting, Vancouver, Canada (RFG2018). 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A conference presentation titled:

Marquis, E., Goodenough, K., Smith, M. P. and Estrade, G., 2018. Unconventional ion-adsorption type REE deposits, what lies beneath: a case study from northwest Madagascar [oral presentation]. RFG 2018: Resources for Future Generations, Vancouver, Canada 16-21 June 2018.

Was given to an audience of academics (professional practitioners), postgraduate students and industry representatives.
Year(s) Of Engagement Activity 2018
URL http://www.rfg2018.org/
 
Description Presentation by PhD student at ERES 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation at ERES 2017 conference. Abstract: ERES2017: 2nd European Rare Earth Resources Conference|Santorini|28-31/05/2017 1
A NATURAL LABORATORY FOR ION ADSORPTION-TYPE REE DEPOSITS: THE AMBOHIMIRAHAVAVY ALKALINE COMPLEX IN NORTHWEST MADAGASCAR
Eva MARQUIS1, Martin SMITH1, Guillaume ESTRADE2, Kathryn GOODENOUGH3
1 School of Environment and Technology, University of Brighton, Lewes Road, Brighton, UK
2 Géosciences Environnement Toulouse, Université Toulouse III Paul Sabatier, Toulouse, F
3 British Geological Survey, the Lyell Centre, Research Avenue South, Edinburgh, UK
e.marquis@brighton.ac.uk
Ion Adsorption-Type Deposits
Ion Adsorption-Type Deposits (IADs) are the principal source of HREE and yttrium to the global market1. These supergene deposits contain >50% ion exchangeable REE (+Y) adsorbed to the surface of clay minerals, typically kaolinite and halloysite. Although these deposits are typically low-grade with respect to REE contents, it is the ease of extraction, plus low uranium and thorium contents that makes IADs economically desirable1. Known IADs are located in southern China, Brazil, Malawi, Madagascar and southeast Asia, in tropical to temperate climates. Climate plays an important role in the formation of IADs, providing the temperature and precipitation required for the intense lateritic weathering. At present, large-scale economic extraction of IADs occurs exclusively in southern China1. Heavy REE enriched IADs in China are typically restricted to areas underlain by muscovite granites, which have undergone a degree of deuteric alteration that formed easily degradable REE-minerals (e.g. fluorcarbonates)1. The presence of HREE-enriched protoliths containing easily degradable REE-bearing minerals seems to be the primary control on the formation of HREE-enriched IADs, but there has been limited investigation into how these minerals form and evolve. This talk describes ongoing research on the protoliths of an IAD in Madagascar, and considers the bedrock controls on mineralisation.
Ambohimirahavavy Alkaline Complex
Peralkaline igneous rocks are typically enriched in the HREE, but processing of these 'hard-rock' deposits is challenging. The Cenozoic-age Ambohimirahavavy alkaline igneous complex in Madagascar has undergone intense tropical weathering leading to the formation of easily processed IAD-type ores within thick weathered profiles. The Ambohimirahavavy Complex is an eroded caldera, comprising silica-over- and -under-saturated syenitic and granitic intrusions3, and alkaline volcanic rocks (Fig. A). The most REE-enriched protoliths are peralkaline granite sheets with grades up to
ERES2017: 2nd European Rare Earth Resources Conference|Santorini|28-31/05/2017 2
SedimentsComplexesAmbohimirahavavyComplexComplexManongarivoComplexBezavonaComplexAndranomatavyMesozoic SedimentsCenozoicAlkali VolcanicSedimentsComplexes
2.24% TREO2. Ion adsorption-type ores are distributed unevenly across the entire complex and carry an average grade of 835 ppm TREO2.
Petrographic analysis of various syenites and peralkaline granite dykes from across the complex has identified multiple forms of REE-mineralisation including late-magmatic (pyrochlore, zircon, eudialyte) and hydrothermal phases (allanite, REE-fluorcarbonates). High temperature alteration of REE-minerals potentially results in the release of REE into forms more amenable to decomposition during chemical weathering (e.g. REE-fluorcarbonates). These minerals are not only found in magmatic rocks but also in pegmatitic veins intruding extensive damage zones within country rocks surrounding the complex. Initial observations indicate that the magmatic and hydrothermal development may be critical for the development of an economic supergene deposit.
Year(s) Of Engagement Activity 2017
 
Description Presentation to All-Party Parliamentary Group on Mining and Quarrying 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Presentation to All-Party Parliamentary Group on Mining and Quarrying on A new type of REE deposit: Ion Adsorption Deposits. Presentation mainly to policy makers, with questions and discussion afterwards.
Year(s) Of Engagement Activity 2018
 
Description Presentation to Cafe Scientificque, Brighton, titled: 'What's so critical about metals? - Resources for the renewable revolution', by M. Smith 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Presentation to the General public at the Café Scientifique, Brighton. 67 attendees from the general public and university.
Year(s) Of Engagement Activity 2019
URL https://www.meetup.com/Brighton-Cafe-Scientifique/events/261546572/
 
Description Presentation to SEG chapter, Portsmouth 2/2/2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Undergraduate students
Results and Impact Presentation on previous research, research review, and preliminary results from SOS:Rare
Year(s) Of Engagement Activity 2016
 
Description Presentation to SOS:Minerals meeting, Leicester - The Ampasindava peninsula, Madagascar: 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Study participants or study members
Results and Impact Progress presentation to the thematic programme progress meeting.
Year(s) Of Engagement Activity 2016
 
Description Presentation to the European Micro-analysis society (EMAS) titled: STRUCTURAL STATE OF REE IN ION ADSORPTION DEPOSITS: A XANES/EXAFS STUDY OF LATERITES FROM MADAGASCAR AND CHINA. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation to an audience of professional practitioners, postgraduate students and industry representatives titled: STRUCTURAL STATE OF REE IN ION ADSORPTION DEPOSITS: A XANES/EXAFS STUDY OF LATERITES FROM MADAGASCAR AND CHINA. Lead to discussion and requests for further information.
Year(s) Of Engagement Activity 2018
URL https://www.microbeamanalysis.eu/events/event/51-emas-2018-microbeam-analysis-in-the-earth-sciences
 
Description Presentation to the Mineral Deposits Studies Group Annual Meeting 2018-19 titled: Adsorption experiments of REE onto kaolinite at 0.025 and 0.5 M NaCl. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation to the Mineral Deposits Studies Group Annual Meeting 2018-19 titled: Adsorption experiments of REE onto kaolinite at 0.025 and 0.5 M NaCl, by
C. Villanova-de-Benavent and M.P. Smith to an audience of professional practitioners, post graduate students and industry representatives.
Year(s) Of Engagement Activity 2019
URL https://mdsg2019.co.uk/
 
Description Presentation to the Mineral Deposits Studies Group Annual Meeting 2018-19 titled: Micro- to Macroscale controls on REE distribution in the Ambohimirahavavy ion adsorption deposit, Madagascar. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation to the Mineral Deposits Studies Group Annual Meeting 2018-19 titled: Micro- to Macroscale controls on REE distribution in the Ambohimirahavavy ion adsorption deposit, Madagascar. An audience of professional practitioners, post graduate students and industry representatives.
Year(s) Of Engagement Activity 2019
URL http://mdsg2019.co.uk/
 
Description Public lecture to Worthing Geological Society - REE concentration and fractionation in natural systems: Formation of the world's largest REE resources. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Evening presentation to amateur geological society, primarily members of the general public. Approximately 20-30 attendees, with questions and feedback about new awareness of the issues around critical metals.
Year(s) Of Engagement Activity 2016
 
Description The Jekyll and Hyde of rare earths 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact An article in Materials World - the magazine of the Institute of Materials, Minerals and Mining - on ion adsorption deposits of the Rare Earth elements. Distributed to all members and some institutional libraries.
Year(s) Of Engagement Activity 2018
URL https://www.iom3.org/materials-world-magazine/feature/2018/jul/01/good-and-bad-rare-earths