SoS RARE at St Andrews


SoS RARE is a NERC and EPSRC (UK research council) funded consortium that included major Universities across the UK working on the value chain of rare earth metals from the deposit through to processing. It was part of a themed call for projects known as ‘SoS MinErals’ which targets elements for which there were Security of Supply (hence ‘SoS’) issues. SoS RARE was one of four consortia that were funded and this particular consortium focussed on the heavy rare earth elements and Nd. The St Andrews arm of the project (ref: NE/M010856/1) employed as a post-doctoral research fellow Dr Anouk Borst and a PhD student Nicky Horsburgh who was partly funded also by the University of St Andrews Seventh Century Scholarship scheme. A Iapetus-funded PhD studentship (Krzysztof Sokó­ł) was also allied to the SoS RARE project.


The St Andrews component of the consortium was to characterise better the key mineral resources for heavy rare earths and Nd, including not only ion adsorption clays, but also those occurring in peralkaline igneous systems. The target minerals for heavy rare earth extraction in peralkaline magmatic rocks are eudialyte and steenstrupine, but the processing and grade of the deposit is sometimes altered by late stage hydrothermal alteration of the minerals. The key objectives in SoS RARE were:

  1. To characterise the exact structural site of the REE in both eudialyte (the key peralkaline target ore mineral) and ion adsorption clay deposits in China which remain the world’s primary source, even though the exact nature of the deposit remains contentious.
  2. Understand further the nature of late-stage alteration in peralkaline ore minerals, including the drivers for the alteration, the nature of the subsequent products and the influence of subsequent yield,
  3. To explore whether the luminescence of rare earth-bearing minerals can be used as a tool for smart sorting, thereby reducing substantially the carbon footprint of mining.
  4. Dissemination of all the above results to industry, academia, the public and schools, the latter of which were via a series of outreach schemes.

Nicky, Anouk and Adrian visited the mineralogy group at the Universidade Sao Paulo in Brazil, taking part in a symposium and also visiting the Poços do Caldos intrusion in Minas Gerais Province, and the world’s largest Nb deposit at Araxà.

Anouk and Adrian established collaborations with the Universidade Agostinho Neto Luanda in Angola. The legacy of the Angolan Civil War (ending 2002) meant that access to these centres has been minimal. Adrian Finch, Anouk Borst and Pete Siegfried of GeoAfrica visited Luanda and Nejoio in Southern Angola in order to take the research we were carrying out in Northern Namibia to the Angolan audience. St Andrews then supervised four undergraduate students from Luanda in their dissertation studies. A summary of the fieldwork in Nejoio was published by Anouk.

The samples are available for collaborative research and their nature and locations can be determined using our web-portal (see below).

Scientific and Public Science Publications

Several publications in the academic open literature have resulted from SoS RARE and several more are in preparation. All are open access. Publications to date include (SoS RARE collaborators are highlighted in bold):

Sokó­ł K, Finch AA, Hutchison W, Cloutier J, Borst AM, Humphreys M (2022) Quantifying metasomatic HFSE-REE transport from alkaline magmas, Geology, 50, 305-310,

Borst AM, Smith MP, Finch AA, Estrade G, Villanova-de-Benavent C, Nason P, Marquis E, Horsburgh NJ, Goodenough KM, Xu C, Kynický J & Geraki K (2020) Adsorption of Rare Earth Elements in Regolith-Hosted Clay Deposits, Nature Communications, 11, 4386.

van de Ven M, Borst AM, Davies GR, Hunt EJ & Finch AA (2019) Hydrothermal Alteration of Eudialyte-Hosted Critical Metal Deposits: Fluid Source and Implications for Deposit Grade. Minerals, 9, 422;

Borst AM, Finch AA, Friis H, Horsburgh NJ, Gamaletsos PN, Goettlicher J, Steininger R & Geraki K (2019) Structural State of Rare Earth Elements in Eudialyte-Group Minerals. Mineralogical Magazine, 1-49. doi:10.1180/mgm.2019.50.

Borst AM (2019) New Frontiers of Critical Metal Exploration: Alkaline Igneous Rocks of Angola. The Applied Mineralogist, 4, no 4, 3-5. 

Finch AA, Hutchison W & Borst AM (2019) How Volcanoes Recycle the Earth’s Crust to Uncover Rare Metals that are Vital to Green Technology. The Conversation, article 125159.

Smith MP, Moore K, Kavecsánszki D, Finch AA, Kynicky J, Wall F (2016) From mantle to critical zone: a review of large and giant sized deposits of the rare earth elements. Geoscience Frontiers, 7, 315-334.

The project also partly supported a PhD thesis by Nicola Horsburgh which has been submitted and was vivaed in mid-March 2020. The other funder to the PhD project was the University of St Andrews Seventh Century Studentship Fund.

Horsburgh NJ (2020) “REE Induced Defects in Minerals: a Spectroscopic Study”.

Anouk also wrote the following paper from her PhD research whilst part of the SoS RARE team:

Borst AM, Waight TE, Finch AA, Storey M Roux PJL (2019) Dating agpaitic rocks: A multi-system (U/Pb, Sm/Nd, Rb/Sr and Ar-40/Ar-39) isotopic study of layered nepheline syenites from the Ilimaussaq complex, Greenland. Lithos, 324, 74–88. DOI:

Samples and Data

St Andrews used many of its sample collections as part of the project. The samples and their locations can be determined using our web-portal.

Data for each of the publications are presented alongside the presentations as supplementary data. Further datasets for each of the publications have been uploaded onto the St Andrews data repository Pure.

SoS RARE Outreach

In addition to the scientific programme, St Andrews has been involved in outreach activities associated with SoS RARE. St Andrews hosts the GeoBUS project, a free educational outreach for schools developed and run by the School of Earth & Environmental Sciences at the University of St Andrews since 2012. GeoBUS has developed and delivered materials regarding critical metals, rare earths and climate change as part of both the SoS RARE and HiTech AlkCarb projects, including fun resources such as Rare Earth ‘Top trumps’ and Critical Metals ‘Happy Families’.

Our sulfur isotope work (jointly with HiTech AlkCarb) was picked up by several national newspapers and summarised in a hot science topics journal called ‘The Conversation’.

Work on smart sorting from SoS RARE has led into an EPSRC-IAA impact acceleration grant “Smart Sorting for the Sustainable Production of Critical e-Tech Elements” which funded Dr Nicky Horsburgh and Dr Michael-John Treanor.

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