PhDs and postdocs: the next generation of minerals researchers

Project: SoS RARE

Student name: Delia Cangelosi

Location: University of Leeds

Supervisor(s): Dr David Banks (University of Leeds) and Prof Bruce Yardley (University of Leeds)

Project: SoS RARE

Student name: Eva Marquis

Location: University of Brighton

Supervisor(s): Dr Martin Smith (University of Brighton), Dr Kathryn Goodenough (British Geological Survey), Dr Norman Moles (University of Brighton)

Research summary: Ion adsorption clays are currently the world’s major source of heavy rare earth elements. The purpose of this investigation is to determine the preconditions necessary for the formation of ion adsorption clays that are strongly enriched in rare earth elements. Focusing on a series of alkaline complexes in North West Madagascar, this project will investigate the mobility of REE during the magmatic, hydrothermal and weathering evolution of the complexes. A multitude of techniques, including SEM, XRF, ICP-MS, LA-ICP-MS, and stable and radiogenic isotope analyses, will be used to understand the processes of involved in the concentration of rare earth elements in these unconventional deposits.

Project: TeASe

Student name: Joe Armstrong

Location: University of Aberdeen

Supervisor(s): Prof John Parnell (University of Aberdeen) and Dr Stephen Bowden (University of Aberdeen)

Research summary: A detailed geochemical study of organic-rich sedimentary and meta-sedimentary rocks. Specifically focussing on the mechanisms controlling the common enrichment of Tellurium, Selenium and other related trace elements in these lithologies.

Project: TeASe

Student name: Andrew Martin

Location: Cardiff University

Supervisor(s): Dr Hazel Prichard (Cardiff University) and Dr Iain McDonald (Cardiff University)

Research summary: Distribution and behaviour of Se and Te in Volcanogenic Massive Sulphide (VMS) systems Andrew Martin, Hazel Prichard and Iain McDonald Tellurium and selenium are identified as critical in low carbon energy technologies under the European Union's Strategic Energy Technology Plan (SET-Plan) (Moss et al., 2013). The use of Te and Se within photovoltaic cells (CdTe and CIGS) underpins their strategic importance within the EU and rest of the World. The criticality of these metals stems from the potential for significant growth in demand due to a transition to low carbon, solar dominated energy production (38 GW in 2010 to 630 GW in 2030- Moss et al., 2013), low crustal abundance 0.002 mg/kg Te and 0.05 mg/kg Se- Perkins, 2011) and their secondary (by-product) nature of production through the refining of copper (approximately 90%, Lu et al., 2015). Global Te production in 2010 was 0.50 Kt, projections by Moss et al. (2013) suggest that by 2030 the EU will consume over 50% of global Te production. It is clear that Te and Se will play a crucial role in the future transition to a low carbon economy; both currently lack recycling potential (Redlinger et al., 2015) and have little potential for substitution within photovoltaics (Lu et al., 2015), they are recovered solely from by-products through the electrolytic refining of copper which will decline in the future as Cu grades globally decrease favouring heap leach methods which are not amenable to Te-Se recovery (Moss et al., 2013). The future economic importance and significance of Te and Se in emerging technologies is paralleled by a poor understanding of the source, mobilisation and concentration of Te and Se within ore deposits. Te and Se have been of little interest in the recent past as production from copper refining has kept pace with global demand, it is evident this will not suffice in the future with demand set to significantly outstrip supply. To mitigate shortages and ensure security of supply research on all aspects of Te and Se is needed. Little is known about the partitioning of Se and especially Te within the magmatic environment (e.g. Liu and Brenan, 2015) with poorly constrained partition coefficients. Te mineral deportment is poorly characterised within the hydrothermal system, mineral affiliations and their impact on ore processing are not well defined. In addition the preferred Te ligand species or indeed the phase in which Te is transported (vapour vs. fluid) are poorly constrained (e.g. Grundler et al., 2013). Analytical capability, high detection limits and lack of acceptable high grade reference material has hindered accurate analysis (e.g. Schirmer et al., 2014). In combination these factors lead to a lack of comprehensive, accurate data which now needs to be implemented to mitigate future risks. To locate and understand the processes that concentrate Te and Se in Cu-rich VMS systems, known to concentrate these critical elements, the classic VMS deposits associated with the Troodos ophiolite have been chosen for study. Troodos is widely accepted to represent a suprasubduction oceanic spreading environment (Gass, 1980) and hosts numerous Cyprus type Cu rich stratabound VMS deposits averaging several millions of tonnes and Cu grades of ˜1-2% (see Adamides, 2011, 2010). This study will utilise recent high-resolution (ICP-MS) soil sample data collected from the whole of the southern part of Cyprus (Cohen et al., 2012) to locate Te and Se in rocks underlying the soil anomalies and so investigate the distribution of Te and Se on a lithology, deposit and mineralogical scale to ascertain the source and mechanism(s) for enrichment of Te and Se. This will allow the development of a genetic model for both Te and Se as a tool in Au exploration and a detailed understanding of mineralogical and geochemical controls of Te-Se distribution on a deposit scale allowing targeted extraction of Te and Se in the future. The aims are to understand the processes that concentrate Te and Se including variation in source composition within the hydrothermal system below the VMS deposits, the concentration of these elements as the VMS forms, the mobility within later off axis waning hydrothermal circulation and the secondary remobilisation of the elements during sea floor weathering. The objectives are to define an association of different types of VMS, e.g. more Cu, Pb, Zn or Au-rich with Te and Se enrichment and to ascertain whether Te and Se are associated with late off axis Au mineralisation. Is heterogeneity a function of preferential enrichment? Deposit genesis or source rock Te-Se composition? To investigate this hypothesis a geochemical map of southern Cyprus will be constructed in early 2016 (January - February) utilising the Cyprus geochemical soil data (kindly provided by the Cyprus Geological Survey) to identify potential targets exhibiting varied concentrations of Te and Se enrichment for further detailed analysis. Existing 'off axis' samples (after Prichard and Maliotis, 1998) will be used to assess the affiliation of Te with Au and if tellurides are associated with late stage, off axis hydrothermal fluids.

Project: TeASe

Student name: Callum Reekie

Location: University of Cambridge

Supervisor(s): Dr Helen Williams (University of Cambridge), Prof Marian Holness (University of Cambridge), Prof Colin Macpherson (Durham University), Dr Frances Jenner (The Open University) and Dr Geoff Bromiley (University of Edinburgh)

Research summary: Ph.D. research will aim to develop quantitative models for the stable isotope fractionation of Fe, Zn, Cu, and potentially Se, and chalcophile element behaviour during the differentiation of magmatic systems. Research will initially focus on calc-alkaline rocks of the Skaergaard intrusion, Greenland, and expand to consider major alkaline hydrothermal deposits such as Cripple Creek, Colorado. Experimental petrology will further be employed to examine stable isotope fractionation between sulphide and silicate liquids.

Project: MarineE-tech

Student name: Jane Collins

Location: University of Southampton

Supervisor(s): Dr Bramley Murton (National Oceanography Centre), Dr Mark Vard (University of Southampton), Prof Tim Henstock (National Oceanography Centre), Dr Tim Le Bas (National Oceanography Centre)

Research summary: Using an AUV, this PhD project will acquire acoustic backscatter data at different frequencies and incidence angles from one or more research cruises in the Atlantic.These will be combined with visual ROV ground-truthing to develop a novel and innovative thematic mapping algorithm that differentiates different seafloor types. The student will also use variation in the spectral response from AUV-derived chirp sub-bottom profiles to gather information about the thickness, lithology and roughness of sub-bottom sediment layers and interfaces. The geophysical approach will be augmented by laboratory tests (in the NOC pulse-tube) of collected crust samples to determine their response at different frequencies under controlled conditions.

Project: MarineE-tech

Student name: Sarah Howarth

Location: University of Southampton

Supervisor(s): Dr Bramley Murton (National Oceanography Centre), Dr Mark Vard (University of Southampton), Prof Tim Henstock (National Oceanography Centre), Dr Tim Le Bas (National Oceanography Centre)

Research summary: Ferromanganese crusts grow throughout the global ocean by direct precipitation from seawater and consist of thin layers (2 up to 25 cm thick) accumulated on hard substrate rocks over millions of years. Because of their extremely high specific surface area, and very slow growth rates, crusts sorb large quantities of elements from seawater, including those metals, such as REE, cobalt and tellurium, considered critical to high-technology and 'green' energy production. The environment of crust formation on seamounts is highly variable, affecting their composition and thickness at all spatial levels: ocean basin, regional, local, and within individual crusts. Geochemical studies of crusts from different water depths and locations reveal dependence in composition on a variety of factors. For example, we can distinguish between a metal group that is controlled by Mn- and a second group of metals that is closely related to the Fe+ content of the crusts. Both metal groups behave inversely and vary with water depth. In spite of the work already done on ferromanganese crusts, there is a clear need for investigation of the processes that control the origin, distribution, and resource potential of these deposits at local and sub-regional scales.The project focuses on the differences, and their causes, between NE and SW Atlantic crusts.