Martin Peter Smith

University of Brighton · School of Environment and Technology

Alkaline-peralkaline igneous systems are promising sources of Rare Earth Elements (REE). Preservation bias has resulted in a gap in the geological record for alkaline-peralkaline magmatic systems, with the hypabyssal plumbing system linking magma chambers to extrusive volcanic rocks poorly represented. Large plutonic varieties of these systems are...

Carbonatite intrusions host the world’s most important light rare earth element (LREE) deposits, and their formation generally requires extraordinary fertile sources, magmatic evolution, and hydrothermal events. However, carbonatitic magma evolution, particularly the role of fractional crystallization and contamination from silicate rocks in REE en...

The increasing global demand for the rare earth elements (REE), that are critical for green energy production, justifies the necessity of understanding REE ore formation processes [1]. The main type of REE mineralization is mostly found in association with carbonatites and alkaline rocks [1,2]. In addition, in some cases the REE can also reach econ...

Weathering crusts after granites are the most important source of heavy rare-earth elements (HREE) worldwide. Although HREE in these deposits is known to be inherited from parental rocks, the origin of HREE enrichment and the reasons why it is rare outside of China remains unclear. Here, we report the occurrence of variably organized nanoparticles...

Rare earth elements (REEs + Y) play an important role in modern industry. Heavy REEs (HREEs) are particularly critical because of their relative scarcity in nature. Global HREE resources are predominantly present in granitoid weathering crusts in southern China. Although it is well known that REEs are generally enriched in alkaline rocks, in contra...

The physico-chemical changes occurring during the high-temperature phase transformation of monazite in the presence of Na2CO3 at 1000 °C for 2 h duration at monazite: Na2CO3 ratios between 1.0 and 5.0, were investigated. The formation of sodium lanthanide phosphates was prevalent above a monazite:alkali ratio of 2, however, below this ratio, the de...

In this study, a geotechnical centrifuge has been used to study the unsaturated hydraulic properties of rock samples from the chalk aquifer, south east England. This method allows rapid measurement of hydraulic properties in a controlled environment, in contrast to previous studies on the chalk unsaturated zone which required either an extended per...

The genesis of the Bayan Obo giant rare earth element (REE) deposit has been debated for several decades. Here, we report the isotopic effects of dynamic recrystallization in the H8 carbonatite, which is the principal ore carrier in the deposit. We studied fresh drill core to a depth of 1.78 km and documented the elemental and C-O-Sr isotope evolut...

The Nalunaq deposit, Greenland, is a hypozonal, shear zone-hosted, Au deposit. The shear zone has previously been interpreted to have undergone 4 stages of deformation, accompanied by fluid flow,and vein formation. Coupled with previous trapping T estimates, fluid inclusion data are consistent with trapping of fluids with salinities between 28-45 w...

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The Chalk aquifer is one of the main sources of water in South East England. The unsaturated zone in the aquifer plays an important role controlling the time and magnitude of recharge and is major pathway for contaminant transport to the water table. A range of previous work has addressed flow processes in the Chalk unsaturated zone, but physical u...

Aynak is the largest known copper deposit in Afghanistan, with indicated resources of 240 Mt grading 2.3% Cu placing it in the ‘giant’ category. Host rocks are Neoproterozoic metasediments comprising dolomitic marble, carbonaceous quartz schist and quartz-biotite-dolomite schist containing garnet, scapolite and apatite. Chalcopyrite and bornite dom...

Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits in which the REE are inferred to be weakly adsorbed onto clay minerals. Similar deposits elsewhere might provide alternative supply for these high-tech metals, but the adsorption mechanisms remain unclear and the adsorbed...

Peralkaline granites and pegmatites are a prime repository of REE and HFSE, critical raw materials. Although it is accepted that magmatic processes are fundamental in concentrating these metals, the role of hydrothermal fluids in concentrating and fractionating these elements remains unclear. This paper investigates the global reproducibility of th...

Sulfur-bearing monazite-(Ce) occurs in silicified carbonatite at Eureka, Namibia, forming rims up to ~0.5 mm thick on earlier-formed monazite-(Ce) megacrysts. We present X-ray photoelectron spectroscopy (XPS) data demonstrating that sulfur is predominantly accommodated in monazite-(Ce) as sulfate, via a clino-anhydrite-type coupled substitution mec...

The Huanglongpu carbonatites are located in the north-western part of the Qinling orogenic belt in central China. Calcite carbonatite dykes at the Dashigou open pit are unusual due to their enrichment in heavy rare earth elements ( HREE ) relative to light rare earth elements ( LREE ), leading to a flat REE pattern, and in that the majority of dyke...

Carbonatites are abundant in the rare earth elements (REE), and they host the most important REE resources in the world. However, the mechanisms that concentrate these elements during carbonatitic magmatic processes are still poorly constrained. Here, we report the occurrence of apatite-hosted melt inclusions from the Ulgii Khiid carbonatites, Mong...

Accelerated low water corrosion is a form of marine steel corrosion caused by bacterial activity. It has a global spread and is potentially responsible for billions of pounds of damage. We have determined in detail both the chemistry of corrosion products and the associated microbiology at a UK site. The corrosion products form a layered structure...

Ion adsorption deposits, in which the rare earth elements (REE) occur adsorbed onto clay mineral surfaces, currently provide the world’s dominant supply of heavy REE (Gd-Lu). Concentration of REE within ion adsorption deposits has been proposed to be a dominantly supergene process, where easily degradable REE-minerals (e.g. REE-fluorcarbonates) bre...

Study of both peralkaline NYF and peraluminous LCT rare-metal pegmatites highlights the importance of key processes that significantly impact critical-metal prospectivity. The two pegmatite types discussed here form from very different sources, with the NYF pegmatites derived by evolution of a mantle-derived magma, and the LCT pegmatites formed by...

The silico‑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. The textures of REE minerals indicate crystallisation of monazite-(Ce), bastnäsite-(Ce), parisite-(Ce) and aeschynite-(Ce) as...

The Lugiin Gol nepheline syenite intrusion, Mongolia, hosts a range of carbonatite dikes mineralized in rare-earth elements (REE). Both carbonatites and nepheline syenite-fluorite-calcite veinlets are host to a previously unreported macroscale texture involving pseudo-graphic intergrowths of fluorite and calcite. The inclusions within calcite occur...

The unique, giant, rare earth element (REE) deposit at Bayan Obo, northern China, is the world's largest REE deposit. It is geologically complex, and its genesis is still debated. Here, we report in situ Th-Pb dating and Nd isotope ratios for monazite and Sr isotope ratios for dolomite and apatite from fresh drill cores. The measured monazite ages...

Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain hi...

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Scapolites from barren regional NaCl metasomatic assemblages (RM), iron oxide-copper-gold deposits (IOCG), scapolite altered metabasic rocks (IOCG-M), and from IOCG-proximal alteration/Na-Skarns (IOCG-PS) from Norrbotten County in Northern Sweden have been analysed for halogen content and Cl stable isotope composition. The aim of the study was to c...

Carbonatites, usually occurring within intra-continental rift-related settings, have strong light rare earth element (LREE) enrichment; they rarely contain economic heavy REE (HREE). Here, we report the identification of Late Triassic HREE-Mo-rich carbonatites in the northernmost Qinling orogen. The rocks contain abundant primary HREE minerals and...

Titanite occurs as a widespread accessory phase in mineralised zones and alteration associated with iron oxide-copper gold (IOCG) and iron oxide-apatite (IOA) deposits of Norrbotten County, Sweden, and is a major host of the REE in these deposits. In situ analyses of Sm[single bond]Nd isotope ratios in titanites previously analysed for U[single bon...

This study utilises geochemical provenancing of silcrete raw materials, in combination with chaîne opératoire analyses, to explore lithic procurement and behavioural patterns in the northern Kalahari Desert during the Middle Stone Age (MSA). New data from the sites of Rhino Cave, Corner Cave, and ≠Gi in northwest Botswana, combined with earlier res...

The rare earth elements are unusual when defining giant-sized ore deposits, as resources are often quoted as total rare earth oxide, but the importance of a deposit may be related to the grade for individual, or a limited group of, the elements. Taking the total REE resource, only one currently known deposit (Bayan Obo) would class as giant (>1.7×1...

Current European manufacturing relies heavily on imports from China for unprocessed rare earth elements (REEs) and rare earth oxides (REOs). It has been suggested that the EU holds viable reserves of REEs that, with adequate research, could satisfy 10% of EU demand, by the recycling of mine waste from bauxite production (red muds) alone[1]. Focus h...

The magnetite deposits of the Turgai belt (Kachar, Sarbai and Sokolov), in the Valerianovskoe zone of the southern Urals, Kazakhstan, contain a combined resource of over 3Gt of iron oxide ore. The deposits are hosted by carbonate sediments and volcaniclastic rocks of the Carboniferous Valerianovka Supergroup, and are spatially related to the gabbro...

Current climate change models for the south east UK predict changing rainfall patterns, with increased incidence of extreme events. The Chalk aquifer in the UK and northern France is susceptible to groundwater induced flooding under such conditions. In this methodological study we apply a frequency domain analysis approach to the Chalk aquifer to d...

Current European manufacturing relies heavily on imports from the USA & China for unprocessed rare earth elements (REEs) and rare earth oxides (REOs). It has been suggested that the EU holds viable reserves of REEs that, with adequate research, could satisfy 10% of EU industrial demand, by the recycling of mine waste from bauxite production (red mu...

Sideritic ironstones have extensive occurrence on a basin-wide scale in the Weald Basin, southeast England. They occur as nodules, tabular ironstone bands and sometimes as spherulites. The most common sideritic horizons are very important stratigraphic units at base of the Wadhurst Clay Formation (Berriasian-Valanginian) and represent important mar...

Ore deposits form by a variety of natural processes that concentrate elements into a small volume that can be economically mined. Their type, character and abundance reflect the environment in which they formed and thus they preserve key evidence for the evolution of magmatic and tectonic processes, the state of the atmosphere and hydrosphere, and...

Palaeo-environmental reconstructions of the fluvial Wealden strata in southeast England have been based mainly on field, fossil and mineralogical data. We present new insights into the palaeo-depositional environments of these Lower Cretaceous sediments based on the analyses of petrographic, geochemical and siderite data. Field and mineralogical da...

Heterogeneity occurs at different levels within the Lower Cretaceous Weald Basin in Sussex, southeast England. Based on field studies, petrographic and petro-physical data we present key variations in space and time within the non-marine Wealden sandstones from Sussex. Within the Ashdown Formation grain size generally increases with time while it i...

Carbonatites as a rock type typically show some of the highest rare earth element (REE) enrichments seen in bulk earth materials, and either directly form economic REE deposits (e.g. Mountain Pass), are the protolith of metamorphosed and remobilised deposits (e.g. Bayan Obo), or are part of the bedrock sequence in weathered and lateritic deposits (...

Ashdown sandstones (late Berriasian to early Valanginian) and Wadhurst Clay (early to mid Valanginian) show excellent exposures along the coast in the Weald, southeast England. Together with other Wealden sediments they provide important type sections for the Lower Cretaceous successions of northwest Europe. Their significance in constraining Early...

Lithic artifacts from the African Middle Stone Age (MSA) offer an avenue to explore a range of human behaviors, including mobility, raw material acquisition, trade and exchange. However, to date, in southern Africa it has not been possible to provenance the locations from which commonly used stone materials were acquired prior to transport to archa...

The Chalk aquifer of South East England is a major groundwater resource and regionally supplies up to 70% of all water abstracted for potable purposes. The two main pressures on groundwater resources are considered to be climate change and population growth. As the demand for water increases, so does the volume of wastewater that has to be treated...

Iron oxide–copper–gold (IOCG) deposits and Fe oxide-apatite deposits from Norrbotten, Sweden, formed in similar settings, and in some cases IOCG mineralisation overprinted Fe oxide-apatite mineralisation. Fluid inclusions in quartz veins cutting Fe oxide-apatite deposits range in salinity from 33 to 37 wt.% NaCl eq., and those in IOCG-type deposits...

Uncontrolled landfill disposal can cause the release of significant contamination. In Southern England and in other parts of the UK, historical landfills are located along many coastal and estuarine marshes and mudflats. At these sites waste, often significantly contaminated with heavy metals and other contaminants, was dumped with little engineeri...

This paper describes data obtained from tensiometers installed through 60 m of the unsaturated zone of a site situated on the Chalk aquifer of southern England. The data are interpreted together with consideration of previous work on unsaturated zone processes. The data show that, at the North Heath Barn site near Patcham (West Sussex, UK), matric...

As a source of strategic commodities for high technologies, the deposits of rare earth elements (REEs) in China are a world-class phenomenon. The combination of the world's largest accumulation of REEs in the Bayan Obo deposit and the low cost of mining the extremely valuable heavy REEs from residual deposits makes China almost a monopoly producer....

The CLIMAWAT project is an EU-Regional Development Fund Interreg IV funded research programme to study the impacts of climate change on groundwater resources and groundwater quality from the Chalk aquifer of SE England. The use of partially treated wastewater for artificial recharge will also be extensively studied in both the field and laboratory....

Northern Norrbotten, Sweden is a key part of Baltic Shield and provides a record of magmatic, tectonic and related, superimposed, Fe oxide-apatite and iron oxide-copper-gold (IOCG) mineralization, during the Svecokarelian orogeny. Titanite and allanite from a range of mineral deposits in the area have been analysed for U-Pb isotope systematics and...

We have analysed the halogen concentrations and chlorine stable isotope composition of fluid inclusion leachates from three spatially associated Fe-oxide ± Cu ± Au mineralising systems in Norrbotten, Sweden. Fluid inclusions in late-stage veins in Fe-oxide–apatite deposits contain saline brines and have a wide range of Br/Cl molar ratios, from 0.2...

The purpose of this study was to consider the use of a hydroxyapatite (HA) coated porous carbon matrix as a synthetic dental laminate substitute in osteo-odonto-keratoprosthetic (OOKP) design. 3 types of carbon meshes were coated with HA by sonoelectrochemical deposition. The materials were characterised by scanning electron microscopy (SEM) and HA...

In situ U–Pb dating of a variety of mineral phases is an important goal in petrology. This study reports data chiefly from titanite, but also from rutile and apatite, obtained using the laser ablation (LA)-ICP-MS methodology on polished thick sections in order to retain as much petrologic information as possible, and allowing trace element analyses...

The Rakkurijarvi prospect consists of a group of mineralized magnetite and lithic breccias within the ca. 2.0-5- to 1.90-Ga Proterozoic supracrustal sequence of the Kiruna district, northern Sweden. Potentially economic grades of Cu and Au, largely in the form of chalcopyrite and other sulfide assemblages, are hosted in brecciated magnetite and met...

Fenite aureoles around carbonatite dykes, and alteration associated with Fe-REE-Nb ore bodies at Bayan Obo, Inner Mongolia, China, show alkali silicate assemblages containing aegirine-augite, (magnesio-)riebeckite, (magnesio-)arfvedsonite, and phlogopite, accompanied by varying amounts of apatite, albite and quartz. In both fenites and orebodies si...

U–Pb geochronology using laser ablation ICP–MS is a fairly recently introduced technique and thus far its development has centred on zircon dating. Using titanite as an example, the application of laser ablation ICP–MS to U–Pb dating of common Pb-bearing accessory phases is presented. A simple analytical set-up, comprising a 213 nm Nd:YAG laser cou...

The northern Norrbotten area in northern Sweden, is an important mining district and hosts several deposits of Fe-oxide Cu-Au-type. One of the best examples of spatially, and possibly genetically, related apatite–iron and copper–gold deposits in the region is at Tjårrojåkka, 50km WSW of Kiruna. The deposits are hosted by strongly sheared and metamo...

The nature and mode of origin of quartz-cored tourmalines (QCT) are studied from hydrothermal quartz veins within massive quartz-tourmaline (MQT) rocks at Roche, SW England. The QCT are annular, have blue maximum absorption colour and occur together with tourmalines with brown cores rimmed by blue tourmaline. Where the quartz core is not continuous...

Established techniques for the laser ablation ICP-MS U-Pb analysis of zircon have been developed for application to common Pb bearing phases, including titanite and allanite. A novel common Pb correction procedure has been developed for deriving mineral ages, and has been tested using well characterised samples. This technique has been applied to s...

Norrbotten County, Sweden, is well known for the iron oxide-apatite deposits of the Kiruna and Malmberget areas. These are spatially associated with iron oxide Cu (± Au) deposits and a genetic link between the two has been suggested as a part of the IOCG spectrum of deposits. Here, we report the results of a fluid inclusion microthermometry and bul...

Garnets from skarns in the Beinn an Dubhaich granite aureole, Isle of Skye, Scotland, have a large range of concentrations of uranium (0.2-358 ppm) and the rare earth elements (REE) (23-4724 ppm). Variations in these concentrations correlate with major element zonation within the garnets, and with changes in the shape of REE patterns. Typical patte...

Chemical composition and crystal structure of natural non-metamict Fe-rich chevkinite-(Ce) from the aegirine-alkali granite, Mianning, Sichuan Province, China, were investigated. Microprobe analyses indicated that FeO (total iron) content in Ferich chevkinite(Ce) ranges from 10.97 % to 11.59 % (wt.) and Ce2O3 from 23 % to 25 %. There are deficient...

Allanite-(Ce) occurs as a metasomatic phase in diopside-hedenbergite-anorthite-hastingsite endoskarn from the Beinn an Dubhaich granite aureole, Skye. Fluid-inclusion studies indicate formation of pyroxene at temperatures in the range 600-700degreesC from Na-K-Fe-Ca beating brines (45-60 wt. % NaCl eq.) assuming pressures of 280-640 bars. Allanite...

Fluid inclusion salinities from quartz veins in the Otago Schist, New Zealand, range from 1.0 to 7.3 wt% NaCl eq. in the Torlesse terrane, and from 0.4 to 3.1 wt% NaCl eq. in the Caples terrane. Homogenization temperatures from these inclusions range from 124 to 350 °C, with modal values for individual samples ranging from 163 to 229 °C, but coexis...

Apatite occurs in the zeolite to greenschist facies metamorphic rocks of the Otago Schist, South Island, New Zealand, as both a groundmass constituent and as a hydrothermal phase hosted in metamorphic quartz veins. Groundmass apatite from low-grade rocks, ranging from the zeolite facies to the pumpellyite–actinolite zone, has chloride contents rang...

The aeschynite-group minerals occurring in an aegirine-fluorite-dolomite- aeschynite vein in the Bayan Obo Nb-REE-Fe deposit show complex compositional zoning in BSE images, Microprobe analyses revealed that the concentrations of REE2O3 are globally high in aeschynite-group minerals, ranging from 36.72 to 40.32 wt.%. Four species were identified in...

The Bayan Obo Fe-REE-Nb deposit, Inner Mongolia, China, is the world's largest REE resource and is also exploited as a major Fe oxide deposit. The deposit consists of replacement bodies hosted in dolomite marble and of magnetite, hematite, and REE minerals associated with apatite, aegirine, amphibole, fluorite, calcite, and barite. Fluid inclusions...

Chemical compositions of bastnaesite-synchysite polysomatic series minerals from the Maoniuping aegirine-alkali granite massif have been studied by electron microprobe. Syntaxial intergrowth of the polysomatic minerals is commonly observed. Bastnaesite with enriched LREE occurs replacing the polysomes. For the polysomes with the mixed-layer structu...

The composition of REE minerals from the Bayan Obo Fe-REE-Nb deposit, China, varies widely with paragenesis. The properties of fluid inclusions also vary with paragenesis, indicating changing fluid conditions during the deposits formation. In early disseminated monazite and in the main stage banded ores, the chondrite normalised La/Nd ratio varies...