Special Issue "Toward Mineral Systems for HFSE Rare Metals"

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Geochemistry and Geochronology".

Deadline for manuscript submissions: closed (30 November 2018)

Special Issue Editors

Guest Editor
Prof. Anne-Sylvie Andre-Mayer

GeoRessources Laboratory, Université de Lorraine-CNRS-CREGU, Nancy, France
Website | E-Mail
Interests: mineral system; Proterozoic; gold; uranium; rare metals
Guest Editor
Prof. Olivier Vanderhaeghe

Géosciences Environnement Toulouse, GET, Université de Toulouse, CNRS, IRD, UPS, CNES (Toulouse), France
Website | E-Mail
Interests: structural analysis; petrology; geochronology; tectonics; geodynamics; migmatites; orogeny; crustal growth and differentiation; mineral systems
Guest Editor
Dr. Kathryn Goodenough

British Geological Survey, Edinburgh EH9 3LA, United Kingdom
Website | E-Mail
Interests: critical metals; rare earth elements; magmatic-hydrothermal; alkaline rocks; pegmatites

Special Issue Information

Dear Colleagues,

This Special Issue, “Toward Mineral Systems for HFSE Rare Metals”, will welcome studies dealing with distribution and fractionation of rare metals within the crust at different temporal and spatial scales. The rare metals are predominantly either large-ion-lithophile elements (LILE) or high-field-strength elements (HFSE). This Special Issue proposes to focus on HFSE that are considered to behave as a coherent group during geological processes, in relation to their similar crystal-chemical properties.

From (nano)micro to continental scale, from single to polyphase processes during an orogenic cycle, from deep to subsurface processes, papers using rare metals and their deposits as traces of crustal growth and differentiation, or taking a mineral system approach to understanding rare metal deposits, will be welcomed.

Prof. Anne-Sylvie Andre-Mayer
Prof. Olivier Vanderhaeghe
Dr. Kathryn Goodenough
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • rare metals
  • HFSE
  • mineral system
  • deposits
  • magmatism
  • hydrothermal
  • crustal growth and differentiation

Published Papers (6 papers)

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Research

Open AccessArticle Chemical Evolution of Nb-Ta Oxides and Cassiterite in Phosphorus-Rich Albite-Spodumene Pegmatites in the Kangxiwa–Dahongliutan Pegmatite Field, Western Kunlun Orogen, China
Minerals 2019, 9(3), 166; https://doi.org/10.3390/min9030166
Received: 30 January 2019 / Revised: 18 February 2019 / Accepted: 2 March 2019 / Published: 8 March 2019
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Abstract
The Kangxiwa–Dahongliutan pegmatite field in the Western Kunlun Orogen, China contains numerous granitic pegmatites around a large granitic pluton (the Dahongliutan Granite with an age of ca. 220 to 217 Ma), mainly including barren garnet-, tourmaline-bearing pegmatites, Be-rich beryl-muscovite pegmatites, and Li-, P-rich [...] Read more.
The Kangxiwa–Dahongliutan pegmatite field in the Western Kunlun Orogen, China contains numerous granitic pegmatites around a large granitic pluton (the Dahongliutan Granite with an age of ca. 220 to 217 Ma), mainly including barren garnet-, tourmaline-bearing pegmatites, Be-rich beryl-muscovite pegmatites, and Li-, P-rich albite-spodumene pegmatites. The textures, major element contents, and trace element concentrations of columbite-group minerals (CGM) and cassiterite from three albite-spodumene pegmatites in the region were investigated using a combination of optical microscopy, SEM, EPMA and LA-ICP-MS. The CGM can be broadly classified into four types: (1) inclusions in cassiterite; (2) euhedral to subhedral crystals (commonly exhibiting oscillatory and/or sector zoning and coexisting with magmatic cassiterite); (3) anhedral aggregates; (4) tantalite-(Fe)-ferrowodginite (FeSnTa2O8) intergrowths. The compositional variations of CGM and cassiterite are investigated on the mineral scale, in individual pegmatites and within the pegmatite group. The evolution of the pegmatites is also discussed. The variation of Nb/Ta and Zr/Hf ratios of the cassiterite mimics the Nb-Ta and Zr-Hf fractionation trends in many LCT pegmatites, indicating that these two ratios of cassiterite may bear meanings regarding the pegmatite evolution. Full article
(This article belongs to the Special Issue Toward Mineral Systems for HFSE Rare Metals)
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Open AccessArticle A Workflow to Define, Map and Name a Carbonatite- or Alkaline Igneous-Associated REE-HFSE Mineral System: A Case Study from SW Germany
Minerals 2019, 9(2), 97; https://doi.org/10.3390/min9020097
Received: 4 December 2018 / Revised: 20 January 2019 / Accepted: 24 January 2019 / Published: 9 February 2019
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Abstract
Security of supply of “hi-tech” raw materials (including the rare earth elements (REE) and some high-field-strength elements (HFSEs)) is a concern for the European Union. Exploration and research projects mostly focus on deposit- to outcrop-scale description of carbonatite- and alkaline igneous-associated REE-HFSE mineralization. [...] Read more.
Security of supply of “hi-tech” raw materials (including the rare earth elements (REE) and some high-field-strength elements (HFSEs)) is a concern for the European Union. Exploration and research projects mostly focus on deposit- to outcrop-scale description of carbonatite- and alkaline igneous-associated REE-HFSE mineralization. The REE-HFSE mineral system concept and approach are at a nascent stage, so developed further here. However, before applying the mineral system approach to a chosen REE-HFSE metallogenic province its mineral system extent first needs defining and mapping. This shifts a mineral system project’s foundation from the mineral system concept to a province’s mineral system extent. The mapped extent is required to investigate systematically the pathways and potential trap locations along which the REE-HFSE mass may be distributed. A workflow is presented to standardize the 4-D definition of a REE-HFSE mineral system at province-scale: (a) Identify and hierarchically organize a mineral system’s genetically related sub-divisions and deposits, (b) map its known and possible maximum extents, (c) name it, (d) discern its size (known mineral endowment), and (e) assess the favorability of the critical components to prioritize further investigations. The workflow is designed to generate process-based perspective and improve predictive targeting effectiveness along under-evaluated plays of any mineral system, for the future risking, comparing and ranking of REE-HFSE provinces and plays. Full article
(This article belongs to the Special Issue Toward Mineral Systems for HFSE Rare Metals)
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Open AccessArticle 3D Modeling of the Epembe (Namibia) Nb-Ta-P-(LREE) Carbonatite Deposit: New Insights into Geometry Related to Rare Metal Enrichment
Minerals 2018, 8(12), 600; https://doi.org/10.3390/min8120600
Received: 7 November 2018 / Revised: 8 December 2018 / Accepted: 17 December 2018 / Published: 19 December 2018
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Abstract
Geological 3D modeling delivers essential information on the distribution of enrichment zones and structures in (complex) mineral deposits and fosters a better guidance to subsequent exploration stages. The Paleoproterozoic Epembe carbonatite complex showcases the close relation between enrichment of specific elements (Nb, Ta, [...] Read more.
Geological 3D modeling delivers essential information on the distribution of enrichment zones and structures in (complex) mineral deposits and fosters a better guidance to subsequent exploration stages. The Paleoproterozoic Epembe carbonatite complex showcases the close relation between enrichment of specific elements (Nb, Ta, P, Total Rare Earth Element (TREE) + Y) and shear zones by structural modeling combined with geochemical interpolation. Three-dimensional fault surfaces based on structural field observations, geological maps, cross-sections, and drillhole data are visualized. The model shows a complex, dextral transpressive fault system. Three-dimensional interpolation of geochemical data demonstrates enrichment of Nb, Ta, P, and TREE + Y in small, isolated, lens-shaped, high-grade zones in close spatial distance to faults. Based on various indicators (e.g., oscillating variograms, monazite rims around the apatite) and field evidence, we see evidence for enrichment during hydrothermal (re-)mobilization rather than due to magmatic differentiation related to the formation of the alkaline system. This is further supported by geostatistical analysis of the three-dimensional distribution of Nb, Ta, P, and Light Rare Earth Elements (LREE) with respect to discrete shear zones. Full article
(This article belongs to the Special Issue Toward Mineral Systems for HFSE Rare Metals)
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Open AccessArticle Geology and U-Th-Pb Dating of the Gakara REE Deposit, Burundi
Minerals 2018, 8(9), 394; https://doi.org/10.3390/min8090394
Received: 27 June 2018 / Revised: 4 September 2018 / Accepted: 5 September 2018 / Published: 7 September 2018
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Abstract
The Gakara Rare Earth Elements (REE) deposit is one of the world’s highest grade REE deposits, likely linked to a carbonatitic magmatic-hydrothermal activity. It is located near Lake Tanganyika in Burundi, along the western branch of the East African Rift. Field observations suggest [...] Read more.
The Gakara Rare Earth Elements (REE) deposit is one of the world’s highest grade REE deposits, likely linked to a carbonatitic magmatic-hydrothermal activity. It is located near Lake Tanganyika in Burundi, along the western branch of the East African Rift. Field observations suggest that the mineralized veins formed in the upper crust. Previous structures inherited from the Kibaran orogeny may have been reused during the mineralizing event. The paragenetic sequence and the geochronological data show that the Gakara mineralization occurred in successive stages in a continuous hydrothermal history. The primary mineralization in bastnaesite was followed by an alteration stage into monazite. The U-Th-Pb ages obtained on bastnaesite (602 ± 7 Ma) and on monazite (589 ± 8 Ma) belong to the Pan-African cycle. The emplacement of the Gakara REE mineralization most likely took place during a pre-collisional event in the Pan-African belt, probably in an extensional context. Full article
(This article belongs to the Special Issue Toward Mineral Systems for HFSE Rare Metals)
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Open AccessArticle Geochemical Characterization, Geochronology, and Geodynamic Implications of Grenville Rare Earths Bearing Syenites, Haut-Saint-Maurice, QC, Canada
Minerals 2018, 8(8), 336; https://doi.org/10.3390/min8080336
Received: 6 June 2018 / Revised: 14 July 2018 / Accepted: 26 July 2018 / Published: 5 August 2018
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Abstract
The syenites in the western part of the Grenville Province in Quebec have been known since the 1990s, but few studies have been carried out on them. Over the last three years, a mapping project carried out by the Ministère de l’Énergie et [...] Read more.
The syenites in the western part of the Grenville Province in Quebec have been known since the 1990s, but few studies have been carried out on them. Over the last three years, a mapping project carried out by the Ministère de l’Énergie et des Ressources naturelles has revealed the presence of several rare earth element (REE)–bearing syenitic intrusions in this area. In this paper, we present a geodynamic model for their formation based on geochemical, thermobarometric, and geochronological data. The intrusions were emplaced between 1038 +15/−13 Ma and 1009 ± 3 Ma. The syenites can be divided into two groups: (1) an older, REE-bearing group associated with a volcanic arc and (2) a younger group with lower REE contents associated with an anorogenic event. Formation temperatures were between 898 and 1005 °C, and pressures were between 2 and 10 kbar. This model involving two intrusive periods is in conflict with the model of a large, hot, long-duration collisional orogen proposed by Rivers et al. (2009) but is consistent with more recent studies. Full article
(This article belongs to the Special Issue Toward Mineral Systems for HFSE Rare Metals)
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Open AccessArticle Evidence for Nb-Ta Occurrences in the Syn-Tectonic Pan-African Mayo Salah Leucogranite (Northern Cameroon): Constraints from Nb-Ta Oxide Mineralogy, Geochemistry and U-Pb LA-ICP-MS Geochronology on Columbite and Monazite
Minerals 2018, 8(5), 188; https://doi.org/10.3390/min8050188
Received: 6 April 2018 / Revised: 23 April 2018 / Accepted: 25 April 2018 / Published: 30 April 2018
Cited by 1 | PDF Full-text (23039 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The Mayo Salah pluton, which is located in the North-Cameroon domain of Central African Bold Belt (CAFB), is emplaced as a laccolith in volcano-sedimentary schists of Poli series, and displays features of Rare-metal Granite (RMG). It is made of two main rock groups: [...] Read more.
The Mayo Salah pluton, which is located in the North-Cameroon domain of Central African Bold Belt (CAFB), is emplaced as a laccolith in volcano-sedimentary schists of Poli series, and displays features of Rare-metal Granite (RMG). It is made of two main rock groups: (1) the metaluminous barren muscovite granite (MsG) and (2) the Nb-Ta bearing peraluminous leucogranite (MsL) which expresses four subtypes. The evolved Rare-element MsL is subalkaline, slightly peraluminous (ASI = 1.01–1.21), and it displays flat REE chondrite-normalized patterns with a strong negative Eu anomaly (Eu/Eu* = 0.02–0.20). It belongs to the peraluminous low phosphorus Rare-element Granites and L-type igneous rocks, as shown by the relatively low Zr/Hf (4.8–14) and Nb/Ta (1.4–9.0) ratios and the positive slope of the Zr-Hf-Nb-Ta profile in spider diagrams. The rare-element-bearing mineral is represented by columbite-group minerals (CGM) and other Nb-Ta-oxides (Nb-rutile and pyrochlore supergroup minerals). The CGM is classified as Mn-columbite, with Ta# and Mn# ratios increasing from core to rim. Two stages of mineralization are identified; the earliest stage (CGM-I) consists in scattered tabular or prismatic euhedral grains that were related to magmatic fractionation. The latest stage (CGM-II) is expressed as a Ta-rich Mn hydrothermal CGM episode represented as rims and/overgrowths around and/or as veinlet crosscutting CGM-I or in cleavage planes of muscovite. The U-Pb dating of columbite and monazite of the Mayo Salah leucogranite indicates a late-Neoproterozoic magmatic-hydrothermal mineralization event from 603.2 ± 5.3 to 581.6 ± 7.2 Ma, as consistent with both late D2 to D3 events that were recorded in the CAFB in Cameroon, and the associated continental collision environment. The Nb-Ta mineralization of the Mayo Salah pluton provides evidence for the presence of RMG in Northern Cameroon of CAFB, and its temporal association with the youngest period of metallogenic epoch of Nb-Ta-ore formation in Africa associated to Pan-African times. Full article
(This article belongs to the Special Issue Toward Mineral Systems for HFSE Rare Metals)
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