Rare Earth Element Fluorocarbonate Minerals from the Olympic Dam Cu-U-Au-Ag Deposit, South Australia

Schmandt, Danielle S.; Cook, Nigel J.; Ciobanu, Cristiana L.; Ehrig, Kathy; Wade, Benjamin P.; Gilbert, Sarah; Kamenetsky, Vadim S.

doi:10.3390/min7100202

Cited by 30 publications

(22 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In contrast to the lattice-scale intergrowths discussed here, end-member bastnäsite and synchysite have been documented from hematite-sericite-altered breccias hosting the Olympic Dam orebody [11]. On the other hand, the intimate, lattice-scale, relationships between BSG minerals and hematite [12] are not unique to this occurrence, a prospect distal to the deposit, but are also observed within the orebody, in which hematite hosts inclusions of BSG species [37].…”

Section: Implications and Outlookmentioning

confidence: 76%

“…The reader is referred to Supplementary Material Tables S2 and S3 in Schmandt et al [11] (www.mdpi.com/2075-163X/7/10/202/s1) for full details of elements analysed, peak/background positions, count times, reference standards, set-up parameters, elemental overlap corrections and minimum limits of detection. The instrument was operated at 15 kV and 20 na and with a spot size of 1 µm.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Short-Range Stacking Disorder in Mixed-Layer Compounds: A HAADF STEM Study of Bastnäsite-Parisite Intergrowths

et al. 2017

Self Cite

View full text Add to dashboard Cite

Atomic-scale high angle annular dark field scanning transmission electron microscopy (HAADF STEM) imaging and electron diffractions are used to address the complexity of lattice-scale intergrowths of REE-fluorocarbonates from an occurrence adjacent to the Olympic Dam deposit, South Australia. The aims are to define the species present within the intergrowths and also assess the value of the HAADF STEM technique in resolving stacking sequences within mixed-layer compounds. Results provide insights into the definition of species and crystal-structural modularity. Lattice-scale intergrowths account for the compositional range between bastnäsite and parasite, as measured by electron probe microanalysis (at the µm-scale throughout the entire area of the intergrowths). These comprise rhythmic intervals of parisite and bastnäsite, or stacking sequences with gradational changes in the slab stacking between B, BBS and BS types (B-bastnäsite, S-synchysite). An additional occurrence of an unnamed B 2 S phase [CaCe 3 (CO 3 ) 4 F 3 ], up to 11 unit cells in width, is identified among sequences of parisite and bastnäsite within the studied lamellar intergrowths. Both B 2 S and associated parisite show hexagonal lattices, interpreted as 2H polytypes with c = 28 and 38 Å, respectively. 2H parisite is a new, short hexagonal polytype that can be added to the 14 previously reported polytypes (both hexagonal and rhombohedral) for this mineral. The correlation between satellite reflections and the number of layers along the stacking direction (c*) can be written empirically as: N sat = [(m × 2) + (n × 4)] − 1 for all B m S n compounds with S = 0. The present study shows intergrowths characterised by short-range stacking disorder and coherent changes in stacking along perpendicular directions. Knowing that the same compositional range can be expressed as long-period stacking compounds in the group, the present intergrowths are interpreted as being related to disequilibrium crystallisation followed by replacement. HAADF STEM imaging is found to be efficient for depiction of stacking sequences and their changes in mixed-layer compounds, particularly those in which heavy atoms, such as rare-earth elements, are essential components.

show abstract

Section: Implications and Outlookmentioning

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Short-Range Stacking Disorder in Mixed-Layer Compounds: A HAADF STEM Study of Bastnäsite-Parisite Intergrowths

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…Some particularly refractory minerals may, in fact, preserve textural and compositional features that reveal deposit evolution better than many ore minerals. In our laboratory, these have ranged from garnets and other calc-silicate minerals in skarns [157,158], through fluorapatite [35,159,160] and REE-fluorocarbonates [43,161], to alkali and plagioclase feldspars [36,46]. A detailed investigation of hematite, which contributes as much as 80 wt % of the ore at Olympic Dam, has shown how this mineral can encode a wealth of valuable trace element information [162].…”

Section: The Significance Of Gangue Minerals-a Holistic Approach To Omentioning

confidence: 99%

Advances and Opportunities in Ore Mineralogy

et al. 2017

Self Cite

View full text Add to dashboard Cite

Abstract:The study of ore minerals is rapidly transforming due to an explosion of new microand nano-analytical technologies. These advanced microbeam techniques can expose the physical and chemical character of ore minerals at ever-better spatial resolution and analytical precision. The insights that can be obtained from ten of today's most important, or emerging, techniques and methodologies are reviewed: laser-ablation inductively-coupled plasma mass spectrometry; focussed ion beam-scanning electron microscopy; high-angle annular dark field scanning transmission electron microscopy; electron back-scatter diffraction; synchrotron X-ray fluorescence mapping; automated mineral analysis (Quantitative Evaluation of Mineralogy via Scanning Electron Microscopy and Mineral Liberation Analysis); nanoscale secondary ion mass spectrometry; atom probe tomography; radioisotope geochronology using ore minerals; and, non-traditional stable isotopes. Many of these technical advances cut across conceptual boundaries between mineralogy and geochemistry and require an in-depth knowledge of the material that is being analysed. These technological advances are accompanied by changing approaches to ore mineralogy: the increased focus on trace element distributions; the challenges offered by nanoscale characterisation; and the recognition of the critical petrogenetic information in gangue minerals, and, thus the need to for a holistic approach to the characterization of mineral assemblages. Using original examples, with an emphasis on iron oxide-copper-gold deposits, we show how increased analytical capabilities, particularly imaging and chemical mapping at the nanoscale, offer the potential to resolve outstanding questions in ore mineralogy. Broad regional or deposit-scale genetic models can be validated or refuted by careful analysis at the smallest scales of observation. As the volume of information at different scales of observation expands, the level of complexity that is revealed will increase, in turn generating additional research questions. Topics that are likely to be a focus of breakthrough research over the coming decades include, understanding atomic-scale distributions of metals and the role of nanoparticles, as well how minerals adapt, at the lattice-scale, to changing physicochemical conditions. Most importantly, the complementary use of advanced microbeam techniques allows for information of different types and levels of quantification on the same materials to be correlated.

show abstract

“…Within the deposit, REE are dominantly hosted in the REE-fluorocarbonate mineral bastnäsite [(REE)CO 3 F], in florencite [(REE)Al 3 (PO 4 ) 2 (OH) 6 ], and in subordinate amounts within synchysite [Ca(REE)(CO 3 ) 2 F], Sr-and Ca-dominant Al-phosphate-sulfates of the crandallite-and beudantite groups, as well as in xenotime and monazite [20,51]. Outside the deposit, a further REE-fluorocarbonate, parasite, is also observed [52,53], forming micron-to nanoscale intergrowths with bastnäsite and an unnamed species as part of a complex sericite + quartz + molybdenite assemblage replacing magmatic feldspar.…”

Section: Discussionmentioning

confidence: 99%

Numerical Modeling of REE Fractionation Patterns in Fluorapatite from the Olympic Dam Deposit (South Australia)

et al. 2018

Self Cite

View full text Add to dashboard Cite

Trace element signatures in apatite are used to study hydrothermal processes due to the ability of this mineral to chemically record and preserve the impact of individual hydrothermal events. Interpretation of rare earth element (REE)-signatures in hydrothermal apatite can be complex due to not only evolving f O 2 , f S 2 and fluid composition, but also to variety of different REE-complexes (Cl-, F-, P-, SO 4, CO 3 , oxide, OH − etc.) in hydrothermal fluid, and the significant differences in solubility and stability that these complexes exhibit. This contribution applies numerical modeling to evolving REE-signatures in apatite within the Olympic Dam iron-oxide-copper-gold deposit, South Australia with the aim of constraining fluid evolution. The REE-signatures of three unique types of apatite from hydrothermal assemblages that crystallized under partially constrained conditions have been numerically modeled, and the partitioning coefficients between apatite and fluid calculated in each case. Results of these calculations replicate the measured data well and show a transition from early light rare earth element (LREE)-to later middle rare earth element (MREE)-enriched apatite, which can be achieved by an evolution in the proportions of different REE-complexes. Modeling also efficiently explains the switch from REE-signatures with negative to positive Eu-anomalies. REE transport in hydrothermal fluids at Olympic Dam is attributed to REE-chloride complexes, thus explaining both the LREE-enriched character of the deposit and the relatively LREE-depleted nature of later generations of apatite. REE deposition may, however, have been induced by a weakening of REE-Cl activity and subsequent REE complexation with fluoride species. The conspicuous positive Eu-anomalies displayed by later apatite with are attributed to crystallization from high pH fluids characterized by the presence of Eu 3+ species.

show abstract

Rare Earth Element Fluorocarbonate Minerals from the Olympic Dam Cu-U-Au-Ag Deposit, South Australia

Cited by 30 publications

References 45 publications

Short-Range Stacking Disorder in Mixed-Layer Compounds: A HAADF STEM Study of Bastnäsite-Parisite Intergrowths

Short-Range Stacking Disorder in Mixed-Layer Compounds: A HAADF STEM Study of Bastnäsite-Parisite Intergrowths

Advances and Opportunities in Ore Mineralogy

Numerical Modeling of REE Fractionation Patterns in Fluorapatite from the Olympic Dam Deposit (South Australia)

Contact Info

Product

Resources

About