scholarly journals In Situ Chalcophile and Siderophile Element Behavior in Sulfides from Moroccan Middle Atlas Spinel Peridotite Xenoliths during Metasomatism and Weathering

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 276 ◽  
Author(s):  
Katrin J. Westner ◽  
Christoph Beier ◽  
Reiner Klemd ◽  
Inga Osbahr ◽  
Nadine Brooks
Keyword(s):  
Trace Elements ◽  
Solid Solutions ◽  
Inductively Coupled Plasma ◽  
Major And Trace Elements ◽  
Spinel Peridotite ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry ◽  
Middle Atlas ◽  
Mantle Processes

In situ chalcophile and siderophile major and trace elements were analyzed in sulfides from eight Moroccan Middle Atlas lherzolite xenoliths using electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The sulfides occur enclosed in primary silicates, interstitial in the peridotite matrix, and associated with glass-bearing melt pockets. Monosulfide solid solutions are enriched in these xenoliths relative to pentlandite and intermediate solid solutions. Regardless of the textural occurrence, sulfide platinum-group element (PGE) patterns are distinguished into residual ([Pd/Ir]N < 1 and [Pt/Pd]N > 1 or [Pt/Pd]N < 1), melt-like ([Pd/Ir]N > 1), and unfractionated patterns. The coexistence of both residual and melt-like PGE signatures on a cm scale in a single sample implies that sulfides may record initial depletion and subsequent re-enrichment more effectively than constituent silicates do. Chalcophile and siderophile trace elements other than the PGEs are fractionated between the precipitated sulfide phases, but do not vary systematically with the PGE signatures, suggesting that the PGEs are comparatively sensitive to melting and depletion. In addition, Fe-rich hydroxides generated by sulfide breakdown due to atmospheric weathering display PGE systematics almost identical to their precursor sulfides, implying that they may be reliable tracers of mantle processes even after extensive weathering.

Cationic Substitutions in Sphalerite from the Porgera Mine, Papua New Guinea

2021 ◽  
Author(s):  
Christopher H. Ingles ◽  
John A. Mavrogenes
Keyword(s):  
Solid Solution ◽  
Papua New Guinea ◽  
Solid Solutions ◽  
Inductively Coupled Plasma ◽  
New Guinea ◽  
Inductively Coupled ◽  
Cationic Substitution ◽  
Plasma Mass Spectrometry ◽  
Positive Correlations

ABSTRACT Laser ablation-inductively coupled plasma-mass spectrometry was used to traverse hydrothermal vein sphalerite from different ore-forming stages of the Porgera Au-Ag mine, Papua New Guinea. Elements were measured in situ over the growth of crystals to investigate the greatly varying concentrations of cations in sphalerite and their positions in the lattice. Traverse profiles for 16 elements were obtained and aligned to transmitted light images where possible. Each sample contained an array of elements, with many displaying orders of magnitude concentration differences. Results show the simultaneous incorporation of Cu and Sn in sphalerite, as well as Cu and Ag, In and Sn, As and Sb, Fe and Mn, and Cu and Ga. The relation [4Zn2+ ↔ 2Cu+ + Sn2+ + Sn4+] is proposed to explain the 1:1 Cu–Sn correlation. Further relations can be seen, including a Ga “ceiling” or Cu “floor”, where Ga incorporation becomes dependent on Cu concentrations. Furthermore, silver was also observed to correlate with Au, Mn, Ni, Pb, and Bi. Meta-stable solid solutions between pairs such as Cu, Ag; Fe, Mn; As, Sb; and In, Sn are also suggested. Each of these pairs are neighbors on the periodic table of elements, which suggests that simple solid solution can occur, and positive correlations for all four solid solutions were found in one sample alone. While the concept of charge-specific solid solutions in sphalerite has been discussed in the literature with reference to monovalent cations, the results presented herein also indicate solid solutions of higher oxidation states, containing many cations. Furthermore, while cations in charge-specific solid solutions have been proposed to compete for lattice sites in sphalerite, simultaneous in situ coupled concentrations at Porgera suggest otherwise. Cationic substitution equations displaying decimal ratios of each element in solid solution can then provide a novel method to distinguish between solid solution concentrations in different samples. For example, displaying 1:1 ratios of Cu–Ag and Sb–As: [2Zn2+ ↔ (Cu+0.5, Ag+0.5) + (As3+0.5, Sb3+0.5)], or for a 100:1 Fe–Mn ratio: [Zn2+ ↔ (Fe2+0.99, Mn2+0.01)].

scholarly journals Selected ions and major- and trace elements as contaminants in coal-waste dump water from the Lower- and Upper Silesian Coal Basins (Poland)

2020 ◽  
Author(s):  
Lucyna Lewińska-Preis ◽  
Ewa Szram ◽  
Monika Fabiańska ◽  
Ádám Nádudvari ◽  
Magdalena Misz-Kennan ◽  
...  
Keyword(s):  
Trace Elements ◽  
Inductively Coupled Plasma ◽  
Major And Trace Elements ◽  
Water Soluble ◽  
Coal Waste ◽  
Thermal Activity ◽  
Inductively Coupled ◽  
Waste Dumps ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

Abstract Many temporary- and permanent reservoirs of water occur on or near coal-waste dumps in the Lower- and Upper Silesian Coal Basins (Poland). Little or nothing is known of the degree to which their water chemistry might reflect (a) reservoir type, i.e., whether permanent or temporary, (b) level of coal-waste thermal activity, i.e., whether inactive or self-heating or burnt-out or (c) region, i.e., whether the dumps are in Upper- or Lower Silesia. To provide some answers, concentrations of selected ions (NH4+, HCO3-, F-, Cl-, Br-, NO2-, NO3-, PO43-,SO42-) were determined by ion chromatography and of nineteen elements (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, P, Pb, S, Si, Sr, Zn) by inductively coupled plasma mass spectrometry (ICP-MS). The data allow a number of the following observations. When permanent reservoirs are considered, there is a clear relationship between concentrations of ions and major- and trace elements and dump thermal activity. The highest concentrations occur where the thermal activity is high as inorganic components are transformed into more water-soluble forms. As dump thermal activity shows a regional pattern, it follows also that elemental- and ion concentrations in the dump waters show significant regional differences. In temporary reservoirs, concentrations of ions and major- and trace elements are much lower and any correlations between components less significant than in the permanent reservoirs; these reservoirs exist for too short a time for any balance between coal waste- and water components to be established.

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