scholarly journals Coupled Substitutions of Minor and Trace Elements in Co-Existing Sphalerite and Wurtzite

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 147 ◽  
Author(s):  
Allan Pring ◽  
Benjamin Wade ◽  
Aoife McFadden ◽  
Claire E. Lenehan ◽  
Nigel J. Cook
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Significant Variation ◽  
Inductively Coupled ◽  
Trace Element Chemistry ◽  
Icp Ms ◽  
Two Samples ◽  
Coupled Substitution ◽  
Plasma Mass Spectrometry ◽  
Growth Zoning

The nature of couple substitutions of minor and trace element chemistry of expitaxial intergrowths of wurtzite and sphalerite are reported. EPMA and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses display significant differences in the bulk chemistries of the two epitaxial intergrowth samples studied. The sample from the Animas-Chocaya Mine complex of Bolivia is Fe-rich with mean Fe levels of 4.8 wt% for wurztite-2H and 2.3 wt% for the sphalerite component, while the sample from Merelani Hills, Tanzania, is Mn-rich with mean Mn levels in wurztite-4H of 9.1 wt% and for the sphalerite component 7.9 wt% In both samples studied the wurtzite polytype is dominant over sphalerite. LA-ICP-MS line scans across the boundaries between the wurtzite and sphalerite domains within the two samples show significant variation in the trace element chemistries both between and within the two coexisting polytypes. In the Merelani Hills sample the Cu+ + Ga3+ = 2Zn2+ substitution holds across both the wurztite and sphalerite zones, but its levels range from around 1200 ppm of each of Cu and Ga to above 2000 ppm in the sphalerite region. The 2Ag+ + Sn4+ = 3Zn2+ coupled substitution does not occur in the material. In the Animas sample, the Cu+ + Ga3+ = 2Zn2+ substitution does not occur, but the 2(Ag,Cu)+ + Sn4+ = 3Zn2+ substitution holds across the sample despite the obvious growth zoning, although there is considerable variation in the Ag/Cu ratio, with Ag dominant over Cu at the base of the sample and Cu dominant at the top. The levels of 2(Ag,Cu)+ + Sn4+ = 3Zn2+ vary greatly across the sample from around 200 ppm to 8000 ppm Sn, but the higher values occur in the sphalerite bands.

Major- and trace-element composition of REE-rich turkestanite from peralkaline granites of the Morro Redondo Complex, Graciosa Province, south Brazil

2010 ◽  
Vol 74 (4) ◽  
pp. 645-658 ◽  
Author(s):  
F. C. J. Vilalva ◽  
S. R. F. Vlach
Keyword(s):  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Alkali Feldspar ◽  
Trace Element Composition ◽  
Inductively Coupled ◽  
Coupled Substitution ◽  
Plasma Mass Spectrometry ◽  
Compositional Variations ◽  
End Members ◽  
South Brazil

AbstractTurkestanite, a rare Th- and REE-bearing cyclosilicate in the ekanite–steacyite group was found in evolved peralkaline granitesfrom the Morro Redondo Complex, south Brazil. It occurswith quartz, alkali feldspar and an unnamed Y-bearing silicate. Electron microprobe analysis indicates relatively homogeneous compositions with maximum ThO2, Na2O and K2O contentsof 22.4%, 2.93% and 3.15 wt.%, respectively, and significant REE2O3 abundances(5.21 to 11.04 wt.%). The REE patterns show enrichment of LREE over HREE, a strong negative Eu anomaly and positive Ce anomaly, the latter in the most transformed crystals. Laser ablation inductively coupled plasma mass spectrometry trace element patterns display considerable depletions in Nb, Zr, Hf, Ti and Li relative to whole-rock sample compositions. Observed compositional variations suggest the influence of coupled substitution mechanisms involving steacyite, a Na-dominant analogue of turkestanite, iraqite, a REE-bearing end-member in the ekanite–steacyite group, ekanite and some theoretical end-members. Turkestanite crystals were interpreted as having precipitated during post-magmatic stages in the presence of residual HFSE-rich fluidscarrying Ca, the circulation of which wasenhanced by deformational events.

scholarly journals Trace Element Micro-Analytical Imaging via Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)

2011 ◽  
Vol 17 (S2) ◽  
pp. 566-567 ◽  
Author(s):  
A Netting ◽  
J Payne ◽  
B Wade ◽  
T Raimondo
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Unraveling the mechanism and impact of oxide production in LA-ICP-MS by comprehensive analysis of REE-Th-U phosphates

2017 ◽  
Vol 32 (10) ◽  
pp. 2003-2010 ◽  
Author(s):  
Keita Itano ◽  
Tsuyoshi Iizuka
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Comprehensive Analysis ◽  
Inductively Coupled ◽  
Oxide Production ◽  
Icp Ms ◽  
Isotopic Analyses ◽  
Plasma Mass Spectrometry

Oxide interference can be problematic for trace element and isotopic analyses using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).

Petrogenetic significance of LA-ICP-MS trace-element data on quartz from the Borborema Pegmatite Province, northeast Brazil

2011 ◽  
Vol 75 (5) ◽  
pp. 2703-2719 ◽  
Author(s):  
H. Beurlen ◽  
A. Müller ◽  
D. Silva ◽  
M. R. R. Da Silva
Keyword(s):  
Inductively Coupled Plasma ◽  
Border Zone ◽  
Northeast Brazil ◽  
Rare Element ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Coupled Substitution ◽  
Plasma Mass Spectrometry ◽  
Magma Fractionation ◽  
Quartz Core

AbstractQuartz from different zones within five granitic pegmatites of the rare-element class from the Borborema Pegmatite Province in northeast Brazil were analysed for fourteen trace elements using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The concentrations of Li (6—150 ppm), B (1—9 ppm) and Ge (1—23 ppm) in quartz show a positive correlation with Al (30—770 ppm). The concentrations of these elements increase from the border zone to the quartz core of pegmatites of the spodumene or lepidolite subtypes. The Ge concentrations in the quartz core are the highest so far reported in igneous quartz. In the less evolved pegmatites of the beryl-columbite subtype, the Al, Li, B, and Ge concentrations in quartz from all zones remain at the same level as the border and wall zones. The Ti concentrations in quartz from the core of the more evolved pegmatites are below 3 ppm (with Al >250 ppm), contrasting with 7—25 ppm (with Al <280 ppm) in samples from the border and wall zones of the less evolved and more evolved pegmatites. The concentrations of Al. Li, B, Ge, and Ti in quartz are therefore confirmed as good indicators of the degree of magma fractionation and analyses of pegmatite quartz cores can be used for exploration purposes to distinguish pegmatites with high metallogenic potential. Atoms of Li and Al are incorporated into quartz such that Li/Al ranges between 0.75 and 1.0. This suggests a coupled substitution of the form Si4+ ↔ (Li+ + Al3+). The other elements analysed either showed an erratic distribution (e.g. Be and P) or were below the respective limits of detection (Na, K, Rb, Ca, Sr, Mn, Fe) in most samples.

scholarly journals Ecological, Oceanographic and Temperature Controls on the Incorporation of Trace Elements into Globigerina Bulloides and Globoconella Inflata in the Southwest Pacific Ocean

2021 ◽  
Author(s):  
◽  
Julene Marr
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Water Temperature ◽  
Trace Element ◽  
Inductively Coupled Plasma ◽  
Inductively Coupled ◽  
Globigerina Bulloides ◽  
Carbonate Ion ◽  
Icp Ms ◽  
Plasma Mass Spectrometry

<p>Trace element ratios (Mg/Ca, Al/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) measured by laser ablation inductively coupled plasma mass spectrometry plus and test weight and size data are presented for two planktonic foraminiferal species, Globigerina bulloides and Globoconella inflata. These data will be used to investigate the potential of Mg/Ca ocean thermometry and other trace element proxies of past ocean chemistry using these species. Foraminifera were sampled from core-top sediments from 10 sites in the Southwest Pacific Ocean, east of New Zealand, spanning latitudes of c.33' to 54' S and temperatures of 6-19' C at 75-300 m water depth. Mg/Ca in G. bulloides correlates strongly with observed water temperatures at 200 m depth and yields a new calibration of Mg/Ca = 0.941 exp 0.0693*T (r2 = 0.95). When G. bulloides Mg/Ca data from this study are combined with previously published data for this species, a calibration of Mg/Ca = 0.998 exp 0.066*T (r2 = 0.97) is defined. Significant variability of Mg/Ca values (20-30%) was found for the four largest chambers of G. bulloides with the final chamber consistently recording the lowest Mg/Ca values. This is interpreted to reflect changes in the depth habitat towards the end of the life cycle of G. bulloides. Levels of A1 and the micronutrients Mn and Zn in G. bulloides were found to differ significantly between Subtropical and Subantarctic Water masses, suggesting these elements can potentially be used as water mass tracers. No clear relationship between Mg/Ca and temperature was observed for G.inflata. This is interpreted, in part, to reflect the ecological niche that G. inflata occupies at the base of the thermocline, coupled with the impact of heavy secondary calcite which lowers Mg/Ca values. A correlation between size normalized test weight, water temperature and seawater carbonate ion concentration is observed for G. bulloides suggesting a modern calibration that could be potentially applied for paleoceanographic reconstructions of ocean water temperature and carbonate ion concentrations. No correlation between temperature or carbonate ion was found with size normalized G. inflata test weights. However, a bimodal population of G. inflata test weights indicates a possible link between high levels of chlorophyll-a in surface waters and light G. inflata tests. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and solution-based techniques for measuring Mg/Ca in G. bulloides yield compatible results. However, this is possible only when minimal dissolution of test calcite has occurred during the reductive and dilute acid leaching stages of cleaning prior to solution analysis, or, if only the older three visible chambers are used for LA-ICP-MS analysis. LA-ICP-MS analysis is an effective method for measuring trace element/Ca values in foraminifera, especially for small sample sizes, and enables the test to be used for further geochemical analysis (e.g. boron or carbon/oxygen stable isotope analysis).</p>

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