Measurement of whole-rock trace-element composition by flux-free fused glass and LA-ICP-MS: evaluation of simple and rapid routine work

2015 ◽  
Vol 49 (3) ◽  
pp. 243-258 ◽  
Author(s):  
Akihiro Tamura ◽  
Norikatsu Akizawa ◽  
Ryo Otsuka ◽  
Kyoko Kanayama ◽  
Marie Python ◽  
...  
Keyword(s):  
Trace Element ◽  
Trace Element Composition ◽  
Element Composition ◽  
Routine Work ◽  
Icp Ms

Deconvolution of the composition of fine-grained pyrite in sedimentary matrix by regression of time-resolved LA-ICP-MS data

2020 ◽  
Vol 105 (6) ◽  
pp. 820-832 ◽  
Author(s):  
Aleksandr S. Stepanov ◽  
Leonid V. Danyushevsky ◽  
Ross R. Large ◽  
Indrani Mukherjee ◽  
Irina A. Zhukova
Keyword(s):  
Trace Elements ◽  
Regression Analysis ◽  
Trace Element ◽  
Sedimentary Rocks ◽  
Trace Element Composition ◽  
Element Composition ◽  
Silicate Matrix ◽  
Time Resolved ◽  
Icp Ms ◽  
Wide Range

Abstract Pyrite is a common mineral in sedimentary rocks and is the major host for many chalcophile trace elements utilized as important tracers of the evolution of the ancient hydrosphere. Measurement of trace element composition of pyrite in sedimentary rocks is challenging due to fine-grain size and intergrowth with silicate matrix and other sulfide minerals. In this contribution, we describe a method for calculation of trace element composition of sedimentary pyrite from time-resolved LA-ICP-MS data. The method involves an analysis of both pyrite and pyrite-free sediment matrix, segmentation of LA-ICP-MS spectra, normalization to total, regression analysis of dependencies between the elements, and calculation of normalized composition of the mineral. Sulfur is chosen as an explanatory variable, relative to which all regressions are calculated. The S content value used for calculation of element concentrations from the regressions is calculated from the total, eliminating the need for independent constraints. The algorithm allows efficient measurement of concentrations of multiple chalcophile trace elements in pyrite in a wide range of samples, including quantification of detection limits and uncertainties while excluding operator bias. The data suggest that the main sources of uncertainties in pyrite composition are sample heterogeneity and counting statistics for elements of low abundance. The analysis of regression data of time-resolved LA-ICP-MS measurements could provide new insights into the geochemistry of the sedimentary rocks and minerals. It allows quantification of ratios of elements that do not have reference material available (such as Hg) and provides estimates on the content of non-sulfidic Fe in the silicate matrix. Regression analysis of the mixed LA-ICP-MS signal could be a powerful technique for deconvolution of phase compositions in complex multicomponent samples.

scholarly journals Encrustation and trace element composition of <i>Neogloboquadrina dutertrei</i> assessed from single chamber analyses, implications for paleotemperature estimates

2012 ◽  
Vol 9 (8) ◽  
pp. 10615-10644 ◽  
Author(s):  
L. Jonkers ◽  
L. J. de Nooijer ◽  
G.-J. Reichart ◽  
R. Zahn ◽  
G.-J. A. Brummer
Keyword(s):  
Trace Element ◽  
Planktonic Foraminifera ◽  
Trace Element Composition ◽  
Element Composition ◽  
Dominant Factor ◽  
Temperature Changes ◽  
Icp Ms ◽  
Neogloboquadrina Dutertrei ◽  
Crust Thickness ◽  
Outer Crust

Abstract. Crust formation is a common phenomenon in planktonic foraminifera. Because of their different formation mechanism and hence composition, crusts affect the overall test composition and therefore complicate the use of crust-bearing foraminifera in paleoceanography. Such species are often used to estimate subsurface paleotemperatures and although the influence of the crust on the trace element/Ca ratio is recognised, it has not been systematically explored between and within tests. Here we use laser ablation ICP-MS to assess the variability in trace element composition of the crust of Neogloboquadrina dutertrei within individual chambers, as well as the effect of compositional heterogeneity of the crust on whole test chemistry. Compositionally, the outer crust differs from inner layer by lower Mg/Ca and Mn/Ca, but is indistinguishable in Sr/Ca. Crust thickness decreases towards the younger chambers and it may be entirely absent from the last chamber. In contrast to Mn/Ca and Sr/Ca, crustal Mg/Ca ratios show a tendency towards higher values on the younger chambers. These patterns in crust thickness and in crust Mg/Ca indicates that temperature is not the dominant factor controlling crust composition. Temperature estimates based on N. dutertrei, and presumably other crust-forming species too, are therefore biased towards too low values. Through comparison of modern and glacial tests we show that this bias is not constant and that changes in the crust thickness and/or in the Mg/Ca values can spuriously suggest temperature changes.

scholarly journals Encrustation and trace element composition of <i>Neogloboquadrina dutertrei</i> assessed from single chamber analyses – implications for paleotemperature estimates

2012 ◽  
Vol 9 (11) ◽  
pp. 4851-4860 ◽  
Author(s):  
L. Jonkers ◽  
L. J. de Nooijer ◽  
G.-J. Reichart ◽  
R. Zahn ◽  
G.-J. A. Brummer
Keyword(s):  
Trace Element ◽  
Planktonic Foraminifera ◽  
Trace Element Composition ◽  
Element Composition ◽  
Dominant Factor ◽  
Temperature Changes ◽  
Icp Ms ◽  
Neogloboquadrina Dutertrei ◽  
Crust Thickness ◽  
Outer Crust

Abstract. Crust formation is a common phenomenon in planktonic foraminifera. Because of their different formation mechanism and hence composition, crusts affect the overall test composition and therefore complicate the use of crust-bearing foraminifera in paleoceanography. Such species are often used to estimate subsurface paleotemperatures, and although the influence of encrustation on the trace element/Ca ratio is recognised, it has not been systematically explored between and within tests. Here we use laser ablation ICP-MS to assess the variability in trace element composition of the crust of Neogloboquadrina dutertrei within individual chambers, as well as the effect of compositional heterogeneity of the crust on whole test chemistry. Compositionally, the outer crust differs from inner layer by lower Mg/Ca and Mn/Ca, but is indistinguishable in Sr/Ca. Crust thickness decreases towards the younger chambers, and it may be entirely absent from the last chamber. In contrast to Mn/Ca and Sr/Ca, crustal Mg/Ca ratios show a tendency towards higher values on the younger chambers. These patterns in crust thickness and in crust Mg/Ca indicate that temperature is not the dominant factor controlling crust composition. Temperature estimates based on N. dutertrei, and presumably other crust-forming species too, are therefore biased towards too low values. Through comparison of modern and glacial tests, we show that this bias is not constant and that changes in crust thickness and/or in Mg/Ca values can spuriously suggest temperature changes.

scholarly journals Mineralogy, trace element composition, classification of Onello high-Ni ataxite

2019 ◽  
Vol 485 (4) ◽  
pp. 484-487
Author(s):  
K. D. Litasov ◽  
A. Ishikawa ◽  
A. G. Kopylova ◽  
N. M. Podgornykh ◽  
N. P. Pokhilenko
Keyword(s):  
Trace Element ◽  
Trace Element Content ◽  
Trace Element Composition ◽  
Element Composition ◽  
Element Content ◽  
Iron Meteorites ◽  
Icp Ms

The trace element composition of the Onello meteorite is analyzed in detail using SEM and LA-ICP-MS. The following Ni contents of minerals are determined (wt %): 23.0-25.4 in taenite, 5.8-8.8 in kamacite, 22-26 in schreibersite, 44-52 in nickelphosphide, 20.6-21.8 in allabogdanite, and 75-81 in awaruite. In the trace element content, the Onello meteorite corresponds to the IAB group of iron meteorites. Inside this group, it mostly matches the sHH subgroup (with high Au and Ni contents). The presence of allabogdanite in the meteorite indicates the high PT parameters of its formation: >8 GPa and 1000-1400 °C. Thus, the formation of the Onello meteorite is related to impact metamorphism of a parental body of iron meteorites of the IAB group and vinonaites, in which a P- and Ni-rich area underwent melting and further crystallization.

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