Typomorphic gold features as criteria of placer association with primary gold-silver-type sources (example from Mnogovershinnoye ore placer cluster)

2020 ◽  
pp. 3-23
Author(s):  
Igor Migachev ◽  
Olga Minina ◽  
Vadim Zvezdov
Keyword(s):  
Crystal Morphology ◽  
Gold Cluster ◽  
Primary Source ◽  
Trace Element Composition ◽  
Element Composition ◽  
Primary Sources ◽  
X Ray ◽  
Icp Ms ◽  
Gold Silver ◽  
Comprehensive Study

A comprehensive study of native gold from Mnogovershinnoye gold cluster ores and placers (granulometry, crystal morphology, internal structure, nature of exogenetic transformations, fineness and trace element composition) was performed to define placer association with primary sources. Using ICP-MS method and X-ray spectrographic analysis, new data on geochemical gold features was obtained, which expands and clarifies the evidence of gold typomorphism from a gold-silver deposit primary source and its association with placers.

Typomorphic gold features as criteria of placer association with primary gold-silver-type sources (example from Mnogovershinnoye ore placer cluster)

2020 ◽  
pp. 24-38
Author(s):  
Svetlana Yablokova ◽  
Georgiy Samosorov ◽  
Natalia Pozdnyakova
Keyword(s):  
Crystal Morphology ◽  
Gold Cluster ◽  
Primary Source ◽  
Trace Element Composition ◽  
Element Composition ◽  
Primary Sources ◽  
X Ray ◽  
Icp Ms ◽  
Gold Silver ◽  
Comprehensive Study

A comprehensive study of native gold from Mnogovershinnoye gold cluster ores and placers (granulometry, crystal morphology, internal structure, nature of exogenetic transformations, fineness and trace element composition) was performed to define placer association with primary sources. Using ICP-MS method and X-ray spectrographic analysis, new data on geochemical gold features was obtained, which expands and clarifies the evidence of gold typomorphism from a gold-silver deposit primary source and its association with placers.

Early Palaeolithic bone diagenesis in the Arago cave at Tautavel, France

1999 ◽  
Vol 63 (6) ◽  
pp. 801-812 ◽  
Author(s):  
L. Quattropani ◽  
L. Charlet ◽  
H. de Lumley ◽  
M. Menu
Keyword(s):  
Clay Minerals ◽  
Gamma Ray ◽  
Trace Element Composition ◽  
Element Composition ◽  
X Ray Diffraction ◽  
Human Occupation ◽  
X Ray ◽  
Bone Diagenesis ◽  
Very High ◽  
P Influx

AbstractBones from level G in the Arago cave (Tautavel, Southern France, 450 ky) were analysed using a combination of particle induced X-ray and gamma-ray emission (PIXE and PIGME) and X-ray diffraction (XRD). Human occupation and guano production by bats introduced a large amount of phosphate into the cave and as a result a decarbonated pocket was formed in the sediment, characterized by the dissolution of clay minerals, calcite and bones, and by the precipitation of phosphate secondary minerals. The Al released by clay minerals was reprecipitated as crandallite in the few remaining bones, and as montgomeryite with traces of crandallite in the surrounding sediments. Bones within the pocket have very high levels of Al, Fe, F and Zn and often have ‘diffusive’ type U-shaped concentration profiles. These profiles show that post-mortem uptake of trace elements occurred, and thus that trace element composition has to be used with care in palaeonutritional studies but is indicative of local palaeoenvironment. This uptake is complicated by a large increase in hydroxylapatite crystallinity in Palaeolithic bones compared to modern or more recent ones, as a result of the large P influx which occurred in the Arago cave after the sediment deposition.

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.

Analysis of Biological Elements of Scalp Hairs With Sem-Edx and Tem and its Application to the Hair Comparison

1985 ◽  
Vol 43 ◽  
pp. 120-121
Author(s):  
S. Seta
Keyword(s):  
Crime Scene ◽  
Trace Element Composition ◽  
Element Composition ◽  
Personal Identification ◽  
X Ray ◽  
Evidential Value ◽  
Hair Samples ◽  
Hair Strand ◽  
Blood Grouping ◽  
Scanning Electron

Personal identification of hair samples collected from the crime scene has been principally made on basis of precise comparison of morphological features and the result of blood grouping of hair samples. For the present only ABO blood types can be routinely examined on hair samples, and therefore, other additional informations for the hair comparison have long been required, among which the trace element composition of hairs has been utilized as giving a clue to the hair comparison. Here, scanning electron microscope equipped with energy dispersive X-ray microanalyzer (SEM/EDX), which has been widely used to examine many kinds of physical evidences in forensic laboratories, was applied to the elemental analysis of hairs. Since SEM/EDX enables us to analyze very small amount of sample, it is very efficient in the hair comparison in which each single hair strand collected from crime scenes has its own evidential value. But SEM/EDX analysis of hairs involves the intrinsic problem that trace elements other than sulfur and chlorine are very hard to detect from raw hair samples.

scholarly journals Proton Induced X-Ray Emission (Pixe) Analysis of Meteoritic Microsamples

1985 ◽  
Vol 85 ◽  
pp. 157-158
Author(s):  
R. Wallenwein ◽  
H. Blank ◽  
E.K. Jessberger ◽  
K. Traxel
Keyword(s):  
Interplanetary Dust ◽  
Trace Element Composition ◽  
Element Composition ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Pixe Analysis ◽  
X Ray ◽  
Examination Methods ◽  
The Heidelberg Proton Microprobe ◽  
Cometary Origin

AbstractInterplanetary dust particles (IDPs) collected in the stratosphere are thought to be mostly of cometary origin. They survived heating during their deceleration in the earth’s atmosphere (1). Because of their small size (< 50 μm ) and mass (< 10−7 g) they are difficult to analyse. Special preparation and examination methods have been developed for their investigations (2). We set out to study the trace-element-composition of these particles using the Heidelberg proton microprobe.

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.

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