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Full-Text Articles in Life Sciences
High Precision, High Spatial Resolution Analysis Of Sulfur Isotopes By Laser Combustion Of Natural Sulfide Minerals, S. P. Kelley, A. E. Fallick, P. Mcconville, A. J. Boyce
High Precision, High Spatial Resolution Analysis Of Sulfur Isotopes By Laser Combustion Of Natural Sulfide Minerals, S. P. Kelley, A. E. Fallick, P. Mcconville, A. J. Boyce
Scanning Microscopy
Laser induced combustion provides a powerful new technique for sulfur isotope measurements in natural sulfides. A high power continuous laser, focused through a modified microscope system onto a sulfide mineral target, produces highly localized heating. The laser beam is focused to a spot 25 μm in diameter at the sample surface. In the presence of low pressure oxygen, temperatures at the centre of the spot are sufficiently high to produce localized oxidation. Resultant SO2 is transferred to a gas source isotope ratio mass spectrometer, where the 𝛿34S can be measured to a precision better than 0.25‰. Sulfur …
The Inorganic Geochemistry Of Coal: A Scanning Electron Microscopy View, Robert B. Finkelman
The Inorganic Geochemistry Of Coal: A Scanning Electron Microscopy View, Robert B. Finkelman
Scanning Microscopy
The scanning electron microscope (SEM), equipped with an energy dispersive X-ray analyzer (EDX), has been widely used to study the inorganic geochemistry of coal. This system was instrumental in establishing that the bulk of most trace elements in bituminous coals are associated with fine-grained accessory minerals. Textural evidence, as observed in the SEM, indicates that many of these minerals are embedded in relatively large organic particles. As a consequence of this association, these minerals, and the elements they contain, can be rafted up into the lighter specific gravity fractions during sink-float separation of the coal. Textural evidence also indicates the …
A Quantitative Technique For Determining The Mass-Fractions Of Authigenic And Detrital K-Feldspar In Mineral Separates, Paul P. Hearn Jr.
A Quantitative Technique For Determining The Mass-Fractions Of Authigenic And Detrital K-Feldspar In Mineral Separates, Paul P. Hearn Jr.
Scanning Microscopy
In studies involving radiometric, isotopic, or chemical analyses of authigenic potassium feldspar (K-feldspar), suitable samples are usually available only in the form of authigenic overgrowths on detrital igneous or metamorphic grains. The analysis of these mixtures often requires a measurement of the relative proportion of each component. To address this need, a technique has been developed which utilizes backscattered-electron (BSE) and cathodoluminescence (CL) detectors together with an image analyzer to quantify the relative proportions of authigenic and detrital K-feldspar in monomineralic separates. Authigenic (low temperature) K-feldspar overgrowths are distinguished from high temperature K-feldspar cores by their lack of luminescence. Computer …