scholarly journals Ore Microscopy of the Pegmatites of Keffi Area, North Central Nigeria

2021 ◽  
Vol 2 (5) ◽  
pp. 34-40
Author(s):  
I. Y. Tanko ◽  
K. Dzigbodi-Adjimah
Keyword(s):  
Quantitative Analysis ◽  
Light Microscopy ◽  
Elemental Composition ◽  
North Central ◽  
Wavelength Dispersive Spectrometry ◽  
Reflected Light ◽  
Ore Minerals ◽  
Backscattered Electron ◽  
High Concentrations ◽  
Area North

Investigation of the pegmatites of Keffi area was carried out in reflected light microscopy to determine the texture, elemental composition, and the semi-quantitative analysis of the ore minerals from the three groups of pegmatites identified in Keffi area: the non-mineralised, the intermediate and the mineralised pegmatites. Backscattered Electron (BSE) images and Wavelength Dispersive Spectrometry (WDS) were used. Petrographically the portion which is characterised by profuse albitisation, sericitisation and silicification is also associated with the development of cleavelandite, lepidolite, coloured tourmaline and high concentrations of cassiterite and columbite-tantalite (coltan).The order of crystallisation in the pegmatites is from microcline to quartz followed by (plagioclases) oligoclase to albite and by mica (from biotite to muscovite) then by accessory minerals such as black tourmaline, garnet, beryl and lastly oxides of Sn-Nb-Ta. Sphene, rutile, zircon, apatite, ilmenite, and magnetite appeared to be earliest minerals whilst garnet pyrite and chalcopyrite may be syn-metamorphic. Beryl and coloured tourmaline appear to be of hydrothermal phase.

Reflected-light microscopy of uraniferous bitumens

1992 ◽  
Vol 56 (382) ◽  
pp. 85-99 ◽  
Author(s):  
P. A. Eakin ◽  
A. P. Gize
Keyword(s):  
South Africa ◽  
Great Britain ◽  
Light Microscopy ◽  
Mechanical Deformation ◽  
Mineral Inclusion ◽  
Reduction Reactions ◽  
Reflected Light ◽  
Reduction Mechanisms ◽  
High Concentrations ◽  
Early Alteration

AbstractUraniferous bitumens from Great Britain, Scandinavia and South Africa have been studied by oilimmersion reflected-light microscopy and categorised into those formed either by replacement of preexisting uraninite and pitchblende or by complexation/reduction mechanisms in pre-existing hydrocarbons. The former are characterised by displaying normal replacive textures, and containing high concentrations of non-mineral-bound uranium, or later, occasionally exotic, uraniferous fracturefilling phases. Uraniferous bitumens formed during complexation/reduction reactions display monotonous mineralogies and ordered mineral-inclusion distributions.Radiolytic alteration of uraniferous bitumens induces both chemical and mechanical alteration. Early alteration is marked by the generation of mobile hydrocarbons during 'cracking reactions' with subsequent within-sample migration to form globular bitumens and dendritic interspersions of mineralrich and -poor uraniferous bitumen. Mobile hydrocarbons may act as lubricants during mechanical deformation. Advanced organic alteration is characterised by well-documented increased reflectance around uraniferous grains, and by fracturing of the bitumens.

Solving the mechanisms responsible for organelle behavior in vivo by same-cell correlative light and electron microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 14-15
Author(s):  
Conly L. Rieder
Keyword(s):  
Electron Microscopy ◽  
Quantitative Analysis ◽  
Light Microscopy ◽  
Living Cell ◽  
Light And Electron Microscopy ◽  
Time Behavior ◽  
Dynamic Interactions ◽  
Positive Identification ◽  
Cellular Components

The behavior of many cellular components, and their dynamic interactions, can be characterized in the living cell with considerable spatial and temporal resolution by video-enhanced light microscopy (video-LM). Indeed, under the appropriate conditions video-LM can be used to determine the real-time behavior of organelles ≤ 25-nm in diameter (e.g., individual microtubules—see). However, when pushed to its limit the structures and components observed within the cell by video-LM cannot be resolved nor necessarily even identified, only detected. Positive identification and a quantitative analysis often requires the corresponding electron microcopy (EM).

Tandem scanning reflected light microscopy: How it works and applications

1986 ◽  
Vol 44 ◽  
pp. 84-87
Author(s):  
Alan Boyde ◽  
Milan Hadravský ◽  
Mojmír Petran ◽  
Timothy F. Watson ◽  
Sheila J. Jones ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Focal Plane ◽  
Central Symmetry ◽  
Single Line ◽  
Scanning Microscope ◽  
Reflected Light ◽  
Illuminating Light ◽  
Illuminating Beam

The principles of tandem scanning reflected light microscopy and the design of recent instruments are fully described elsewhere and here only briefly. The illuminating light is intercepted by a rotating aperture disc which lies in the intermediate focal plane of a standard LM objective. This device provides an array of separate scanning beams which light up corresponding patches in the plane of focus more intensely than out of focus layers. Reflected light from these patches is imaged on to a matching array of apertures on the opposite side of the same aperture disc and which are scanning in the focal plane of the eyepiece. An arrangement of mirrors converts the central symmetry of the disc into congruency, so that the array of apertures which chop the illuminating beam is identical with the array on the observation side. Thus both illumination and “detection” are scanned in tandem, giving rise to the name Tandem Scanning Microscope (TSM). The apertures are arranged on Archimedean spirals: each opposed pair scans a single line in the image.

Defects of Planarity of Carbon Films Supported on Electron Microscope Grids Revealed by Reflected Light Microscopy

1994 ◽  
Vol 112 (3) ◽  
pp. 252-258 ◽  
Author(s):  
Marc Schmutz ◽  
Jacques Lang ◽  
Sabine Graff ◽  
Alain Brisson
Keyword(s):  
Electron Microscope ◽  
Light Microscopy ◽  
Carbon Films ◽  
Reflected Light

Hyperspectral reflected light microscopy of plasmonic Au/Ag alloy nanoparticles incubated as multiplex chromatic biomarkers with cancer cells

The Analyst ◽  
2014 ◽  
Vol 139 (20) ◽  
pp. 5247-5253 ◽  
Author(s):  
Sergiy Patskovsky ◽  
Eric Bergeron ◽  
David Rioux ◽  
Mikaël Simard ◽  
Michel Meunier
Keyword(s):  
Light Microscopy ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Human Cancer ◽  
Spatial Localization ◽  
Alloy Nanoparticles ◽  
Human Cancer Cell ◽  
Plasmonic Nanoparticle ◽  
Reflected Light ◽  
Spectroscopic Identification

We report a hyperspectral reflected light microscopy system for plasmonic nanoparticle (NP) imaging, and compare with a conventional darkfield method for spatial localization and spectroscopic identification of single Au, Ag and Au/Ag alloy NPs incubated with fixed human cancer cell preparations.

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