Thin-Section photomicrograph results of Rock samples from Rambi gold Target, Western Kenya
Description
Thin-section of three representative samples was done to sufficiently classify the rocks and grant them the their correct rock ID. Minerals of different kinds that identify with particular rocks are able to be identified under the microscope. Calcite has high birefringence with a high refractive index. Quartz displays low interference colors with a low relief and absence of cleavage. Chlorite is seen to be pleochroic, ranging from light-green to different shades of green with a birefringence of purplish or brown color. Kaolinite is seen with a distinct distorted shape with a first-order interference color in cross-polarized light. Illite is pleochroic and appears pale brown and yellow under crossed-polarized light. K-felspar mineral contains a twinning with a cleavage plane in two directions. Pyrite is typically seen as opaque cubic crystals individual and aggregated into clusters.
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Steps to reproduce
The thin-section samples were taken to the lab, and the laboratory residence ID was given. They were labeled according to the hole ID (1, 3, or 5) and the last 3 digits of the original sampling ID. E.g., RAM1382_Hole number 1 and 382 from a sample of ID, DDA30382. In the lab, the three samples were all cut into different sizes (25-30mm). They were later trimmed and polished using the grinder to the size of the slide (size 1mm by 25mm by 40mm). Further polishing was done using carborandum powder whose grit sizes are 90,100,600 1000 (in mesh) The samples were then mounted over a hot plate using Canada balsam as the adhesive. Viewing was done to check the thickness achieved. The best thickness being 30 microns same as 0.03mm. Different refractive indices of the sections was able to be observed at this thickness helping to describe the birefringence of different minerals. The label of residence was carefully transferred to the slide for correct identification. Examination was done on the samples under transmitted-light microscope, in both plane polarized and cross-polarized light, at magnification ranging from 4X to 400X.
Institutions
- University of Nairobi