Thin Section Granites

These are photographs of a thin section of granite magnification 10x perhaps the most common igneous rock we encounter.

Thin section granites.

By comparing the plane polarized light left and crossed polarizer right images we can see that there are three minerals in this granite. Some common rock types as seen under the microscope. Enjoy the videos and music you love upload original content and share it all with friends family and the world on youtube. Strictly speaking granite is an.

Granites can be predominantly white pink or gray in color depending on their mineralogy the word granite comes from the latin granum a grain in reference to the coarse grained structure of such a completely crystalline rock. Photomicrographs of these minerals in thin section from s type granites of the lachlan fold belt are shown in figure 2a and 2b. Granite ˈ ɡ r æ n ɪ t is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Biotite brown grains in plain light and pinkish brown with crossed polars the brown color is due to a property called.

If a mineral commonly has a range of colours it will appear once for each colour. Rocks under the microscope. S type granites can also contain aluminium rich iron and magnesium rich biotites. This means that biotite in standard thin sections rarely goes completely extinct.

Quartz thin section photomicrographs are taken in plane polarized light and cross polarized light and can easily be recognized under the microscope. Within the tables minerals are arranged by colour so as to help with identification. Damage produced during thin section grinding causes speckles of light in the biotite where the crystal lattice has been deformed. Each thin section was first scanned in unpolarized light and then again between two sheets of crossed polaroid film aligned parallel to the thin section edges.

Granites in the slate belt together with those in the shan scarps segment of the mogok metamorphic belt to the west fig. These are photomicrographs very thin slices of rock seen in plane polarised light or between crossed polarisers when the colours seen are produced by interference of light. Originally plane polarized scanning in separate e w n s orientations was attempted to highlight pleochroic variation but this ultimately had to be abandoned due to significant. Biotite metaluminous granite showing a close up of one crystal.