[Make sure to expand the photos for better quality!!]
Pictured above are photomicrographs of thin sections from the Manson impact structure (located in Manson, Iowa) seen through polarized light and crossed nickels. The first photo displays what I believe may be a silicate (feldspar, plagioclase) grain that exhibits the parallel striae of planar deformation features characteristic of shock metamorphism. The second photo depicts the annotations that I made to the original photomicrograph to highlight areas of interest. As seen in the second photograph, there is an extinction front captured in this image. Many silicate minerals that experience shock metamorphism after a collision may exhibit undulatory extinction, where the anisotropic nature of the crystal itself is not simultaneously experienced but rather is progressively expressed due to the irregularity created by the massive impact from a meteor. I don’t believe that there are many published photomicrographs of these thin sections, so this is a rare and special treat for anyone interested in geology, microscopy, meteoritics, or the wider field of astronomy. Enjoy! :^) [Please, if you have any comments, suggestions, or corrections for my work, leave them on this post!]
