My friend lately. I still struggle when looking at thin sections, but it’s something I’ve enjoyed: building a visual vocabulary of the work on the microscale.
Here’s some pictures of some lithic arenites we’ve been studying. I took HD video of me rotating the stage on the microscope so I could demonstrate the types of things that you look for when looking at these under thin section, but I got lazy and I didn’t upload them. Essentially, you rotate the stage (where the slide sits) and you look for patterns of extinction (grains change color when rotated, usually dark to light) within grains. As the grain rotates, the light interacts with the crystallographic structure of the minerals resulting in a unique pattern.
I planned ahead very poorly when taking pictures obviously because there is only one grain in this picture that is showing off it’s extinction. In the middle top, you can see a grain that has both white and dark spaces that mix. That is a microcline grain that is halfway between it’s light and dark phase.
This next picture if of a gigantic microcline grain that showcases it’s extinction much more clearly and obviously.
When you see that cross hatched type of texture appear when rotating a slide, you know you have microcline. It’s pretty neat really.
I might upload those videos tomorrow to show it off a little better.
I filed my taxes today, my return will go to paying for school (to avoid late fees on my tuition payments) almost immediately once it’s deposited. Being poor sucks.