In Petrology class, we spent the whole semester on granites. We read and discussed H. H. Read's The Granite Controversy, and little else. I didn't know what Bowen's Reaction Series was until the next millennium. We never even saw a petrographic microscope, much less looked through one.
Forty years later, I went back to school to get a Master's degree in Geology. I was surprised to find out how little had changed. There was no course in Optical Mineralogy or Petrography. Undergraduate Mineralogy was combined with Geochemistry, and only the rudiments of optical mineralogy were addressed. No Advanced Mineralogy class. No Metamorphic Petrology. One of my professors told me why: It's all about getting grant money. As the old professors have retired, young ones have been recruited who can bring in funding, and that means geodynamics and isotope geochemistry.
None of the other first-year grad students had ever heard of peridotites, and very little was said about them in our textbooks and lectures. But I was interested in peridotites. After all, they comprise most of our planet. So I started reading about them, and took every opportunity to collect samples and have them made into thin sections. I taught myself most of what I know about peridotites.
After I graduated in 2010, I thought I might write the definitive book about peridotites, since I don't think anyone has done that. I started building this blog to organize my thoughts, and soon decided that this is all I have to say for now. The book will have to wait. So, because I've collected quite a few thin sections of peridotites, rather than letting them sit in their boxes, I wanted to share my favorites that illustrate a particular mineral, feature, or process. I hope this blog will be useful to those who want to learn about peridotites, so they won't have to do quite so much of it on their own.
Incidentally, you don't need an expensive microscope to view and photograph thin sections in cross-polarized light. I made my own polarizing microscope a few years ago, when I started grad school. The microscope in the photo is a $200 Observer. I bought a couple of polarizing filters for $20 each, and made a platform for the polarizer out of cardboard. That's my old Pentax film camera in the photo. I now use a Pentax digital SLR. One more thing - the microscope adapter cost $125. Total investment (assuming you have a suitable camera and tripod): $365. I used this setup to make all of the photomicrographs on this blog. I now have a "real" polarizing microscope - a Meiji T3460 trinocular - but I still use this primitive apparatus for all of my photomicrographs.
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