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Posts Tagged ‘microstructure’

Hard to believe, but this is my 100th post.   I thought about doing something serious, but honestly, let’s just go with what has been successful for me: garnets throughout my geology career

Garnets in plane light from the Northeast Kingdom of Vermont (BA research):

ERG-25b from the Cow Mountain region of Vermont; garnet inclusions are clearly at an angle to the dominant biotite-muscovite foliation in the rock

Garnet back-scattered electrons (BSE) image from the Connecticut portion of the Bronson HIll terrane (MS research):

BSE image of 99ERG07c

Girl Scouts participating in a Rocks Rock badge workshop (Western Kentucky University, 2002).   We ran the workshop in conjunction with both the Campus Girl Scout troop & the Geology Club the year I taught at Western.

Juniors (4th-5th graders) examining a garnet schist for the rock ID portion of their badge

Wavelength dispersive X-ray spectroscopy (WDS) images from a sample from Payer Land in northeast Greenland (or the PhD project I didn’t end up working on):

WDS mapping of 438965. Garnets are green in the Fe map, blue in the Mg map, and very light in the CP.

In-situ picture of the rocks I did work on for my PhD from Alp de Confin in Switzerland:

bimodal garnet sample that contains kyanite (hard to see without direct sunlight in these samples) from the Adula Nappe

Outcrop photo from a 2007 Vassar field trip to Gore Mt in New York:

amphibole-pyroxene-garnet-plagioclase wall in the upper quarry at the Gore Mt mine

When I taught at the University of Pittsburgh at Johnstown, I started blogging.   At that time I started posting about photomicrographs, including one post about the “jellybean” mylonite from Payer Land.   Hmm, mylonites & garnets together 🙂

Garnet "fish" from the jellybean mylonite.

I started this blog when I moved from UPJ to Gustavus in the summer of 2010.  Over the course of the year, I posted several times during the year about garnets, but the most memorable to me is my summary of the 2010 GSA session in Colorado entitled “Garnet and Its Use in Unraveling Metamorphic and Tectonic Processes”.   Since I didn’t have any pictures to post the first time around, let me just say that garnet research is alive, well, and going in a multitude of directions according to that session.

And last summer I moved back to the Boston area.   Because I’ve only been teaching physical geology & solar system since moving, garnets haven’t come up much in conversation here recently.   In fact, my only garnet-related post was my submission to AW #43 earlier this week.   I obviously need to work on that!

pen & ink drawing of garnet gneiss from Best (1983)

So that’s a 100 posts.   Let’s hope I pick up the pace a bit, add a few more garnets, and hit 200 in less than 18 months 🙂

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Callan posted a blog this morning about the Champlain Thrust (sidenote: having gone to Midd as an undergrad, I have fond memories of the outcrop he describes in the post).   One of the pictures was a close-up of a vein with a distinctive fabric that was puzzling.   The image reminded me of a figure from Passchier and Trouw (2005), so I suggested that maybe the vein was due to antitaxial growth (straight fibres that indicate a mean displacement direction of the vein wall rocks) during simple shear.   Here’s the image:

Fig. 6.7, Passchier & Trouw, 2005

Yes?  No?  Other ideas?

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