Kurt FriehaufPhotos from Optical Mineralogy

Kurt Friehauf

Traditionally, Optical Mineralogy is supposed to be a training course in how to use a petrographic microscope.  Geologists use pretty specialized microscopes to study rocks, so the learning curve is a little steep at first.  My predecessors used the course also to provide a little math workout for students.  In my class, however, we take the approach that there is already a plenty that needs to be learned - certainly no time for frivolous and abstract math calculations purely for math's sake.  I use my Optical Mineralogy course as a tool for teaching the whole process of field data and sample collection, to sample preparation, to petrographic study.  I think it's important to learn procedures in their context and to keep in mind the big picture.

The Richard-Teabo iron mine problem is deceptively simple at first glance.  There are a bunch of little mine pits in an old mining area.  Each mine pit has piles of rock that most likely represents the rock type at that point if one were to dig down through the soil and glacial till.  The questions are these:
  1. How many rock types are present?
  2. Devise a classification scheme to sort the rock types out.
  3. Is there a systematic spatial pattern to the distribution of different rock types?  (if so, what?)

opticalWorking our rock types at the Richard-Teabo iron mine, New Jersey.  The temperature was well below freezing, which was good because we wouldn't have to worry about getting wet if there was precipitation!


opticalopticalRichard-Teabo -

opticalopticalRichard-Teabo - Dave and Megan are real tigers and get right in there.  This is very good form!

opticalRichard-Teabo - we worked in groups of three to encourage communication skills.  Geologists commonly work in teams in industry, so why not start preparing our work habits right now?

opticalopticalRichard-Teabo - a beautiful, albeit cold day to be out looking at rocks!

opticalopticalRichard-Teabo - the group after a day of study.


rock sawsrock sawsSample preparation in the rock room.  We have several rock saws for ... well... cutting rocks!  Cut surfaces of rocks commonly reveal otherwise hidden features.  Cutting rock samples is also the second step in the preparation of microscope slides (called thin sections). 
Do you know what the first step is?

rock sawsrock sawsLiz likes using a dental-drill like tool to liberate fossils and carve samples (left).  Jon's particularly fond of the Target saw and I have to agree with him - two horsepower makes a mean cutting machine!

rock saws


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