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
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:
- How many rock types are present?
- Devise a classification scheme to sort the rock types out.
- Is there a systematic spatial pattern to the distribution of
different rock types? (if so, what?)
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!
Richard-Teabo - Dave and Megan are
real tigers and get right in there. This is very good form!
Richard-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?
Richard-Teabo - a beautiful,
albeit cold day to be out looking at rocks!
Richard-Teabo - the group after a
day of study.
Sample 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
Liz 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!