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|photo by Rose Lincoln
Q What is it that you would like to get across in this course?
A The basic concept is what I like to call the architecture
of the Earth. That’s not my original phrase—but
it’s a term that aptly describes the discipline. If
you look around at rocks on the Earth’s surface, they’re
not all flat, lying, sedimentary rocks. We find that they
are faulted, or they may be folded-—the layers can be
like soup. How does this happen and what are the implications
for ground-water movement, oil and gas reserves, ore deposits?
And what does that tell us about geologic history? Because,
ultimately, geologists are Earth historians; we try to put
together what’s gone on in the 4.6 billion years that
the Earth has existed. The Earth is like a big three-dimensional
jigsaw puzzle, but it’s not static. It changes through
geologic time. So what you need to work out is how that jigsaw
puzzle has changed.
Q How do you approach the craft of teaching?
A Before all my classes, I come in very early and put all
my lecture notes on the blackboard. This way I’m not
talking with my back to the class. I maintain eye contact;
I can walk around the room and talk to people individually.
If I give them little assignments to do during the class,
there’s a lot more interaction. And the other thing
with all department courses, and particularly with Structure,
is that I have a lot of visual aids, a lot of blocks of layered
rocks that are tilted. I use Play-Doh and clay.
A The students can deform things. They will, for instance,
flatten out Play-Doh on window screen material, and impress
a circle on it. And then they can deform it into an ellipse
and we measure how much strain has occurred. We see in nature
rounded pebbles, for example, that are deformed into pillow-like
elliptical shapes. And, obviously, we work a lot with maps.
I have the students generate their own cross-sections. If
they’re looking at the geology on a map, with the data
that’s given, I want them to draw a section as if they
could cut the Earth at right angles, pull away some of that,
and then, describe what they see.
Q The course description says “study and interpretation,” and
I’m struck by the word “interpretation,” because
it seems that they have to figure out a lot.
A That’s true. This is a “doing” discipline.
It is essential to manipulate data mentally, but then manipulate
with your hands what’s going on. Creating that three-dimensional
jigsaw puzzle that changes through time requires that you
be able to imagine, timewise, what the rocks looked like backward
from what you see, or forward from what you interpret—does
it make sense? To do this, they have to learn to be good observers.
Q And then I suppose you also do go out in the field.
A I do take a field trip out to the Boxboro-Harvard area,
where there are some wonderful outcrops of highly deformed
metamorphic, folded rocks. About 250 million years ago, these
rocks were buried under maybe 15 miles of Earth’s crust.
I also take them up into the Middlesex Fells, where the rocks
are highly fractured. This year for the first time, on spring
break, I’m also offering an optional field trip out
to southern Utah where I do my own research.
Q Do they do a term paper or a project?
A They do a project. I give them air photos of a place shot
at two different angles. The students use special magnifying
stereo glasses to look at the two photos simultaneously, which
gives them a three-dimensional aspect. And then the students
map the whole area, showing the distribution of the rock types.
From their observations, they work out the geologic structure.
Q It sounds sophisticated.
A They’re terrified, and I don’t blame them. This
is when they start saying, “Oh, we can’t do this!” And
of course they can.
Q Someone who is deductive and inductive might do well?
A Students who have an artistic aptitude often can imagine
things in three dimensions more easily, and students who are
double majors in geology and art often do really well because
they’re comfortable conceptualizing. In fact, we hope
all students look at the world differently after they’ve
had a geology course. Sometimes they tell us, even if they’ve
only taken one intro course, that family vacations are never
the same. They’re driving down the highway and it’s: “Mom,
Dad, look at the fault over there!” or “Hey, look
at the folds in those rocks!” And, finally, the parents
are saying, “I guess we got our money’s worth
out of that course!”—LF