I started working in Guatemala in 1984.
I was originally
drawn there by the finding of
jadeite jade there.
The curiosity extended the questions of
"where did this stuff come from?" and "how did
it form?".
It's really turned into a much broader
earth system study of
trying to understand
how the earth works.
The 2010 and the ______
Foundations
expedition
to Guatemala
was to go to central
Guatemala to investigate a
variety of geology related to my
research,
what's called the Guatemala suture zone,
which is the boundary between the North American
tectonic plate and the Caribbean
tectonic plate.
It records how the Caribbean moved into its present location.
We went
to a place we'd never been before
in far eastern Guatemala, towns of Jocotan and Camotan,
where a colleague of ours told us, "Oh, I 
found some rocks there"
that we would call an ophiolite, is 
basically a piece of c-floor crust
that had been in place on top of the
continent.
This body has not been described in the
geological literature. If you look in the
maps of Guatemala, it doesn't exist.
So, just to be able to go and find something
brand new and try to fit it into the
puzzle of the geology
is important for us to understand
what's going on.
The context for jade in the context for
a lot of the rocks in the valley is
what's known as a serpentinite melange.
What it is is
pieces of the earth's mantle
that have been
hydrated, water's been added to them and
they change their
mineralogy into serpentine,
and serpentine is the host
for most of the action.
The kinds of rocks that we're interested
in. Jadeite is a relatively rare
mineral that forms at high pressures,
pressures that are really only produced
in subduction zones.
Basically subduction zones, pieces of
oceanic crust dive under some other
part of the earth,
and water is liberated from the wet
subducted crust,
and that permeates the overlying crust. Part of what it does is create jadeite,
but the other part of what it does is
create the volcanoes that we see. For
example, all around the Pacific.
There are a lot of little connections
that we're trying to put together
in this research.
The project has gotten larger because
now we're trying to understand "how did
things work there?" and "how did this happen?".
There two belts of jadeite, which don't
make any sense with respect to one
another.
Now we know they have different ages.
One's about 150 million
years old and the other's about
70 years old, 90 million
years old.
They're two totally separate terrains that
are just now pasted next to each
other,
and we still don't fully understand
how that happened.
So a lot of our research now was to
help resolve some of this other geological
puzzle.
Right now we're doing isotropic
geochemistry
and trace element geo chemistry on
these rocks because those trace elements
and their isotopes tell us
"what was the process" and "what was the
composition the fluid".
The wind from the subducted slab, the
same fluid that forms jadeite,
then winds up
making jadeite and then also continuing
on into what becomes serpentinite.
I'd bring back a lot of samples.
I'd bring back every
different type of rock that I found. I'd
study the composition of these rocks and I'd
compare
with rocks from other areas to see what is their region,
if they form in the middle of the ocean, if
they form in the ______, if they form
in a hot spot like Hawaii, or if they form in an arc like the marianas.
So I compare
my data
with localities well known around the world
and we know where they form,
and then I try to explain how they ended
up there.
So it's very exciting. It's like detective work.
Every trip
we learn something new.
Every trip we find
new places where we either we haven't found
jade or we found
rocks the people said were different
than they actually are.
So it's the kind of thing you have to be on the ground. You have to go. You have to
collect. You have to bring rocks back to the museum to
study them in detail. Work with others.
We have a broad collaboration
of people in other universities to
study this and it's also open windows
for their research
and other parts of the world
