[narrator] There is a general consensus among geologists
that the earth is at least four and a half billion years old.
Fragments of this inconceivably distant past dominate the surface of Big Bend Ranch State
Park.
It’s a place shaped and scarred by eons of geologic havoc.
Shifting continents, volcanoes, faulting and erosion have all at one time or another played
a role in the formation of this landscape.
[narrator] These rocks form part of a giant puzzle that
contains the history of our planet.
Only, the puzzle has a lot of missing pieces.
[splashing water]
[narrator] It’s the job of the geologist to put this
fractured puzzle together.
Dr. Kevin Urbanczyk of Sul Ross State University has been working in and around Big Bend Ranch
State Park since 1984.
[Dr. Urbanczyk] Man this water is just glassy, smooth.
[narrator] For the last few years Kevin has been taking
his students on field trips into this desert region.
The Rio Grande skirting the southern boundary of the park has provided them with a prime
setting for a floating laboratory.
[Dr. Kevin Urbanczyk] The dip out here is the rocks are not flat,
they’re tilted to the west a little bit.
So if you take a series of layers and tilt them to the west, and then cut through them
with a river like this, the river is cut down through these things, then we’re floating
into older and older rocks.
Cause remember the older ones are always at the bottom, you tilt it and then cut it through
horizontally.
As we float, we started in rocks that were about 28 million years old, we floated into
stuff that might be about 29 by now.
[John Alcott] The professor can put everything into perspective
and hit on things that were hit on in class.
And you can actually relate what’s in the classroom to what’s out in the field.
[Shea O’Briant] You can textbook yourself all over the place
but you got to go out and look at it and actually see it.
And Kevin he knows the area real well so he comes down and he tells us everything we need
to know.
I’m finally learning all the formation names.
So yeah, it’s been a lot of fun.
We do probably 10 trips a year with the geology department at Sul Ross.
[Dr. Urbanczyk] So it’s been really successful.
We’ve introduced this canyon in particular to a lot of students, introductory geology
students at Sul Ross who never would have done this, never would have floated through
these canyons.
[narrator] Some of the oldest rocks in the park are found
within the Solatario.
This is called ‘Tesnus Shale’.
[Dr. Urbanczyk] The Tesnus is interpreted as being Carboniferous
in age.
Carboniferous being one of the periods of the Paleozoic about 300 or 320 million years
old or so.
[narrator] Once an ancient sea bottom, this section of
deep ocean sediment was caught between two colliding tectonic plates, approximately 280
million years ago.
When the plates came together the sediment was squashed, tilted and thrust onto the American
continents.
This section of the Tesnus has since been exposed by erosion.
[Dr. Urbanczyk] Ok, this is pieces of this tesnus shale, and
it represents basically solidified or litified mud.
But it’s a sedimentary deposit that’s 300 million years old.
[narrator] Between 25 and 42 million years ago at least
seven volcanoes were active in the Big Bend region.
This is Guale Mesa, the spot where the ash, lava and mud flows from five of those volcanoes
came together.
The actual cones of the volcanoes have long since eroded away, leaving behind only scattered
clues of their existence.
[Dr. Urbanczyk] It’s wonderful that the state has, does
own this property because it provides scientists access to this natural laboratory.
In west Texas in general or access to private property has become restricted, and so we
have Big Bend National Park and Big Bend Ranch really to work with.
[narrator] As the pieces of this fractured, global puzzle
come together, the window to our earth’s history becomes clearer.
Geologists looking through that window at Big Bend Ranch State Park become witnesses
to events that occurred over billions of years.
Meanwhile, this landscape of rock and canyon waits patiently for the next big shake up
of the primeval puzzle.