Welcome to field trip Friday! My name is
Ranger Christy Fleming and today we are
filming from Horseshoe Bend in Bighorn
Canyon. We going to talk about
geology today. Today we are at horseshoe bend. How many of you at your house
have a growth chart? When you look at
your growth chart that basically tells
you the different things that have
happened in your life and how tall you
are getting. Well here a Bighorn Canyon
this mountain behind me is kind of
like our growth chart. If you look at it
you'll notice there's a red band. That
red band is the chugwater formation. If
you look closely you'll also see just
above the red band there's kind of a
gray color band. That is the Gypsum Formation.
You look above that, you see kind of a
yellowish color band. That band is the
Sundance formation. The next formation
you kind of see that ridge there? There are two ridges towards the top and between those two ridges is the Morrison formation.
And at the very top we just see the bottom of the clover leaf formation.
Which is prior conglomerate.
Now some of you may know a conglomerate
is when you squish a whole bunch of rocks together. So it is a solid platform but it's rocks squished together.
Now if you were gonna
go looking for different fossils in the
sundance formation you would see these
fossils. This fossil right here is called
the crinoid and if you look at it it looks
like a star. This is a remnant of a plant
this is actually the stem of the plant
and then it had big leaves on top of it.
So if you look it's segmented
oftentimes you find these in ant ant hills.
The next one that you might find
in the Sundance formation is the gryphaea.
Gryphaea are basically a historic
clam. If you look at it you can tell that
this is maybe where it would have closed
and opened right there.
Sometimes these are also called Devils toenails because they look like it toenail.
Kind of gross but true. This one
is a belemnite. Basically this is a
fossilized squid. So this part, this
bullet looking part, is the body and then
it would have had its tentacles off of
the back. So this Horseshoe Bend area, you may
wonder why we can see this timeline here? Why do you think that is? Here we are surrounded
by water there's a little bit of wind.
Why do you think that we can see the
different layers? I bet some of you have
already guessed that it's from erosion.
The whole Bighorn Canyon area was
created by erosion. At Horseshoe Bend we see it here. At Devil's Canyon and
further up the lake into the canyon we
see it all the way through. That's what
created the canyon itself. Let's do a
little activity here...
maybe talk about how erosion works. So
this is an easy one to replicate at
home if you want to try it. You don't
necessarily need a lake, but if you have
an area where you have water and maybe
kind of a sandy beach area, you can
definitely try this at home. We're gonna
do two different activities, one we're
gonna look and see what happens when you have a river that winds and we're gonna
look and see what happens when you have a river that's pretty straight. So you
have your water, your cup so you
can get water, you go down to the water's
edge or if you have a sandbox that you
want to do this in you can do it in the
sandbox as well, but you just create a
winding river. Now with the winding river
we're kind of in a rocky area so because
we're in a rocky area that's going to
give us some different outcomes here, but you take the water, and you pour it at
the upper part of your river, and if you
pour it slowly it goes along down in the
river. But if you look here, you will see
that it's discoloring as it's going in.
Do any of you know what that is?
So that is silt. So as you pour the water
in it's moving the finer dirt down into
the water. Here at Horseshoe Bend that
has created a little bit of a problem
this has a big bend in it so as the
water comes in here that silt settles
out which actually raises the amount of dirt underneath the water,
which makes it harder to get
boats in at different levels, at lower
levels. So that can be a problem but it
also is what creates a lot of the
wetlands like in the coastal areas, so it
also can be good. If you poured the water
in a river a little faster you will see
that basically the river channel
doesn't hold up as well. So it starts to
it can start to braid out, it can start
to it can start to push the banks out, so
when you look at a river, river channels
change over time, they braid they change
directions, sometimes it's floods that do
that, sometimes it's ice jam. So we're
just coming out of ice jam season and
going into spring.
The other thing that can
happen, is you can put up a barrier. When
you put up a barrier, like a dam, you
create an area where water can't get
through as well and it pools. So you can
have natural dams and you can have
created dams, like the dam that we have
on the Bighorn River here, that creates the Bighorn Lake, Yellowtail Dam.
So we've kind of looked at the different
ways the water goes through. Let's look
at if you just had something straight.
How would that change? How do you think that would change?
So if you just have like a
straight river channel
the water just pretty much goes straight.
If you keep pouring water to it,
it eventually gets wider, but you can still
see the silt.
So, through this experimentation, hopefully you guys can see how Bighorn Canyon was created
with erosion. Here is our our
growth chart and there's layers above
the clover leaf formation that have been
gone, but that you can still see at
Devil Canyon overlook. I hope that you
guys will join us next time for field
trip Friday. Maybe we'll go to a historic
ranch next. Thanks and have a great day.
If you have any questions or comments,
please put them in the comment section
below and we'll answer any questions you
have. Have a great day.
