Hello and Happy National Fossil Day. My name is Anne and I'm the
paleontologist for Grand Canyon National Park. Today I'm going
to talk about some really cool fossils from the Paleozoic rocks
of Grand Canyon.
Now before I talk about the fossils, we've got to understand
the geologic context first.
Now imagine cutting into the Grand Canyon like a cake and
cutting out a slice of that cake. This is sort of what that
slice would look like, showing each layer of rock in the Grand
Canyon. Now the oldest rocks are going to be at the bottom here,
starting with the crystalline basement rocks. They used to be
ancient mountains over billions of years ago, and on top of that
is the Super Group which contain rock layers over 1000 to 700
million years old.
Now, on top of that sits the horizontal Paleozoic rocks.
Now I'll focus on these rocks since they are the ones that
contain the majority of fossils in Grand Canyon.
I'll be talking about body fossils and trace fossils, so
it's important to understand the
difference. Now, a body fossil is essentially the fossilized
remains of an Organism after it dies. So with the body fossil,
you can study the anatomy of the organism and that helps to
classify them. Now with a trace fossil, it is essentially a
record of the interaction between an organism and the
sediment it was walking around
in. So with trace fossils you can study the behavior of an
organism when it was alive. Just like this locomotive trees where
it shows a horseshoe crab walking along the sand and its
footprints are left behind, so it's footprints. Are the trace
fossil, whereas the body fossil is the horseshoe crab itself.
Now acknowledge E is the study of trace fossils and trace
fossils are classified a bit differently than body fossils.
They're classified based on their behavior, the behavior
that they represent. So that's going to be a completely
different classification than body fossil classification.
Now, since I'm focusing on the Paleozoic, I'm going to start at
the lowest formation and work my way up to the youngest one.
So we're going to start at the oldest, which is the Cambrian
period. And this is the Tonto group that represents the
Cambrian period in Grand Canyon.
And that auto group is about 510 to 500 million years old.
And it consists of three different formations,
the Tapeats sandstone, the bright Angel shale,
and the mob limestone.
Now I'm going to focus on the Bright Angel shale since it
contains the majority of Cambrian fossils here.
So this is what the Bright Angel shale looks like in the Canyon.
You can see that it forms somewhat of a slope with a few
exposed cliffs, but when you look at the rocks closer up,
they can actually be quite beautiful and colorful. Just
like this picture here.
Now, the Tonto group represents a very shallow
ocean, and this is sort of the shallow ocean that we
envision as paleontologists when we think of the
Cambrian and so. These are the types of creatures that
were roaming around in this ocean at that time.
So here's an example of some of those creatures. Now these are
trilobites. Trilobites are an extinct group of marine
arthropods that were among the earliest organisms to appear in
the fossil record, and they were the first organisms to develop
eyes. So here are just some examples of the trilobites we
find in the Bright Angel shale.
This one up here is sort of the larger ones that we find Glosso
pleura Mckeei. Here are some smaller ones, called in
Ehmaniella basilica, and these are just a few of what the
type of trilobites that we actually find.
Now, here are trilobite trace fossils. Now some of the
trilobites that we just looked
at. Could have made some of these trace fossils.
Cruziana is a common trace fossil that represents a
trilobite moving along the sea floor. Each of these
lines or striations represent the trilobite appendages as
it's moving and burrowing in the sediment.
Rusophycus is another common trace resembling
a trilobite resting in place in the sediment.
So the trilobite would sink its legs into the sediment and
borough in place until it's completely covered except for
maybe its eyes so that I can see what's going on.
It may do this to take refuge during a storm, or potentially
to hide from predator.
Now here's another trace fossil that we find in the Bright Angel
shale and this one is an arthropod trackway. So
essentially an arthropod was walking along the surface of the
sea floor and made these
footprints. Uhm, an example of what might have made this is
this arthropod called Tegopelte gigas
And we know that Tegopelte. It wasn't a trilobite.
It was similar to a trilobite, but it was a soft bodied
benthic arthropod, meaning that it spent all of its time
on the sea floor and it didn't have eyes, and so this is the
sort of trace maker that could have made these footprints.
We don't have the body fossil found in the Bright Angel
shale, but we have the potential tracks to say that
this are the prod may have been around at this time.
Now similarly, here's another trace fossil that essentially
shows a series of parallel lines
or striations. Where some sort of creature in the ocean must
have swooped down to the sea floor and scraped the sediment.
And based on the sizing of these striations in the trace fossil.
It's possible that a creature called Anomalocaris canadensis NOTE Confidence: 0.9797181
could have made it.
Now Anomalocaris was a great predator during the Cambrian
period, and it was known to swim around and catch prey along the
sea floor so it could have created this trace as it was
picking up a trilobite or a worm with its large frontal
appendages. Come and probably scraped the sea floor as it was
doing that with these sort of spikes that come out of its
appendage. And again, we don't have body fossils of
anomalocaris in the bright Angel shale, but it's
possible that the trace fossil tells us that it may
have existed here as well.
Now just this summer, our research group found the
specimen in the brain. Angel
shale. And so far we actually think that it could be some type
of anomalocaris appendage. So it would have been a smaller one
than the one I just showed you, of course, but it potentially
adds to the evidence that Anomalocaris was around during
the deposition of the bright
Angel shale. So we have yet to study this specimen a little bit
more. Identify it it may not turn out to be an anomalocaris,
but that's where we're leaning towards at the moment, so
hopefully we'll get some updates to this in the future.
Now this is what Anomalocaris might have looked like in the
Cambrian oceans, and so it was pretty big compared to the other
creatures. It had its big appendages to use to catch prey,
very ferocious. One might call it the dinosaur of the Cambrian.
Alright, we're going to jump right into the Redwall
limestone, so we're moving up through geologic time. We went
from about 500 million years to now 350 million years in
the Redwall limestone.
Now this is what the Redwall looks like in the Grand
Canyon. It makes up most of Marble Canyon and it often
forms this major Cliff that appears red, but the rock
itself is actually Gray in color, so the red appearance
just comes from iron oxidation, similar to a rusty
nail.
And the Redwall limestone also represents a vast ocean.
Only this ocean was slightly deeper with different kinds
of creatures.
So these are some of the fossils we find in the Redwall, corals
and these are very similar to the corals that you think of
today. There's different kinds of corals that you can see
here, but they all represent, similar to the kinds that we see
in modern day times.
Another fossil we find in the Redwall are fenestrate
bryozoans. Now, a bryozoan fossil is somewhat like an old
abandoned apartment complex, in which all these millions of
individual organisms once lived
together. And so each apartment in this whole apartment complex
is called as uiam and it housed this tiny little organism called
zoo it. And the zoo is were no bigger than one millimeter.
And each zooid pops out of its apartment just like this picture
shown here. These are the individual apartments or Zooid.
And the zooid pops out here.
To filter feed on plankton or other microscopic organisms
floating by using its tentacles to bring the water to its mouth.
And so these are the fenestrate bryozoan. And each of these Zooid
and are represented in these little sort of bumps that you
see here in the fossil.
Here's another interesting
fossil. And how these are called nautiloids, but these nautiloids
are quite rare because they are or the conic.
Meaning that they were long and strict. As you can see here, and
this is different than the typical coiled nautiloid that we
think of. Uhm?
Now, each of these chambers that are separated by septa.
Some are made of calcium carbonate and they were
used to control the buoyancy of the creature,
so it allowed the creature to float through the water
and catch prey with their tentacles and they could
even move fast or slow depending on where they
move. The water versus air within their chambers.
And this is the fossil that we find in the Redwall
formation. You can see this as a regular ruler, so this
is quite a big fossil.
Now jumping into the Pennsylvanian Permian periods were
going to sort of lumped together. The Supai Group and
the Hermit Formation, so we're at about 320 to 280 million
years old. And the picture on the left shows what the Supai
group looks like in the Grand Canyon. And it consists of four
separate rock formations.
And then on top of that is the
Hermit formation. And the picture on the right shows what
the Hermit formation looks like as far as what the rocks are
actually look like.
Now this is what all of those rocks sort of represent as far
as the paleoenvironment, we had a coastal terrestrial
environment, lots of rivers and swamps and coastal regions.
Containing many different kinds of extinct plants,
insects started to show up. We get reptiles. Many
different creatures are represented in the rock.
So starting with the Supai Group, the Manakacha
Formation is one of the lower formations at about 313
million years old, and this is a picture of me sitting next
to a reptile trackway that was found in the Manakacha
Formation.
Now this was studied and there's a scientific paper on it. We do
know that there are other trackways within the Supai group
that may be older than this, but this is technically the oldest
vertebrate trackway that's officially been reported from
Grand Canyon, so it's it's pretty exciting and we're hoping
to find more in the future.
Now I'm gonna dive into the Hermit formation because Hermit
really contains a lot of the really interesting fossils that
we like to talk about. So starting with some of the
insects we find, this is a
dragonfly wing. And it's called
Typus whitei. And this is the rendition of what the
dragonfly might have looked like about 280 million years
ago. Now keep in mind that this scale bar here is only a
centimeter, so this wing was very large. This dragonfly
had to have been extremely large, so a lot of these
insects were pretty big during this time.
Now here is one of our favorite plant fossils here on the left
called Supaya. Now these types of plants fossil plants are
calledPteridosperms. They're often referred to as seed ferns
because they sort of look like a Fern in the fact that they have
ferns, but they're different from ferns in that they produce
seeds instead of spores.
So they're not actual true ferns. They're
called Pteridosperms.
Now, plants were really important during this time
because they released a lot of oxygen, at least 9%
more than we have today.
Here's another example of a plant fossil we find in the
hermit formation. These are horse tails extinct. Of course,
these are called Sphenophylum
gilmorei. And this is actually an extinct UM
horsetail **** over here on the right is a modern
horsetail, so similar to what it could have looked like.
Perhaps the leaves were a little bit thicker back then.
They kind of look a little bit like flowers, but they're
definitely not flowers. Flowers only evolved much
later in geologic time.
But you can see that the stem actually goes down through the
rock. So what we're looking at are these radiating leaves
that come out of the stem. It's really interesting.
Now lastly, we have this plant called Walchia and
this is a conifer plant very similar to the conifers that
we know of today and and a lot of times will even find
just pieces of the conifer branches preserved in algin.
And then this is a picture of what, Walchia might
have looked like back during the Permian Times.
Now jumping into the Coconino sandstone, I put a picture of
the Namib Desert because it sort of represents what the Coconino
sandstone might have looked like. It was essentially a sand
dune sea, so sand as far as the eye can see and we can see that
in the rocks with the cross bedding of each sand dune.
And so the main fossils that we find or I should say, the
most common that we find in the Coconino are reptile,
trackways and so here are different footprints of
various sizes of reptile footprints that we find, and
some of them are are much bigger and some of them are
much smaller.
Now this one is one of the bigger ones that we've found.
It's also been well studied. It's called Ichniotherium sphaerodactylum NOTE Confidence: 0.9467577
. Now each of these footprints are about the size of
my hand. And it was thought to have possibly been made by an
amphibian like reptile, called a diadectomorph. These are sort of
what the diadectomorphs might have looked like in the
Coconino. They sort of look like these Komodo Dragons.
Now, in addition, we also get invertebrate tracks in the
Coconino sandstone, such as these spider tracks on the left
or these scorpion tracks on the right. Now these spider tracks are
sort of little divots in the sediment, and they have these
groupings of four on each side that represent the four legs on
each side of the spider. This is just a picture of a modern
spider. And then over here to the right we have three little
divots. Kind of come in at an angle, sort of in a V shaped
angle representing just these three legs on either side of the
scorpion. I'm sort of walking at this particular angle.
Alright, now jumping into the Kaibab Formation. Now this is
the rock formation that forms the rim of Grand Canyon and this
is the Permian Ocean. This is sort of what represents the
creatures in the Permian Ocean. We have sharks, fish,
cephalopods, even shrimp and crinoids, all kinds of different
creatures in this ocean and we're at about 280 to 275
million. Years at this point.
So starting with these rugose corals, these are an extinct
group of corals.
And they have this radiating septa that you can see
inside of the coral.
And when these corals were alive essentially, they're
pointed part where it was anchored into the sediment, the
sea floor. And this way their tentacles faced
upwards and would take in any sort of microscopic
organisms and and feed on them using those tentacles.
And now these rugose corals.
I'm shown here represents some of the last of its kind because
they all went extinct at the end of the Permian which was about
250 million years ago.
Now these are sponges, fossilized sponges found in the
Kaibab limestone. And they sort of have this brainy kind
of texture in the rock that shows sort of the skeleton of
the sponge preserved.
But sponges are really interesting. They're among the
simplest and earliest multicellular organisms to
evolve on Earth.
And they've still managed to remain successful today, just
like this modern sponge. And what's interesting is that this
this person is sort of.
Uh, spraying some harmless die around the perimeter of
the sponge and the sponge actually takes in the current
from around it.
Takes in from its body and then expels its waste out of the top,
which is called the osculum.
And so technically, sponges sort of inhale their food.
From their bodies.
And I just thought that this video was really cool
to show how dynamic sponges actually are. Because
they're they're sort of looked down upon. They're
really simple creatures, but they're actually really
interesting and very cool.
How vertebrate material is actually not well known in the
Kaibab limestone compared to the marine invertebrate fossils
And. We see it just a variation of different kinds of
fish teeth. Essentially, we have a rounded tooth mainly for
crushing clams. We have a tooth plate that shows individual
teeth within it. We have this tooth here. That kind of looks
like the typical.
The typical tooth that you might find in the ocean.
And then we have this kind of strange looking tooth here
called the Megactenopetalus
Kaibabanus. And this is actually what it looks like
here. This is what the actual tooth looks like and these teeth
come from. A fish called the Petalodontomorph. Now these
are a group of cartilaginous fish that are more closely
related to today's living ratfish, and I have a picture
here of a modern ratfish and these are all sort of.
Pretty pretty closely related to sharks as well, but they're not
quite sharks now. What's interesting about this this
particular specimen? Is that this fish had these two teeth
just one tooth for its upper jaw and one for its lower, and so
each tooth was specialized with the upper tooth having these
jagged rectangular cusps to grip, pray, and then the lower
tooth had this single straight razor edge tooth so that it
could cut through chunks of flesh. So this was kind of a not
quite a shark, but definitely.
Not a fish that I would want to swim next to.
Alright, that concludes UM looking at are fossils today. I
just want to point out, but if you find a fossil, make sure you
leave it there once. Once you take it out of context, it's
really hard to study, so if you could just take a picture of it,
get some GPS coordinates if you can. If not, just try to get a
good description of where you found it and email that
information to me. Hopefully I can go out and look for that
fossil. And identify it for you and I'll, I'll keep you up to
date on any sort of science that comes with it. So definitely do
that. If you find a fossil in Grand Canyon National Park.
And lastly, I just want to mention that science outreach
communication is very important to us and so you can find us on
social media. Grand Canyon Paleontology for our Facebook
and we also have an Instagram Grand Canyon Paleontology so
please follow us and you can get more information on new
discoveries and more.
Alright, thank you so much for joining me. Have a great day.