Hello and welcome to Grand Canyon National Park.
Because I am at a safe social distance from others around me,
I can lower my mask and speak to you more directly.
My name is Ranger David and we have Ranger Miren,
Rachel and Kevin behind the camera helping me today.
I am standing at the large, stone Bright Angel Trailhead sign on the rim of the canyon.
Today we will be doing a virtual rim walk
along the portion of the rim trail off of the Hermit's Rest road.
On this map you can see the eight stops we will make starting here,
and ending at Powell Memorial Point 1.7 miles or 2.8 kilometers up the trail.
We will be sharing some human history of Grand Canyon and what makes this the grandest canyon of them all.
It's another great day here at the canyon. Let's get started!
*Upbeat music plays*
Our first stop is at the Bright Angel Fault where our trail takes a dip.
This depression in the landscape, created by an ancient crack,
continues across the canyon like a giant trough,
elevating one side of the rock layers 200 feet above the other.
During this walk I will be discussing geologist Wayne Ranney's
five independent factors that make this the grandest canyon of them all.
The first factor is the thick stack of stratified rock that we find here at the Grand Canyon.
You could describe these layers as pancakes stacked on top of each other.
The youngest rock layer is on the top, it is called Kaibab Limestone
which geologists tell us is 270 million years old.
Where did this layer come from? Millions of years ago this area was at sea level
and was covered by a warm shallow sea. This artist's rendition
of the archaic sea shows an ancient shark
swimming past sea sponges and other ancient types of shellfish called brachiopods.
Over millions of years the limestone was compressed into the layer here today.
There are 11 horizontal layers of different sedimentary rocks
shown on this slide, depicting a cross section of a wall of the canyon exposing the 11 layers.
These sedimentary rock layers stacked together, make up four thousand feet of the canyon's walls.
Let's head up the trail to our next stop!
*Upbeat music plays*
Here I am on the west rim of the canyon overlooking the buildings of the historic village.
We can also see the Bright Angel Trail snaking down the side canyon below us.
Native Americans have been living in and around this area for thousands of years.
Today there are 11 tribes that have a strong association with the canyon.
Unfortunately, National Park Service was involved in the displacement of many of these peoples.
The current locations of these 11 tribes are depicted on the map,
showing the areas surrounding the canyon.
Early pioneers at the canyon in the 20th century included the Kolb brothers.
Ellsworth and Emery Kolb arrived here in 1901 and 1902 respectively
and began a photography business.
They asked Mr. Ralph Cameron if they could set up a tent to use as a photography studio.
Mr. Cameron had laid down mining claims in this area which was allowed in those days.
They later built Kolb Studio, a brown building with the yellow window trim
built quite literally on the edge of the canyon with windows facing the canyon on three sides.
From there they took pictures of the mule riders going into the canyon
on the Bright Angel Trail to sell to them later.
The large brown wooden building with the cupula on top,
behind the Kolb Studio, is the El Tovar hotel.
This hotel, built in 1905, was considered to be the most deluxe hotel west of the
Mississippi River. It had running water, electricity
vegetable gardens and a dairy herd outback.
Now on to our next stop!
*Upbeat music plays*
At this stop we can appreciate the vivid and varied colors of the canyon's rock layers.
These colors vary due to the different types of rock and the mineral content.
We can see brown, red, orange, beige and even a hint of green when we pan into the canyon.
The vivid and varied colors are the second factor that make Grand Canyon one of the seven
natural wonders of the world. The only canyon and the only wonder on
the North American continent from that short list.
Let's find out the third factor at our next stop!
*Upbeat music plays*
We have talked about the layers of very old rock here
at the canyon, and how this area used to be at sea level.
60 million years ago, two tectonic plates collided.
The Pacific Plate collided with the North American Plate
lifting it up and creating the area known as the Colorado Plateau.
Today on the south rim we are at seven thousand feet above sea level.
This is a map that shows the areas that rest on top of the Colorado Plateau.
The plateau extends from western Colorado, southern Utah, western New Mexico and northern Arizona.
The uplift of the plateau was so huge that the rock layers of the canyon remained relatively horizontal.
The uplift is our third independent factor. Let's continue on up the trail!
*Upbeat music plays*
At this spot on the rim, we have an expansive view of the canyon.
We talked about the colorful rock layers, but could we see them if we're in a more
temperate climate with much more vegetation?
The fourth independent factor is the semi-arid climate here in northern Arizona.
Within the park there are five life zones. With very little precipitation and lack of rich soil,
very little vegetation covers the canyon walls.
There are beautiful canyons elsewhere on our planet,
but some of their walls are hidden by vegetation.
Here we are able to see the beautiful exposed rock layers.
Looking down into the canyon, the Bright Angel Trail continues down
through Indian Gardens, which is a patch of green oasis in the
otherwise sparsely vegetated canyon. The green patch is due to leafy
cottonwood trees that shade the backcountry campground there.
It is a four and a half mile hike to Indian Gardens and another three
and a half miles to the Colorado River.
At our next stop we can see a little bit of that Colorado River.
*Upbeat music plays*
Here at Maricopa Point we have a view of a small green blue sliver of the Colorado River.
There are many other areas with viewpoints of much more of that beautiful river.
I have mentioned four out of the five independent factors that make this the grandest of canyons.
Let's review the factors, and they are: layers of sedimentary rock stacked on
top of one another, vivid and varied colors, uplift of the Colorado Plateau
and we are in a semi-arid climate.
The fifth factor is the Colorado River.
Geologists tell us the river has been carving the canyon for about 6 million years.
That tells us that we have old rock but a young canyon in geologic time.
The Colorado River is currently controlled by the Glen Canyon dam
approximately 100 river miles upstream.
From here it may not look like a powerful river, but this photograph
of a commercial raft, maneuvering through those huge splashing rapids
gives you a better understanding of the power of the Colorado River.
There are other rivers in a desert environment powerful enough to have carved a canyon.
This includes the Nile River in Egypt
and the Tigris Euphrates rivers in Iraq.
However, the areas these rivers rest on were not uplifted.
You must have uplift for a river to carve a canyon.
Here at Maricopa Point there is also human history.
Over the rim we can see the remains of the Orphan Mine.
John Hogan came west seeking his fortune in the late 1800's.
He filed a mining claim here and started mining copper.
If we look over the rim we can see the metal remains of the mine's head frame
and a large hole in the rock, the old entrance to the mine.
Eventually Hogan's interest turned towards the growing number of visitors
and he built the Grand Canyon Inn on the rim.
Here are two early 1960's photos of the inn,
a wooden barn-like building right on the canyon's edge
with a small pool that looked like a water-filled balcony.
That looks so refreshing on a hot summer day.
The inn existed from 1936 to 1966 but Hogan sold his mining rights in 1946.
In 1951 uranium was discovered in this very spot.
A new shaft was drilled into the rim to increase production of the ore.
The mine existed until 1966.
It's hard to believe that uranium was mined once in one of your national parks.
As we walk to our final stop, we will pass by a fenced-off area on the canyon side of the path,
that has not been declared safe for us to enter due to the old uranium mine.
*Upbeat music plays*
We're at the memorial to John Wesley Powell,
a large pyramid-shaped structure built out of limestone.
The steps of the memorial lead to a view of the canyon and to a plaque dedicated to the great boatman.
Powell was a self-taught geologist who, in 1869, led an expedition starting at Green River Wyoming
down the Colorado River to document this area.
Before his expedition this area of the southwest was labeled the "Great Unknown"
on maps of what is now the lower 48 states.
This expedition quickly turned into a fight for survival when one of the four wooden boats,
carrying much of the food supply and geologic instruments was lost in a rapid.
After three months on the river, the expedition reached a small settlement down river from the canyon.
By then, only five of the nine crew members remained.
In 1872, Powell returned to better document the canyon and the river.
We have now discussed a little geology and human history of the Grand Canyon.
And the five independent factors that make this canyon the grandest of them all.
There is much more to learn and appreciate here,
I hope you can visit and explore Grand Canyon in the future.
It is truly a natural wonder. Thank you for joining me today!
*Upbeat music plays*