Transcript Day 41

Day 41
Why is the Grand Canyon important to
geologists?
The Grand Canyon itself is only about 10
million years old, but it reveals things that
happened as many as 1.7 billion years
ago. The Colorado River has eroded
through many layers of ancient rock, and
those layers provide clues about what the
area was like when they formed.
Daily Warm-Up Exercises
1
Observe Grand Canyon Rocks
(Part 1, steps 1-15)
Investigation 3
Grand Canyon Rocks
2
Quick Write
Answer the following question in your
journal:
Why are there lines on
the walls of the Grand
Canyon?
Write down all of your
ideas about why the lines
are there.
3
River Miles
Rafters developed a system to identify their
location along the Colorado River. Turn to
page 3 of the Resources Book, and look at
the numbers along the river.
Where is zero?
In the upper right corner of the map.
The numbers stand for miles. Mile zero is
Lee's Ferry, the main starting point for rafting
trips. The other numbers show how far that
point is from Lee's Ferry.
4
Study Sites
Turn to pages 8 and 9. These are two sites in
the Grand Canyon.
Which canyon is closer to Lee's Ferry?
North Canyon
How much further down river is Nankoweap?
32 miles
Use the mile markers to locate both sites on
the Grand Canyon map.
5
Elevation
Page 9 says the river elevation is about 2800
feet. What does that mean?
At that point, the river is about 2800 feet
above sea level
Which location is higher?
North Canyon
At North Canyon, is the river flowing toward
Lee's Ferry or toward Nankoweap?
toward Nankoweap
6
Powell's Technique
a. Drew a sketch of
the canyon wall
b. Collected and
marked rock sample
from that area
c. Labeled his sketch
to show where each
sample was
collected
7
North Canyon
8
Nankoweap Canyon
9
Sketch the Two Sites
 Sketch the canyons on the ws.
 Sketch the North Canyon on one side and
Nankoweap on the other.
 Your paper is labeled with the canyon
names on different sides. Put the right
sketch on the correct side! This is
important later!
10
Record Observations
Examine the North Canyon rock samples
and record your observations.
Examine the Nankoweap samples and
record your observations.
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6
7
8
9
10
color
acid
other observations
11