Transcript Day 47

Day 47
What are index fossils?
They are the remains or traces of
organisms that lived for only a short time,
but in many places around the world.
Why are index fossils important to geologists?
They can be used to compare the ages
of rock layers. All rock layers that contain
the same index fossil are about the same
age.
Daily Warm-Up Exercises
1
Differential Erosion
(Part 4)
Investigation 3
Grand Canyon Rocks
2
Differential Erosion
Landforms shaped like steps or cliffs are
formed by differential erosion.
This happens when a mountain or plateau
is made out of both soft, weak rock and
hard, strong rock.
The softer rock wears away faster, leaving
behind knobs and cliffs of harder rock.
3
Monument Valley
Can you find Monument Valley on the
Colorado Plateau map? (Pg. 32)
Page 19
This area is famous and has been used in
many movies.
Show video
Daily Warm-Up Exercises
4
Chuar Butte Observations
Turn to page 18 in the Resources book.
This is a picture of Chuar Butte.
Can you find this on your Grand Canyon
map? (Pg. 3)
Use the picture to answer the questions on
the Chuar Butte Observations sheet (page
17)
5
Examples of Differential Erosion
Turn to pages 20-21 in the Resources book.
Choose three images that are good
examples of differential erosion.
Sketch the landforms in 3 images on the
back of page 17 and label it with the name
of the national park you sketched.
Label which layers are harder/stronger and
which are softer/weaker.
Label which layers are limestone,
sandstone or shale.
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