Transcript Scaling up to mountainous change

Explore p. 650 - 662
 4.
At a rate of 2 cm/second how long did it take
your plate to move across your work table?

About 75 seconds, or 1 minute 15 seconds
 6.
Let’s scale up the velocity from 2cm/second
to see how far the plate moves in a year.
cm/sec
cm/min
cm/yr
m/yr
km/yr
2
120
63,115,200
631,000
631
 7.
Using the rate above (km/yr) how long would
it take your plate to move to different states?
 8.
Tectonic plates move at a rate of 3cm/year.
How long would it take a tectonic plate to move
across your work table?
If the table is 150cm long, it would take 50 years.
 150cm x 1year/3cm = 50 years

S&T #1a: Continents move about 3cm/yr. What step
from #6 has units that are easiest to compare with the
velocity of continents? Why?
 S&T #1b: Is the paper plate’s or continent’s velocity
faster? How much faster?

The paper plate is about 21,000,000 times faster
 63,115, 200 cm/yr / 3 cm/yr = 21,038,400
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Learning
Target: I can distinguish
between uplift and erosion processes
in mountain belts.
 Skills:
I can analyze coral terraces and graph
elevation changes
 I can calculate uplift rates from this graph
 I can compare uplift, erosion, and erosion
half-life

Read Introduction p. 654
 Some vocabulary:
 Glacial period – periods where the overall global climate
is cold. Glacials are characterized by low sea levels and
the widespread extent of ice sheets.
 Interglacial period – periods where the overall global
climate is warm. Interglacials are characterized by high
sea level and a limited extent of ice sheets.
 Radiometric dating - is a technique used to date
materials such as rocks, usually based on a comparison
between the observed abundance of a naturally
occurring radioactive isotope and its decay products,
using known decay rates.

 kya
means thousands of years ago
 mya means millions of years ago
 Work
with your partner to complete P&P
#1-10. p.654-662 (2 days to complete)
 Make sure you answer all questions in your
science notebook.
 Graphs should be done on graph paper and
taped into your science notebook!
 Must get through step 6 today
 HW: Read “Weather to Erode” p. 659 and
take notes! Don’t forget a summary at
the end!
 If
you are planning to take the retest for the
dimensional analysis quiz, the review
worksheet is due today.
 You must schedule a time to take the quiz
either before school, after school, or during
lunch on Monday.
 First,
you used the diagrams of the coral
terraces in Papua New Guinea and Barbados
to create a data table (elevation vs. age of
coral).
 You measured the distance (in mm or cm)
from sea level to the top of the coral terrace
on the sketch.
 You used the scale as a conversion factor to
calculate the elevation in meters. (New
Guinea: 200m/15mm) (Barbados:
50m/11mm)
Then you graphed elevation vs. age.
What did the slope correspond to?
What can you say about the uplift rates of the
two locations?
 (Step
6) Then you began with an uplift rate
of 2.5 mm per year (m/yr), and converted it
first to meters per thousand years (m/kyr),
then to kilometers per million years
(km/Myr).
 What did you find?
 (Step
8) You used the uplift rate of 2.5 mm
per year (m/yr) to calculate how much uplift
would occur in a mountain chain over 1
Million years. (It was helpful to refer back to
your table from step 6).
 You repeated this to calculate uplift over 10
Myr.
 You compared your calculations to the actual
elevation of Mt. Everest (8,850m) over 30
Myr.
 Why are they different?
 (Step
9) You applied the concept of erosion
half-life to see how a mountain chain that is
not being uplifted changes over time.
 How did the mountain profile change?

You should be able to
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use a geologic diagram to determine elevation vs. age
graph elevation vs. age
calculate an uplift rate from your graph
Convert uplift rates from mm/yr to m/kyr to km/Myr
Calculate how much uplift occurs in a given amount
of time, given an uplift rate
Explain why the calculated uplift may be different
than the actual elevation of a mountain
Predict the elevation of peaks and valleys given an
erosion half-life (before and after)
Compare erosion half-lives and discuss why they are
different for different areas
Discuss how erosion and uplift affect mountains