Lab 3 Plate Tectonics
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Jacksonville State University *
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210
Subject
Geology
Date
Feb 20, 2024
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docx
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5
Uploaded by AgentMooseMaster1025
Lab 3 Plate Tectonics Required Materials Pencils Colored Pencils Computer with google earth software loaded
Pre- Lab reading and quiz
Read chapter 2 of “Earth Science” ,and review your lecture notes on plate tectonics.
How do lithospheric plates move at a divergent margin? As they move apart, magma wells up from beneath the surface to fill the space left from the diverging plates. Give an example of a present day oceanic divergent margin. mid- atlantic ridge
What features would you expect to find at an ocean- ocean divergent plate boundary? The submarine mountain range plus the creation of a new seafloor, which stretches the ocean basin. Give an example of a present day continental divergent margin.
The Mid Atlantic Ridge divides Iceland How do the lithospheric plates move at a convergent margin?
It happens when plates move toward each other and collide.
Give an example of a present day convergent margin.
The Washington- Oregon coastline of the United States What features would you expect to find at an ocean-continent convergent plate boundary?
San Andreas fault zone of Western North America
How do the lithospheric plates move at a transform margin?
Two plates sliding past each other forms a transform plate boundary. Give an example of a present day transform margin.
United States West coast. The plates move past each other.
In-class lab exercises
Part 1 Plate processes The diagram below is a simplified representation of an ocean-ocean divergent margin
A. Lithosphere
B.
Mid Ocean Ridge C.
Zone of Melting
D. Asthenosphere
Label the oceanic lithosphere, the asthenosphere and the zone of melting, and the mid ocean ridge. Draw arrows on the plates to indicate the directions in which they are moving. Draw a second set of arrows to show the direction of flow in the asthenosphere
What feature would you find at the center of the mid-ocean ridge?
Volcanoes
The diagram below is a simplified representation of an ocean-continent convergent margin.
A.
Oceanic Lithosphere
B. Trenches
C.
Accretionary Wedge
D.
Zone of melting E. Asthenosphere
F.
Asthenosphere
Label the oceanic lithosphere, the asthenosphere and the zone of melting. Indicate the regions where earthquakes may occur
Draw arrows on the plates to indicate the directions in which they are moving. Draw a second set of arrows to show the direction of flow in the asthenosphere. Draw and label the locations of the trench and the accretionary wedge
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The diagram below is a simplified representation of a hot spot.
A. Youngest
B. Oldest
C. Lithosphere
D. Asthenosphere
Draw arrows on the plate to indicate the direction of movement. Label which island is the oldest and which is the youngest.
What information do hotspots like this give us about past plate movements? Hot spots generally stay in one place while the tectonic plate above it keeps moving. So we can measure the past plates.
Part 2 Calculation of Plate movement Look at the map of the age of the seafloor in figure 2.17 of “Earth Science”.
From your initial observation, do you think the Mid-Atlantic Ridge is spreading faster or slower than the East Pacific Rise?
The mid Atlantic ridge is spreading slower than the East Pacific Rise.
Explain why you think this
I think this because we can see lower aged rocks at a further distance from the East Pacific Rise. Looking at the North Atlantic… What age is the seafloor immediately off the coast of NYC?
180 million years old
Using the ruler tool in Google Earth, what is the shortest distance (in km) of the edge of the continental shelf off NYC to the Mid-Atlantic Ridge?
322,478,819.30 = 3224.788193
Using the equation rate = distance / time, how fast had North America moved away from the Mid-Atlantic Ridge (in cm/year)?
1.80 cm/ year
Looking at the East Pacific… South America is moving away from the East Pacific Rise at approximately 8.6 cm/year. Do these rates agree with your initial assumption? Explain why?
Yes, because I was on target for the actual rate.