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We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

Dec 28, 2015

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Griselda Melton
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Page 1: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.
Page 2: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

We know the Earth is broken into 8 major lithospheric plates ….

We know these plates move ….We know there are boundaries between the

plates ….Now, let’s look at the three types of

boundaries in a little more detail . . .

Page 3: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

Lithosphere: Earth’s hard outer shell; divided into plates.

Diverging Plate Boundary: Plates are moving apart as new ocean crust is formed ~ most divergent boundaries are found in the ocean.

The African and Arabian plates continue to rift apart (diverge), with the result that the Red Sea is ever widening.

Page 4: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

Convergent Plate Boundary: Plates moving together/toward each other. Can be subduction or collision; subduction results in the formation of oceanic trenches.Andes Mountains: Mountain range on the west coast

of South America resulting from the collision of two continental plates.

Page 5: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

Transform Boundary: Plates sliding past each other. (San Andreas Fault)

Subduction/Subduction Zone: Type of convergent boundary; one plate slips under another plate.

Page 6: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.
Page 7: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

Plate boundaries can be found using page 5 of your ESRT . . .

[Seek and ye shall find!]

Page 8: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

The west coast of South America is a subduction zone.

The Nazca Plate (oceanic & more dense ~ 3.0g/cm3) is sliding under the South American plate (less dense ~ 2.7g/cm3).

Earthquakes occur at the boundary between the plates – the earthquakes get deeper as the plate slips farther under . . .

Cross Section of Subduction Boundary ( km below surface)

0 100 200 300 400 500

(South American Plate) Continental Crust Oceanic Crust 2.7 g/cm3 3.0 g/cm3

(Nazca Plate)

Page 9: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

Cross Section of Subduction Boundary ( km below surface)

0 100 200 300 400 500

(South American Plate) Continental Crust Oceanic Crust 2.7 g/cm3 3.0 g/cm3

(Nazca Plate)

A B* Depth of

Earthquakes

* = Shallow

= Intermediate

= Deep

As we move along the line

from A (west) to B (east), the depth of the earthquakes increases. as oceanic plate

subducts (goes below) under

continental plate.

Page 10: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

1. Earthquake depth increases moving east where the Nazca and South American plates converge.

2. Earthquake depth increases because the Nazca Plate is subducting under the South American Plate.

3. The Andes Mountains have formed on the west coast of South America as a result of a convergent collision boundary.

Page 11: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

4. Most divergent plate boundaries are found in the oceans.

5. The San Andreas Fault is a transform boundary.

6. A subduction zone is found at a convergent boundary.

7. New oceanic crust is created at a divergent boundary.

8. Oceanic trenches are associated with convergent/subduction boundaries.

Page 12: We know the Earth is broken into 8 major lithospheric plates …. We know these plates move …. We know there are boundaries between the plates …. Now, let’s.

Divergent boundaries form when two plates are moving away from each other and result in the formation of ridges.

Convergent boundaries occur when two plates are moving toward each other; can be subduction (forming a trench) or collision (forming mountain ranges).

Transform boundaries move horizontally past each other.