Science 10 Lesson 2 Plate Boundaries.ppt

Science 10 Plate Boundaries

1. PLATE
BOUNDARIES

2. Figure 1. Map of Plate Boundaries

3. Plate boundaries - lines at the edges of the
different pieces of the lithosphere.
Lithospheric plates are moving due to the
convection current in the Earth’s interior.
Plate Tectonic Theory - Earth’s lithosphere consists
of the crust and upper mantle that move slowly and
constantly over time. This movement causes the
formation of plate boundaries namely: divergent,
convergent, and transform fault boundaries.

5. Types of Plate Boundaries
A. Convergent (collisional) boundaries
- where plates meet.
- driven by compressional forces.
- can create two possible landforms: trenches
or mountains/volcanoes
- where most of the destruction of crust takes
place (subduction zone)

6. Andes Mountains,
South America

7. Mariana Trench
2,550 kilometres (1,580
 mi) long but has a mean width of
only 69 kilometres, dbbepth of about 10.91 kilometres

9. Types of Convergent
Boundaries
1.An ocean floor plate collides with a less
dense continental plate.

10. Types of Convergent
Boundaries
2. An ocean floor plate collides with another
ocean floor plate.

11. Types of Convergent
Boundaries
3. A continental plate collides with another
continental plate.

12. from: http://www.geo.lsa.umich.edu/~crlb/COURSES/270
Before collision
After collision

13. Types of Boundaries
B. Divergent boundaries
- where plates move away from each
other.
- driven by tensional forces.
- either occurs at mid-ocean ridges
(seafloor spreading) or at rifted continental
margins (rift valley).

15. Seafloor Spreading
developed by geologists Harold Hess (1895-1982) and Robert
Dietz (1914-1995).
a continuous process where tensional forces on both sides of the
plates cause them to constantly move apart.
the process that continually adds new material to the ocean floor
while pushing older rocks away from the ridge.
the center of it is the youngest and newest portion of Earth’s crust.
.

18. Where can you find the
longest mountain range?
Seafloor spreading happen along mid-oceanic ridges (longest chain
of mountains)

20. Types of Boundaries
C. Transform boundaries
- where plates slide past each other.
- sdden movement can cause
earthquakes.
- neither plate gets subdued.

22. Types of Boundaries
C. Transform-fault boundaries
- strike-slip fault
- transform fault usually happen in the
fracture zone that connect to deep-sea trenches
Ex. transform faults near Taiwan and the
Philippine Trench.

25. Quick Review of Plate BoundariesQuick Review of Plate Boundaries

26. Find the Boundary
on the Map!

27. Identify the plates that lie on the divergent, convergent,
and transform fault boundaries.