1. The continental rifting processq Kk

2. Continental
Crust
Rifting
Spreading
Center
Trench
Subduction
Basalt
Volcanic
Arc
Granite
Accretionary
Prism
Oceanic
Crust

3. Partial melting occurs when some minerals melt
while others remain solid because their melting point has not been reached
Granite
The role of
partial melting
Basalt

4. 3 Types of Plate Boundaries
DIVERGENT
New lithosphere forms as plates pull apart.
TRANSFORM
Plates grind past each other.
No change in Lithosphere
CONVERGENT
One plate dives beneath another (subduction) or two plates collide without either subducting.

5. Main Types of Plate Motion
Convergent
Divergent
Transform
Main Types of Plate Motion

6. MODERN CONTINENTS EVOLVED FROM PANGAEA
Linked on this slide is the animation:
Continents Form over Time

8. Divergent Boundary
Seafloor spreading leads to the formation of new crust that, compared to continental crust, is relatively enriched in iron and magnesium and depleted in silica (SiO2) (because it reflects the
chemistry of the mantle).
As two plates continue to move apart, the rock in the seafloor grows older as its distance from the rift zone increases, and as it ages, it cools and becomes denser and is buried under marine sediments that are deposited on the seafloor.

9. Mid-Ocean Ridge
Spreading Center

10. Transform boundary (side-to-side plate movement)
Suggested tips to give students:
Lots more about FAULTS coming up later in the course!
Fault
“a place where the crust is broken and the broken edges
are offset relative to each other
(either vertically or horizontally)”

11. Transform Boundaries Connect Two Spreading Centers
Occur where two plates slide past each other.
Motion called shearing.
Connect two spreading centers (less commonly, two subduction zones).
Probably the most famous transform boundary in the world is the San Andreas Fault.
Suggested tips to give students:
A Hotspot is a volcanic center located within a lithospheric plate that is thought to be caused by a plume of hot mantle material rising from depth. The Hawaiian Islands are created by a hotspot. J. Tuzon Wilson proposed both the Hotspot Hypothesis and that Transform Boundaries connect two spreading centers.

12. oceanic fracture zone Transform Boundary with inactive (fracture zone)
and active (transform fault) portions.