Lesson 5:Part 1 Flashcards
(16 cards)
This theory says Earth’s outer shell is made of separate plates that move and interact.
Theory of Plate Tectonics
7 Major Plates
- Pacific Plate
- North American Plate
- Eurasian Plate
- African Plate
- Antarctic Plate
- Indo-Australian Plate
- South American Plate
Plates move slowly at about 5 cm or 2
inches per year.
Plate Movement
This movement is caused by uneven heat inside the Earth:
Core: 5200–6700 °C
Mantle: 1000–3700 °C
Why do plates move?
Because of heat differences in the Earth’s interior.
As plates move, boundaries form.
Scientists first found these boundaries by mapping
earthquake locations.
Plate Boundaries
Types of Plate Boundaries:
- Divergent
- Convergent
- Transform Fault
Plates pull apart. Also called spreading centers
Divergent Boundary
A chain of mountains under the sea. formed at divergent boundaries.
Oceanic Ridge
The mechanism that operates along the oceanic ridge system to create new seafloor.
Seafloor Spreading
The splitting of a continent is thought to begin with
the formation of an elongated depression called
Continental Rifting
It occurs when two plates move toward each other
and the denser plate slides below the less dense
plate. Also called subduction zones because these are sites where lithosphere is descending (being
subducted) into the mantle.
Convergent Boundary
An oceanic plate collides with a continental plate. The oceanic plate subducts in the mantle.
Oceanic-Continental Convergence
Two oceanic plates
collide and the denser plate subducts into the mantle
Oceanic-Oceanic Convergence
Two land plates (buoyant) collide resulting to mountain ranges
Continental-Continental Convergence
Two plates slide horizontally past each other without production or destruction of lithosphere
Transform Fault Boundary
