Theory of Plate Tectonics

Questions and Answers

What is the primary feature of divergent boundaries?

Plates collide with each other

Plates sink into the mantle

Plates slide past each other

Plates are moving apart (correct)

Plate tectonics is a theory that proposes Earth's lithosphere is unbroken and static.

False

What type of boundary forms when two tectonic plates slide horizontally past each other?

Rift Boundary

Convergent Boundary

Divergent Boundary

Transform Boundary (correct)

How many major tectonic plates have been identified by scientists?

7 Signup and view all the answers

The theory of plate tectonics describes pieces of Earth's lithosphere that are called _______ plates.

tectonic Signup and view all the answers

Subduction occurs when two plates of similar density collide.

False Signup and view all the answers

Match the following plate interactions with their corresponding description:

Divergent Boundaries = Where two tectonic plates move apart Convergent Boundaries = Where two tectonic plates collide Transform Boundaries = Where two tectonic plates slide past each other Plate Tectonics = Theory explaining the movement of lithospheric plates Signup and view all the answers

What geological feature is formed by divergent boundaries on land?

rift Signup and view all the answers

Earthquakes are a characteristic of ____ boundaries.

transform Signup and view all the answers

Match the following boundary types with their characteristics:

Divergent = Forms rift valleys Transform = Creates shallow earthquakes Convergent = Involves subduction Continental Crust = Less dense plate Signup and view all the answers

Study Notes

Theory of Plate Tectonics

Earth's lithosphere is divided into tectonic plates that can move and interact on the surface.
There are 7 major tectonic plates and many smaller ones on Earth.
Plates move in various directions and speeds relative to each other, interacting at boundaries.

Types of Boundaries

Divergent Boundaries

Formed when two tectonic plates separate, typically found on the seafloor.
Example: Mid-Atlantic Ridge.
Characteristics include volcanic mountains, earthquakes, and extreme heat.
Can lead to the creation of rift valleys, such as the Great Rift Valley in Africa, due to continental crust separation.

Transform Boundaries

Occur where two plates slide past each other horizontally.
Characterized by long faults, creating significant breaks in the Earth's landmass.
Associated with shallow earthquakes; notable example is the San Andreas Fault in California.

Convergent Boundaries

Form when two tectonic plates move towards each other, leading to subduction of the denser plate beneath the less dense plate.
Three types classified by the type of crust involved:
- Oceanic-Oceanic Convergent Boundary
  - One denser oceanic plate descends beneath another, creating an ocean trench and a row of parallel volcanoes.
- Oceanic-Continental Convergent Boundary
  - Denser oceanic plate is subducted under the less dense continental crust, forming a trench and volcanic mountain range (e.g., Mt. St. Helens in the Cascade Mountains).
- Continental-Continental Convergent Boundary
  - Occur when two continental plates collide, leading to complex mountain formations as one plate is pushed beneath the other.