Plate Tectonics Theory Lesson

Plate Tectonics Theory

Discovering the hidden forces shaping our planet's surface through the study of plate tectonics.

Alfred Wegener

Proposed the theory of plate tectonics in 1912, as well as the idea of a supercontinent he called Pangea,
which he claimed broke up
over 200 million years ago.

​Alfred Wegener proposed "Pangea"

​Puzzle Pieces

Alfred Wegener pointed out that the continents resembled puzzle pieces that may have once fit together - but they didn't like that idea and called him crazy.

Plate Tectonics Theory

Alfred Wegener proposed the theory of plate tectonics and named the supercontinent Pangea.

This theory explains how Earth's lithosphere is divided into several large and small plates that constantly move and interact, causing earthquakes, volcanic activity, and the formation of mountains!

​Earth's Tectonic Plates

​Earth has 7 major tectonic plates, with 8 minor plates in between.

Multiple Choice

Who proposed the theory of plate tectonics and named the supercontinent Pangea?

• Alfred Wegener

• Charles Darwin

• Isaac Newton

• Marie Curie

Multiple Choice

How long ago did Pangea break up?

• 50 million years ago

• 100 million years ago

• 200 million years ago

• 200 billion years ago

​Evidence for Wegener!

After his death, scientists began finding evidence to support Wegener's ideas!

New discoveries of fossil evidence, seafloor spreading at divergent oceanic plate boundaries, and locations of volcanic eruptions along plate boundaries all supported his theories!

​Seafloor Spreading

​Volcanoes on Plate Boundaries

​Volcanoes on Plate Boundaries

​Tropical fossils found in non-tropical places

​Tropical fossils found in non-tropical places

​Glacial Striations found across continents

Multiple Select

Which provided evidence for Alfred Wegener's theory?

• Proof of seafloor spreading on the ocean floor

• Fossils from tropical species found in non-tropical places

• The locations of volcanoes on proposed plate boundaries

• Scratch marks left from glaciers moving across continents

Plate Tectonics Theory

The Earth's outer mechanical layer, the lithosphere, is divided into large continent-sized plates that are constantly moving. These are also called "lithospheric plates"


This theory explains how the
movement of these plates
leads to various geological
phenomena such as
earthquakes, volcanic activity,
and mountain formation.

Multiple Choice

What geological phenomena are caused by the movement of the Earth's lithospheric plates?

• Tsunamis, hurricanes, and tornadoes

• Erosion, weathering, and deposition

• Fossilization, sedimentation, and erosion

• Earthquakes, volcanic activity, and the formation of mountains

Plate Tectonics

Trivia: The movement of Earth's lithospheric plates causes earthquakes, volcanic activity, and the formation of mountain ranges.

This process, known as plate tectonics, is responsible for shaping the Earth's surface over millions of years.

It is a key concept in geology and helps explain the distribution of continents and the occurrence of natural disasters.

Transform Boundaries

• Transform boundaries are when plates are moving in opposite directions and grinding past one another.

• Sometimes they get stuck and cause earthquakes.

• Famous fault line:
  San Andreas Fault

​San Andreas Fault

​The San Andreas Fault is a major fault line located along the western coast of California. It is responsible for all of their earthquakes!!!

Subduction Zones

Trivia: Convergent boundaries cause subduction zones. These are areas where one tectonic plate is forced beneath another.

The process leads to the formation of deep ocean trenches, volcanic arcs, and earthquakes.

Subduction zones are crucial for the recycling of Earth's crust and the creation of mountain ranges.

​Subduction Zone

​often occurs where oceanic and continental crust collide -
oceanic crust is heavier, so it subducts.

Divergent Boundaries

• Divergent boundaries occur in the ocean and on land

• Seafloor spreading forms new land

• Mid-Atlantic Ridge mountains

• Part of Africa is splitting off

Multiple Choice

Which type of plate boundary causes subduction zones?

• Convergent boundaries

• Divergent boundaries

• Transform boundaries

• None of the above

Plate Boundaries: 3 types!

Convergent: Plates collide and create mountains
---> <----

Divergent: Plates separate and create new crust
<--- --->
Transform: Plates slide past each other, causing earthquakes

---->
<----

​3 Types of Plate Boundaries

Multiple Choice

What are the three types of plate boundaries?

• Convergent, Divergent, Transform

• Collision, Separation, Sliding

• Earthquakes, Mountains, Fissures

• Seafloor spreading, Rifts, Fault lines