Plate Tectonics Theory Lesson

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.

​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.

​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!

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.

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

​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.

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

• Divergent boundaries occur in the ocean and on land

• Seafloor spreading forms new land

• Mid-Atlantic Ridge mountains

• Part of Africa is splitting off

Plate Boundaries: 3 types!

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

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