Plate Tectonics

Today we will explore the history of plate tectonics, different types of tectonic plates and some amazing facts about the plate. Let's begin.

plate_tectonics
The Earth - Then (supercontinent called Pangea) and Now (7 continents)

Before understanding Plate Tectonics, we will know about Hundreds of millions of years old facts related to the Earth.

Do you know that our Earth looked completely different from today’s Earth hundreds of millions of years ago?

As we all know that we have SEVEN continents, but at that time, all the continents of Earth were stuck together in a huge supercontinent called PANGEA.

In simple words, you can say that billions of years ago, there was only one continent called Pangea. The “Pangea” word is a Greek word meaning “all the earth.

A German meteorologist named Alfred Wegener theorized for the first time that this gigantic landmass split into chunks and slowly drifted apart. He created the idea of continental drift and wrote ‘The Origin of Continents and Oceans’ to support his theory.

Although the scientific community first rejected his theory, his ideas have been scientifically proven: The Earth’s crust is split up into dozens of pieces called tectonic plates, which float on top of the mantle.

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Tectonic Plates (pic:wikimedia)

What is Plate Tectonics?

The term ‘tectonics’ is a Greek word meaning ‘to build.’ Tectonic plates are huge pieces of land that connect to form the outer layer of the Earth.

There are mainly two types of tectonic plates: Continental Crust and Oceanic Crust

Continental Crust: The Earth’s outer rocky layer, made up of rocks that consist primarily of silica and aluminum called the “SIAL“

Oceanic Crust: Located below the continental crust, composed of an oceanic crust called “SIMA” Sima is made mostly of silicon and magnesium.

What are PlateTectonics made of?

Plate Tectonics are composed of both continental and oceanic lithosphere. The lithosphere is made up of the crust and the upper part of the mantle. These plates have irregular shapes and fit together, just like puzzle pieces.

Related ArticleLayers of the Earth

How do plates move?

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https://pubs.usgs.gov/gip/dynamic/unanswered.html
plate_tectonics
https://pubs.usgs.gov/gip/dynamic/unanswered.html

It is based on Convection Current theory. Convection currents transfer heat from one place to another by mass motion of a fluid or gas particles.

  • First less dense magma rises up due to heat,
  • Then cools, and eventually sinks back down.
  • As the cooled material sinks down, it reheats and rises again and forms a circular pattern of movement. This process happens continuously.
    Hot Material – goes UP
    Cool Material – goes DOWN

How many Tectonic Plates are there?

In all, the earth is divided into 12 plates.

SEVEN primary tectonic plates (also referred as major plates):

  • African plate
  • Antarctic plate
  • Indo-Australian plate
  • North American plate
  • Pacific plate
  • South American plate
  • Eurasian plate

Some of the secondary plates (also referred as minor plates):

  • Arabian plate
  • Caribbean plate
  • Nazca plate, and
  • Scotia plates

What is the Plate Tectonics Boundary?

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This picture shows the three main types of plate boundaries: divergent, convergent, and transform. Image Source: U.S. Geological Survey.

A tectonic plate boundary is the edges where two plates meet. These plates move slowly and continuously but in many different directions.

Based on the different movements, there are THREE main types of Tectonic plate boundaries:

  1. Divergent plate boundaries: two plates move apart from each other. Examples of Divergent plate boundaries are the Mid-Atlantic Ridge and the East Pacific Rise, East African rift.
  2. Convergent plate boundaries: two plates move towards each other. Examples of convergent plate boundaries are the Washington-Oregon coastline of the United States and the Andes Mountain Range of western South America.
  3. Transform plate boundaries: two plates slide past each other. An example of a convergent plate boundary is the San Andreas Fault in California, where the Pacific and the North-American plates move along.
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Most geologic activities, including volcanoes, earthquakes, and mountain building, take place at plate boundaries.

What is the Ring of Fire?

The Ring of Fire is a significant area in the basin of the Pacific Ocean. There are a string of earthquakes and volcanoes at the Pacific Plate’s edges that this region is called the Ring of Fire.

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Ring of Fire [pic source:Wikipedia]

In Summary - Plate Tectonics

Tectonic Plates

  • Billions of years ago, there was only one continent called Pangea.
  • The Earth’s crust is split up into dozens of pieces called Tectonic Plates, which float on top of the mantle.
  • Tectonic plates are made up of the crust and the upper part of the mantle called LITHOSPHERE.
  • 7 primary tectonic plates (also referred as major plates):
    1. African plate,
    2. Antarctic plate,
    3. Indo-Australian plate,
    4. North American plate,
    5. Pacific plate,
    6. South American plate,
    7. Eurasian plate

Tectonic Plate Boundaries

  • It is the edge where two plates meet.
  • Divergent – Pushed Apart
  • Convergent – Push Together
  • Transform – Slide Past

Types of Tectonic Plates

  1. Continental Crust: composed of silica and aluminum. Also referred as “SIAL“.
  2. Oceanic Crust: Located below the continental crust, composed of silicon and magnesium. Also referred as  “SIMA“.

Related ArticleLayers of the Atmosphere

Amazing Facts About Plate Tectonics

FACT 1. ➤ The Pacific Plate is the largest tectonic plate on the Earth’s Crust.

FACT 2. ➤ Juan de Fuca Plate is the smallest of Earth’s tectonic plates

FACT 3. ➤ There are mainly TWO types of tectonic plates: Continental and Oceanic crust.

FACT 4. ➤ Continental Crust is referred to as SIAL as it is composed of silica and aluminium.

FACT 5. ➤ Oceanic Crust is referred to as SIMA as it is composed of silicon and magnesium.

FACT 6. ➤ Earth tectonic plates float and move on top of the layer of the mantle known as Asthenosphere.

FACT 7. ➤ The Mariana Trench is the deepest part of the ocean. It is formed by a convergent boundary between the Pacific Plate and the Mariana Plate.

FACT 8. ➤ Plates move less than a few inches every year (about the same as your toenails grow.)

FACT 9. ➤ As tectonic plates press against each other, the pressure form Oil deposits, Natural gases, Coal and Metals.

FACT 10. ➤ The Himalayan mountains range including Mount Everest were formed because of the collision of Indian and Eurasian tectonic plates.

FACT 11. ➤ Using GPS, scientists are now able to track the movement of tectonic plates.

Plate Tectonics Frequently Asked Questions - FAQs

What are the 7 tectonic plates?

There are seven major plates: African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American.

What is the smallest tectonic plate?

Juan de Fuca Plate is the smallest tectonic plate.

Who first proposed the idea of plate tectonics?

A German meteorologist named Alfred Wegener theorized for the first time that this gigantic landmass split into chunks and slowly drifted apart. He created the idea of continental drift and wrote 'The Origin of Continents and Oceans' to support his theory.

How big is a tectonic plate?

The plates are around 100 km (62 mi) thick.

what tectonic plate is california on?

North American Plate

What type of plate boundary formed Mount Fuji?

Mt. Fuji is a product of the subduction zone

What are Tectonic Plates?

The tectonic plates are a combination of the crust and the uppermost part of the mantle, also called the lithosphere.

What type of plate boundary causes volcanoes?

Divergent Plate Boundaries

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