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Mountain ranges appear all over the world. Take a look at this website that looks into mountain ranges in Asia.

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The Kunlun Mountains, in China, is the longest mountain range in Asia.

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Our world used to look a lot different. Read this article to see how plate tectonics has changed the way out earth looks.

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Table of Contents

How long ago did Pangea exist?

What is a supercontinent?

How did Pangea's formation affect life on Earth?

How did Pangea affect Earth's climate?

Pangea, also spelled Pangaea, in early geologic time, a supercontinent that incorporated almost all the landmasses on Earth. Pangea was surrounded by a global ocean called Panthalassa, and it was fully assembled by the Early Permian Epoch (some 299 million to about 273 million years ago). The supercontinent began to break apart about 200 million years ago, during the Early Jurassic Epoch (201 million to 174 million years ago), eventually forming the modern continents and the Atlantic and Indian oceans. Pangea's existence was first proposed in 1912 by German meteorologist Alfred Wegener as a part of his theory of continental drift. Its name is derived from the Greek pangaia, meaning "all the Earth."

Formation

The assembly of Pangea's component landmasses was well underway by the Devonian Period (419.2 million to 358.9 million years ago) as the paleocontinents Laurentia (a landmass made up of the North American craton-that is, the continent's stable interior portion) and Baltica (a landmass made up of the Eastern European craton) joined with several smaller microcontinents to form Euramerica. By the beginning of the Permian Period (298.9 million to 252.2 million years ago), the northwestern coastline of the ancient continent Gondwana (a paleocontinent that would eventually fragment to become South America, India, Africa, Australia, and Antarctica) collided with and joined the southern part of Euramerica (a paleocontinent made up of North America and southern Europe). With the fusion of the Angaran craton of Siberia to that combined landmass during the middle of the Early Permian, the assembly of Pangea was complete.

Geography

Pangea was C-shaped, with the bulk of its mass stretching between Earth's northern and southern polar regions. The curve of the eastern edge of the supercontinent contained an embayment called the Tethys Sea, or Tethys Ocean. The Paleo-Tethys Ocean took shape during Pangea's initial assembly phase. This ocean was slowly replaced by the Neo-Tethys Ocean after a strip of continental material known as the Cimmerian continent, or the Cimmerian superterrane, detached from northern Gondwana and rotated northward.

On the periphery of Pangea was Cathaysia, a smaller continent extending beyond the eastern edge of Angara and comprising the landmasses of both North and South China. Cathaysia lay within the western Panthalassic Ocean and at the eastern end of the Paleo-Tethys Ocean. Both oceans also contained scattered fragments of continental crust (microcontinents), basaltic volcanic island arcs, oceanic plateaus, and trenches. These island arcs and other isolated landmasses were later welded onto the margins of Pangea, forming accreted terranes (landmasses that collide with continents).

The assembly of the various large landmasses into the supercontinent led to the development of extensive dry climates in the supercontinent's tropics during Permian times. As low-latitude seaways closed, warm surface ocean currents were deflected into much higher latitudes (areas closer to the poles), and cool-water upwelling developed along Pangea's west coast. Extensive mountain-building events (or orogenies) occurred where the continents collided with one another, and the newly created high mountain ranges strongly influenced local and regional terrestrial climates. East-west atmospheric flow in the temperate and higher latitudes was disrupted by two high mountain chains-one in the tropics oriented east-west and one running north-south-that diverted warm marine air into higher latitudes.

These developments may have contributed to the series of extinction events that took place near the end of the Permian Period. Paleoecologists have posited that continental collisions eliminated several shallow-water marine basins-the primary habitat of most marine invertebrates-and Pangea's north-south orientation, which drastically changed ocean circulation patterns, altered regional climates. In addition, by the end of the Permian Period, land largely prevented cooler waters near the poles from entering the Paleo-Tethys and Neo-Tethys basins, which may have raised water temperatures in shallow areas above the tolerance limits of corals and other organisms ( see also Permian extinction).

Breakup

The mechanism for the breakup of Pangea is now explained in terms of plate tectonics rather than Wegener's outmoded concept of continental drift, which simply stated that Earth's continents were once joined together into the supercontinent Pangea that lasted for most of geologic time. Plate tectonics states that Earth's outer shell, or lithosphere, consists of large rigid plates that move apart at oceanic ridges, come together at subduction zones, or slip past one another along fault lines. The pattern of seafloor spreading indicates that Pangea did not break apart all at once but rather fragmented in distinct stages. Plate tectonics also postulates that the continents joined with one another and broke apart several times in Earth's geologic history.

The first oceans formed from the breakup, some 180 million years ago, were the central Atlantic Ocean between northwestern Africa and North America and the southwestern Indian Ocean between Africa and Antarctica. The South Atlantic Ocean opened about 140 million years ago as Africa separated from South America. About the same time, India separated from Antarctica and Australia, forming the central Indian Ocean. Finally, about 80 million years ago, North America separated from Europe, Australia began to rift away from Antarctica, and India broke away from Madagascar. India eventually collided with Eurasia approximately 50 million years ago, forming the Himalayas.

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Pangea | Definition, Map, History, & Facts

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Pangea, also spelled Pangaea, in early geologic time, a supercontinent that incorporated almost all the landmasses on Earth. Pangea was surrounded by a global ocean called Panthalassa, and it was fully assembled by the Early Permian Epoch (some 299 million to about 273 million years ago).

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This kid friendly video helps to teach students about plate tectonics.

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Did You Know: Mountains Can Form Underwater?!

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Did You Know: Mountains Can Form Underwater?!

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You may be confused by the title of this. Did you know that mountain ranges can form under the ocean as well? Read this article to find out how and why!

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A mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics.

This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.

The mid-ocean ridges of the world are connected and form a single global mid-oceanic ridge system that is part of every ocean, making the mid-oceanic ridge system the longest mountain range in the world, with a total length of about 60,000 km.

There are two processes, ridge-push and slab-pull, thought to be responsible for the spreading seen at mid-ocean ridges, and there is some uncertainty as to which is dominant.

Ridge-push occurs when the weight of the ridge pushes the rest of the tectonic plate away from the ridge, often towards a subduction zone.

At the subduction zone, "slab-pull" comes into effect.

This is simply the weight of the tectonic plate being subducted (pulled) below the overlying plate dragging the rest of the plate along behind it.

The other process proposed to contribute to the formation of new oceanic crust at mid-ocean ridges is the "mantle conveyor" (see image).

However, there have been some studies which have shown that the upper mantle (asthenosphere) is too plastic (flexible) to generate enough friction to pull the tectonic plate along.

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A mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.

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Article: Introduction To Plate Tectonics

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Article: Introduction To Plate Tectonics

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This National Geographic article is introduction to plate tectonics. Students can read this and put together how plate tectonics affect patterns between earthquakes, volcanoes and mountain ranges.

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Image

Photograph by Georg Gerster

Plate tectonics is a scientific theory that explains how major landforms are created as a result of Earth's subterranean movements. The theory, which solidified in the 1960s, transformed the earth sciences by explaining many phenomena, including mountain building events, volcanoes, and earthquakes.

In plate tectonics, Earth's outermost layer, or lithosphere-made up of the crust and upper mantle-is broken into large rocky plates. These plates lie on top of a partially molten layer of rock called the asthenosphere. Due to the convection of the asthenosphere and lithosphere, the plates move relative to each other at different rates, from two to 15 centimeters (one to six inches) per year. This interaction of tectonic plates is responsible for many different geological formations such as the Himalaya mountain range in Asia, the East African Rift, and the San Andreas Fault in California, United States.

The idea that continents moved over time had been proposed before the 20th century. However, a German scientist named Alfred Wegener changed the scientific debate. Wegener published two articles about a concept called continental drift in 1912. He suggested that 200 million years ago, a supercontinent he called Pangaea began to break into pieces, its parts moving away from one another. The continents we see today are fragments of that supercontinent. To support his theory, Wegener pointed to matching rock formations and similar fossils in Brazil and West Africa. In addition, South America and Africa looked like they could fit together like puzzle pieces.

Despite being dismissed at first, the theory gained steam in the 1950s and 1960s as new data began to support the idea of continental drift. Maps of the ocean floor showed a massive undersea mountain range that almost circled the entire Earth. An American geologist named Harry Hess proposed that these ridges were the result of molten rock rising from the asthenosphere. As it came to the surface, the rock cooled, making new crust and spreading the seafloor away from the ridge in a conveyer-belt motion. Millions of years later, the crust would disappear into ocean trenches at places called subduction zones and cycle back into Earth. Magnetic data from the ocean floor and the relatively young age of oceanic crust supported Hess's hypothesis of seafloor spreading.

There was one nagging question with the plate tectonics theory: Most volcanoes are found above subduction zones, but some form far away from these plate boundaries. How could this be explained? This question was finally answered in 1963 by a Canadian geologist, John Tuzo Wilson. He proposed that volcanic island chains, like the Hawaiian Islands, are created by fixed "hot spots" in the mantle. At those places, magma forces its way upward through the moving plate of the sea floor. As the plate moves over the hot spot, one volcanic island after another is formed. Wilson's explanation gave further support to plate tectonics. Today, the theory is almost universally accepted.

Director

Tyson Brown, National Geographic Society

Author

National Geographic Society

Production Managers

Gina Borgia, National Geographic Society

Jeanna Sullivan, National Geographic Society

Program Specialists

Sarah Appleton, National Geographic Society, National Geographic Society

Margot Willis, National Geographic Society

Last Updated

August 17, 2022

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The theory of plate tectonics revolutionized the earth sciences by explaining how the movement of geologic plates causes mountain building, volcanoes, and earthquakes.

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This article explains one type of plate boundaries. Read this article to see what type of activity happens around this plate boundary.

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At divergent plate margins, plates are moving apart and new lithosphere is being created.

In the oceans, this has produced the mid ocean ridge system, which can also be described as a global range of underwater mountains. Well known ocean ridges include the Mid Atlantic Ridge, the East Pacific Rise, the Juan de Fuca Ridge, and the Galapagos Rise.

Within continents, divergent margins produce rift valleys such as the Red Sea and East African Rifts; and the lesser known West Antarctic Rift.

Case studies:

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At divergent plate margins, plates are moving apart and new lithosphere is being created. In the oceans, this has produced the mid ocean ridge system, which can also be described as a global range of underwater mountains. Well known ocean ridges include the Mid Atlantic Ridge, the East Pacific Rise, the Juan de Fuca Ridge, and the Galapagos Rise.

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This article talks about "Aftershocks". This explains what can happen once the initial earthquake hits.

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"Foreshock" and "aftershock" are relative terms.

Foreshocks are earthquakes that precede larger earthquakes in the same location. An earthquake cannot be identified as a foreshock until after a larger earthquake in the same area occurs.

Aftershocks are smaller earthquakes that occur in the same general area during the days to years following a larger event or "mainshock." They occur within 1-2 fault lengths away and during the period of time before the background seismicity level has resumed. As a general rule, aftershocks represent minor readjustments along the portion of a fault that slipped at the time of the mainshock. The frequency of these aftershocks decreases with time. Historically, deep earthquakes (>30 km) are much less likely to be followed by aftershocks than shallow earthquakes. (modified from Univ. of Washington)

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Foreshocks, aftershocks - what's the difference?

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"Foreshock" and "aftershock" are relative terms. Foreshocks are earthquakes that precede larger earthquakes in the same location. An earthquake cannot be identified as a foreshock until after a larger earthquake in the same area occurs. Aftershocks are smaller earthquakes that occur in the same general area during the days to years following a larger event or "mainshock."

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This National Geographic video teaches what happens when volcanoes erupts.

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This short video explains how mountain ranges form around convergent plate boundaries.

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How mountain ranges are formed at convergent plate boundaries

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Read this short article that talks about why earthquakes form in certain areas.

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Locating earthquakes is essential for identifying fault structures and seismic hazards, modeling Earth's deeper structure, and monitoring nuclear detonations. Most methods rely on a one-dimensional velocity model to calculate arrival times of the seismic waves at many stations and a least-squares method to pinpoint the hypocenter by reducing the difference between the observed and calculated arrival times.

Using over 8 million arrival times recorded over the past 35 years, Nicholson et al. have developed a pattern recognition algorithm to locate earthquakes. An event's location is determined by how well its arrival time pattern fits with previous arrival time patterns. They tested this algorithm by relocating 395 nuclear blasts from the Nevada Test Site with greater accuracy than the least-squares method, placing more than 70% of the blasts within 1 km of ground truth depths. The pattern recognition algorithm offers an efficient alternative to the least-squares method because a velocity model is not needed, although small-scale heterogeneities can still be a source of error. - LR

J. Geophys. Res. 107, 10.1029/2000JB000035 (2002).

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GEOPHYSICS Locating earthquakes is essential for identifying fault structures and seismic hazards, modeling Earth's deeper structure, and monitoring nuclear detonations. Most methods rely on a one-dimensional velocity model to calculate arrival times of the seismic waves at many stations and a least-squares method to pinpoint the hypocenter by reducing the difference between the observed and calculated arrival times.

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This map depicts mountain ranges found in North America. Students can look at this to see if mountain ranges in North America form patterns.

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Landforms of North America, Mountain Ranges of North America, United States Landforms, Map of the Rocky Mountains - Worldatlas.com

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Look at this article to see pictures and statistics on current volcano eruptions.

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Is There a Correlation Between Earthquakes and Volcanoes?

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Is There a Correlation Between Earthquakes and Volcanoes?

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Take a look at this article. Do you believe that there is a correlation between where earthquakes and volcanoes happen?

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Tectonic Plates, Earthquakes, and Volcanoes | PBS LearningMedia

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According to the theory of plate tectonics, Earth is an active planet. Its surface is composed of many individual plates that move and interact, constantly changing and reshaping Earth's outer layer. Volcanoes and earthquakes both result from the movement of tectonic plates.

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National Geographic Video: Earthquakes 101

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National Geographic Video: Earthquakes 101

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This video helps explain what goes on during an earthquake.

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This government website gives statistics on different magnitude earthquakes that have happened all around the world!

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All Earthquakes
United States World
By Year
World
By Location

Use the Earthquake Catalog Search to find earthquakes within a certain distance of any location. Expand "Advanced Options" and fill in the "Circle" fields.
Search Earthquake Catalog *United States earthquake lists (except "Top...") also include some earthquakes outside the U.S. since the search area is a rectangle.
Statistics

Worldwide, United States, and average annual statistics for earthquake counts. U.S. and worldwide deaths per year. Earthquake counts by U.S. State.
Worldwide Earthquakes 2000-2019
Note: Estimated death counts for 2016-2019 are from EM-DAT: The Emergency Events Database - Université catholique de Louvain (UCL) - CRED, D. Guha-Sapir - www.emdat.be, Brussels, Belgium.
United States Earthquakes 2000-2012 Worldwide Earthquakes 1990-1999 United States Earthquakes 1990-1999 Earthquake Counts by State 2010-2015 (M3+)
Counts are as of March 10, 2016

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United States World World Use the Earthquake Catalog Search to find earthquakes within a certain distance of any location. Expand "Advanced Options" and fill in the "Circle" fields. Search Earthquake Catalog *United States earthquake lists (except "Top...") also include some earthquakes outside the U.S. since the search area is a rectangle.

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Look at this photo and discuss: Do volcanoes form around certain areas of the world?

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Detailed Description

Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire, a zone of frequent earthquakes and volcanic eruptions. The trenches are shown in blue-green. The volcanic island arcs, although not labelled, are parallel to, and always landward of, the trenches. For example, the island arc associated with the Aleutian Trench is represented by the long chain of volcanoes that make up the Aleutian Islands.

Details

Image Dimensions: 776 x 776

Credits

W. Jacquelyne and Robert I. Tilling

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Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire, a zone of frequent earthquakes and volcanic eruptions. The trenches are shown in blue-green. The volcanic island arcs, although not labelled, are parallel to, and always landward of, the trenches.

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This article outlines where mountain ranges form and how they form as well.

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This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they'd like an expert to answer. All questions are welcome - serious, weird or wacky! You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

How do mountains get made? - Astrid, age 6, Marrickville

Hello Astrid. You may not believe this but when I was about your age my teacher (Mr Rouve) explained to the class how mountains get made.

He took a sheet of paper and put it flat on the table. Then, he put the tips of his right and left hands' fingers on each side of the flat sheet and slowly moved his hands toward each other. Try to do it and you will see that the middle part of the paper will lift off the table to form a nice fold.

My teacher explained that mountains form in a similar way, when flat layers of rocks are pushed toward each other they move upward forming tall mountains.

My teacher was really excited by a discovery made by geologists at that time, when I was a kid. These geologists had figured out that the surface of the Earth was, like a giant jigsaw puzzle, made of pieces. Those pieces, called "tectonic plates", move and bump into each other.

This bumping creates earthquakes, which slowly push the ground surface upward to make mountains. It happens so slowly that, in fact, you are getting taller faster than mountains do, except mountains keep growing and growing and growing for many millions of years until they are so heavy they can no longer grow taller, only wider.

In fact, Australia and New Zealand are sitting on two different "tectonic plates" that move towards each other at the speed of a few centimetres per year. Where they bump into each other, the ground gets lifted to form the stunning New Zealand Alps, the top of which stands close to 4,000 metres. Can you imagine about 4,000 people as tall as you, standing straight up on each other shoulders? That's how tall these mountains are.

Shutterstock

Mountains also form when the Earth's crust is pushed upward from underneath. At the same time the New Zealand Alps started to form, a large hot bubble of rocks raising from deep in the Earth, like a giant air balloon, was pushing upward the surface of the eastern part of Africa forming a 4,000 metre high plateau. This plateau split to form what is known as the East African Rift, a valley twice as long as the New Zealands Alps.

There are many mountains at the surface of the Earth. Some we can see, some we can't because they are under the sea. If you could take a submarine and dive under the sea, for instance in the ocean in between Australia and Antarctica, you could visit a long mountain where the Australian and Antarctica tectonic plates move away from each other.

Thank you again for your fantastic question.

Read more: Curious Kids: What existed before the Big Bang? Did something have to be there to go boom?
Hello, curious kids! Have you got a question you'd like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au

CC BY-ND

Please tell us your name, age and which city you live in. We won't be able to answer every question but we will do our best.

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This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they'd like an expert to answer. All questions are welcome - serious, weird or wacky! You might also like the podcast Imagine This, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.

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This National Geographic article outlines specific earthquakes that have happened and the effects of them.

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You feel the ground suddenly shake, and nearby objects are trembling. An earthquake is happening.

Also called a temblor, an earthquake is caused by the movement of parts of the Earth's crust, its outermost layer. They happen millions of times a year, but most are so small people don't even feel them.

But powerful earthquakes can cause landslides, tsunamis, flooding, and other dangerous events. Most damage and deaths happen in places where a lot of people live, because the shaking causes windows to break, structures to collapse, fire to break out, and other dangers.

Learn more about these unpredictable Earth tremors-and what to do if one rattles near you.

How earthquakes develop

The action all starts thousands of miles below your feet.

Picture Earth as a hard-boiled egg: Earth's core is the yolk, and the mantle is the white part. The outer crust is the eggshell.

People live on the surface of the crust. Below the surface-but still within the crust-are tectonic plates. Like gigantic puzzle pieces, these huge slabs of rock encircle the Earth. The seven major plates are named for the regions they rest under: the African, Antarctic, Eurasian, Indo-Australian, North American, Pacific, and South American tectonic plates

Tectonic plates aren't connected but are close together. Where they meet along their edges is called a fault. When heat from the Earth's core creates currents in the crust, the tectonic plates can scrape, bump, or drag along each other. This is what causes an earthquake-and why the surface sometimes cracks like an eggshell.

How to measure earthquakes

About a half-million quakes rock the Earth every day. Usually the quake is too small, too far below the surface, or too deep in the seafloor to be felt. Some, however, are so powerful they can be felt thousands of miles away.

The spot on the surface just above where an earthquake starts is called the epicenter. Ripples called seismic waves travel out from the epicenter. This causes vibrations that people can feel, sometimes very far from the epicenter.

How far away people can feel an earthquake's vibrations depends on its size, or magnitude. Scientists base the magnitude on the strength and duration of the quake's seismic waves. The higher the number, the more powerful the earthquake: A magnitude 3 to 4.9 earthquake is considered minor; 5 to 6.9 is moderate to strong; 7 to 7.9 is major; and 8 or more is an extremely powerful temblor.

As the crust settles after an earthquake, another temblor called an aftershock can happen. Usually, aftershocks are not as powerful as the first quake but can still be very strong.

Geologists can't predict earthquakes. But they're working to change that with new research and technology.

Where earthquakes happen

Earthquakes occur along faults, the areas where tectonic plates meet. About 80 percent of earthquakes occur along the rim of the Pacific Ocean. Called the Ring of Fire because of the large number of volcanoes there, the area is a meeting point for many tectonic plates.

Earthquakes are also common in California because the region sits on top of the Pacific and North American tectonic plates. Temblors happen when these two plates grind against each other. About two-thirds of this movement happens along the San Andreas Fault.

Another major earthquake area in the United States is the New Madrid Seismic Zone, which affects Missouri, Arkansas, Tennessee, Kentucky, and Illinois.

How to survive an earthquake

Earthquakes can happen anytime or anywhere-even if you don't live near a fault. So it's a good idea to prepare.

* Talk with your family about the safest places in your home in case an earthquake hits. This could be under a sturdy table or next to an interior wall (one that is not connected to the outside).

* Look for heavy items that could fall or break during a quake, and move them to safer spots.

* Ask your parents to make sure you have an emergency kit containing things like first-aid supplies, a flashlight, a cell phone charger, and a battery-operated radio. Your family should also have enough food and water for at least 72 hours

DURING AN EARTHQUAKE: Most earthquakes last only 10 to 30 seconds, so it's important to get to a safe place fast. Remember three things during an earthquake: drop, cover, and hold on.

Drop: Get down on your hands and knees and crawl to your shelter.

Cover: Underneath a sturdy table, desk, or bed, cover your head and neck with your arms. If furniture isn't nearby, crouch down on your knees with your arms over your head and neck next to an interior wall. (Don't stand under a doorway-they can easily collapse.)

Hold on: If you're under a piece of furniture, hold on with one hand and move with the furniture if it starts sliding. Stay where you are until the shaking stops.

AFTER AN EARTHQUAKE: Once the earthquake ends, check for injuries. Listen to a radio for any warnings and instructions from official organizations like the United States Geological Survey. Be prepared for any aftershocks.

Text and images adapted from Everything Volcanoes and Earthquakes: Earthshaking photos, facts, and fun!

(Learn more about earthquakes at National Geographic.)

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Learn the science behind how earthquakes happen-and how you can stay safe if one hits.

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Image: Where do earthquakes usually happen?

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Image: Where do earthquakes usually happen?

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Students could reference this photo to see the patterns of where earthquakes usually occur at. This helps answer the question if there are patterns between locations of earthquakes.

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Where do earthquakes happen? Part of the Exploring the Earth Using Seismology poster. Earth's outer surface, the Earth's crust, is broken into what geologists call tectonic plates. These plates move under, over, or slide past each other. The plates are driven by hot mantle materials that convect. The relative motion of plates is associated with earthquakes. Most earthquakes occur along the edges of large plates. The arrows on the map above indicate how fast the plates are moving in millimeters per year.

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Where do earthquakes happen? Part of the Exploring the Earth Using Seismology poster. Earth's outer surface, the Earth's crust, is broken into what geologists call tectonic plates. These plates move under, over, or slide past each other. The plates are driven by hot mantle materials that convect.

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This is a short introductory video about volcanoes. I would use this to help show students the basics of what volcanoes are and what they are made of.