ARTICLE

ARTICLE

Dome

Dome

A dome is a curved formation or structure. It is shaped like half of a sphere.

Grades

4 - 12+

Subjects

Earth Science, Geology, Geography, Physical Geography, Arts and Music, Mathematics

















NGS Resource Carousel Loading Logo
Loading ...
Powered by
Morgan Stanley

A dome is a curved formation or structure. It is shaped like half of a sphere. Imagine cutting an orange in half, and placing it cut-side-down on a table. This is the shape of a dome, although most domes in nature are not perfectly rounded.

Some natural domes develop when magma from deep within the Earth pushes up surface rock layers. This type of geologic dome can form as magma intrudes between two layers of sedimentary rock. The magma creates a dome or triangle shape as it pushes the other layers apart. The hardened magma that forms this type of dome is called laccolith.

Lava domes form as lava hardens atop volcanic vents. In the Chaitn Volcano in Chile, an ongoing eruption that began in 2008 is forming a lava dome next to another one that completely filled the crater when the volcano erupted 9,400 years ago.

Another kind of dome is shaped primarily by weathering and erosion, which cause curved sheets of rock to separate from a large rock mass. The Cima Dome in the Mojave Desert, in the U.S. state of California, was once a mountain. Over time, weathering and erosion wore away the mountain and smoothed it into a rounded dome.

Salt Domes

Salt domes result when rock salt rises through overlying sedimentary rock. Salt accumulates as ancient seas dry up over time. Eventually, sediments form over this layer of salt. Salt is less dense than most other rocks, and it slowly moves upward toward the surface, forming a dome-shaped hill.

One of the most famous salt domes is Avery Island, in the U.S. state of Louisiana. Avery Island is a salt dome surrounded by low-lying swamps of the Mississippi River delta.

Eventually, these salt domes can break through the surface rock layers. Sometimes, the salt beneath a salt dome is enough to create a salt glacier. Salt glaciers behave like ice glaciers, moving slowly down a mountainside. Salt glaciers are most active in the winter, when they are filled with moisture from snow and rain. The Zagros Mountains in Iraq and Iran have formed over a series of salt domes, and have active salt glaciers.


Salt domes are important sites for industry. Salt is a valuable mineral used in the production of plastics, pesticides, preservatives, and fire extinguishing equipment. The salt mines near Avery Island and in the Zagros Mountains are hundreds of years old.

Salt domes are also important for the petroleum industry. Salt domes trap oil between layers of rock. Oil wells can drill into the salt dome and extract oil. Salt domes on the coast and beneath the Gulf of Mexico often reveal oil deposits.

Architectural Domes

Domes are one of the most familiar features in architecture, or the structure of buildings. One of the most famous domes is the Taj Mahal, a mausoleum in Agra, India.

Domes are frequently used for government buildings, such as the U.S. Capitol in Washington, D.C. They are also used in religious architecture, such as the Dome of the Rock, an Islamic shrine in Jerusalem, Israel; and the Florence Cathedral, a Catholic church in Florence, Italy. (The Florence Cathedral is even nicknamed the Duomo or Brunelleschis Dome, after its architect, Filippo Brunelleschi.)

Russian architecture features domes shaped like onions. The most famous of these onion domes are probably those of St. Basil's Cathedral in Moscow.

Geodesic domes are created using a complex series of triangles. Geodesic domes are an efficient architectural design; they are stronger, lighter, and quicker to construct than more traditional buildings. They also enclose a large amount of space with minimal materials, labor, and energy.

Although geodesic domes enclose a lot of space, the shape and space are not easily used by people. Most furniture and machinery is made for flat walls. Although some geodesic houses have been built, most geodesic domes are used for public aviaries or sports facilities.

Fast Fact

Buckyballs
The geodesic dome was patented by American mathematician, inventor, and architect Buckminster Fuller. Years later, an unusual, 60-atom formation of the element carbon was discovered. It resembled the shape of a geodesic dome. The discoverers of this molecule named their discovery the buckminsterfullerene, nicknamed the buckyball.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Writers
Kim Rutledge
Melissa McDaniel
Santani Teng
Hilary Hall
Tara Ramroop
Erin Sprout
Jeff Hunt
Diane Boudreau
Hilary Costa
Illustrators
Mary Crooks, National Geographic Society
Tim Gunther
Editors
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
Educator Reviewer
Nancy Wynne
Producer
National Geographic Society
other
Last Updated

October 19, 2023

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

Media

If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

Text

Text on this page is printable and can be used according to our Terms of Service.

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

Related Resources