Plateaus in the ocean are divided into two groups. One group is made of continental crust. The other is made of igneous rock. Igneous oceanic plateaus represent an age between the older, less-dense continental crust and the younger, more dense oceanic crust.
A plateau is a flat, elevated landform that rises sharply above the surrounding area on at least one side. Plateaus occur on every continent and take up a third of the Earths land. They are one of the four major landforms, along with mountains, plains, and hills.
There are two kinds of plateaus: dissected plateaus and volcanic plateaus. A dissected plateau forms as a result of upward movement in the Earths crust. The uplift is caused by the slow collision of tectonic plates. The Colorado Plateau, in the western United States, has been rising about .03 centimeter (.01 inch) a year for more than 10 million years.
A volcanic plateau is formed by numerous small volcanic eruptions that slowly build up over time, forming a plateau from the resulting lava flows. The North Island Volcanic Plateau covers most of the central part of the North Island of New Zealand. This volcanic plateau still has three active volcanoes: Mount Tongariro, Mount Ngauruhoe, and Mount Ruapehu.
Erosion can influence the shape of a plateau. Soft rock often erodes away on the top of a plateau. Many plateaus are therefore topped with a hard, durable surface called caprock. Caprock protects the plateau from erosion of the soil underneath it.
Valleys form when river water cuts through the plateau. The Columbia Plateau, between the Cascade and Rocky mountains in the northwestern United States, is cut through by the Columbia River.
Erosion shapes plateaus in other ways. Sometimes, a plateau is so eroded that it is broken up into smaller raised sections called outliers. Many outlier plateaus are composed of very old, dense rock formations. Iron ore and coal often are found in plateau outliers.
The largest plateau in the world is the Tibetan Plateau, located in central Asia. It stretches through the countries of Tibet, China, and India and occupies an area of 2.5 million square kilometers (1.5 million square miles), which is four times the size of the U.S. state of Texas.
Term Part of Speech Definition Encyclopedic Entry active volcano Noun
volcano that has had a recorded eruption since the last glacial period, about 10,000 years ago.
strong, hard rock that remains on top of a mesa.
dark, solid fossil fuel mined from the earth.
one of the seven main land masses on Earth.
Encyclopedic Entry: continent continental crust Noun
thick layer of Earth that sits beneath continents.
having parts or molecules that are packed closely together.
dissected plateau Noun
flat, elevated landform created by upward movement of the Earth's crust.
strong and long-lasting.
act in which earth is worn away, often by water, wind, or ice.
Encyclopedic Entry: erosion igneous rock Noun
rock formed by the cooling of magma or lava.
chemical element with the symbol Fe.
specific natural feature on the Earth's surface.
Encyclopedic Entry: landform oceanic crust Noun
thin layer of the Earth that sits beneath ocean basins.
oceanic plateau Noun
flat, elevated landform rising from the ocean floor.
deposit in the Earth of minerals containing valuable metal.
Encyclopedic Entry: ore outlier Noun
part of a landform separated from the rest by erosion.
large region that is higher than the surrounding area and relatively flat.
Encyclopedic Entry: plateau river Noun
large stream of flowing fresh water.
Encyclopedic Entry: river soft rock Noun
solid mineral matter that is easily worn or broken.
tectonic plate Noun
large, moveable segment of the Earth's crust.
Tibetan Plateau Noun
flat, elevated landform located in Tibet, China, and India. Also known as the "rooftop of the world."
depression in the Earth between hills.
volcanic plateau Noun
flat, elevated landform created by layers of lava from volcanic eruptions.