You along the eastern U.S. seaboard between the

You can’t spell ‘plateau’ without ‘plate,’ and there is a good reason for that – both of these objects are, by definition, flat. This lesson will further explain the definition of plateau and discuss some different types of these flat landforms.

Defining Plateau

A plateau is a flat area of land that is elevated above sea level. The word is French for ‘table land,’ and that term is also used for some smaller landforms that will be discussed further into this lesson.

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Plateaus aren’t all perfectly flat, but they do have low relief; relief means the elevation change across an area.Given the rather straightforward definition, you may be surprised to learn that there are a lot of different kinds of plateaus. Plateaus are classified based on how they form and where they are found.

Most plateaus are found in areas of tectonic uplift, which is often, but not always, associated with mountain ranges. But, they can form in other ways, as well.

Intermontane Plateaus

Many plateaus are located in or near mountain ranges, where tectonic uplift raised broad areas of flat land as a single unit. As a group, they are called intermontane plateaus. Let’s look at these more closely.The largest plateaus on Earth formed where two tectonic plates collided. Because they are lifted far above sea level, they are known as high altitude plateaus.

The largest and highest is the Tibetan Plateau in South-Central Asia, which is a flat valley floor at about 15,000 feet above sea level, rimmed on the south by the Himalayas.The Altiplano, which literally means ‘high plain,’ is located in the Andes in western South America. It is the second largest high altitude plateau in the world, and it lies at an elevation above 12,000 feet.

Other Types of Plateaus

The term continental plateau is applied to a broad plateau that was not lifted by plate collisions. Geologists appear to have a lot of possible explanations for how they form, most involving upward movement of rocks in the upper mantle or lower lithosphere. But, there does not seem to be a consensus.

One characteristic of these landforms is that the rate of uplift is usually slow, which allows streams flowing across them to carve deep canyons into the plateau surface. The Colorado Plateau, which includes the Grand Canyon, is one example. The Ozark Plateau in Missouri and Arkansas is another.The area located between a mountain range and an adjacent coastal plain is called the piedmont, and it lends its name to this type of plateau.

Think of this plateau as a stair-step to a mountain range. A good example is the area along the eastern U.S. seaboard between the Appalachian Mountains and the Atlantic coastal plain. The elevation change between the piedmont and coastal plain isn’t as dramatic as that of other plateaus, but it is enough to create a string of waterfalls, called the fall line, where streams flowing across the piedmont drop onto the coastal plain.Volcanic plateaus consist of thousands of feet of lava flows that were deposited by massive eruptions of basalt lava millions of years ago.

Because of their composition, they are sometimes called basalt plateaus. The Columbia Plateau in Oregon and Washington, the Parana Plateau in Argentina, the Central Siberian Plateau in Russia, and the Deccan Plateau in India are all volcanic plateaus.Almost all plateaus are eroded to some extent, especially along their edges. Geologists refer to that situation as dissection. After erosion has carved into a plateau over a long period of time, the plateau might be called a dissected plateau. The eastern edge of the Tibetan Plateau is dissected by streams and tributaries to rivers, such as the Yangtze and Irrawaddy Rivers, and most of the plateau is intact.

The Colorado and Ozark plateaus are also dissected by stream erosion.Last (and perhaps least) we come to tablelands, which are small, flat-topped landforms found in desert regions. They are remnants of larger plateaus that have been eroded on all sides. The mesas in the Southwest United States are examples. Tablelands are not found in wetter climates because the tops are rounded off by weathering and erosion.

Lesson Summary

Let’s review:

  • A plateau is a flat area of land that is elevated above sea level. Not all plateaus are perfectly flat, but they do have low relief; relief means the elevation change across an area. Almost all plateaus are eroded to some extent, especially along their edges. Geologists refer to that situation as dissection.

  • Many plateaus are located in or near mountain ranges where tectonic uplift raised broad areas of flat land as a single unit. As a group, they are called intermontane plateaus; they include high altitude plateaus, which are lifted by tectonic plate collisions. The largest and highest is the Tibetan Plateau in South-Central Asia.

Now let’s review the other types of plateaus:

  • Continental plateaus typically involve upward movement of rocks in the upper mantle or lower lithosphere.
  • Piedmont plateaus are plateaus that are trapped between mountains and a coastal plain.

    The elevation change between the piedmont and coastal plain can create a string of waterfalls, called the fall line, where streams flow across the piedmont drop onto the coastal plain.

  • Volcanic plateaus consist of thousands of feet of lava flows that were deposited by massive eruptions of basalt lava millions of years ago, and, because of their composition, are sometimes called basalt plateaus.
  • Dissected plateaus have been carved by erosion over a long period of time.
  • Tablelands are small, flat-topped landforms found in desert regions; they are remnants of larger plateaus that have been eroded on all sides. The mesas in the Southwest United States are examples of tablelands.

Types of Plateaus

Plateau definition
  • Intermontane Plateaus: located in or near mountain ranges
  • High Altitude Plateaus: formed when two tectonic plates collide
  • Continental Plateaus: broad plateau not lifted by plate collisions
  • Piedmont Plateaus:located between a mountain range and an adjacent coastal plain
  • Volcanic Plateaus: made of thousands of feet of lava flows deposited by massive eruptions of basalt lava
  • Dissected Plateaus: carved by erosion
  • Tablelands:small flat-topped remnants of larger plateaus that have been eroded on all sides

Learning Outcomes

Once you are finished, you should be able to:

  • State what a plateau is and discuss the different ways it can be formed
  • Name and describe the different types of plateaus
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