How Landforms Are Created

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How Landforms Are Created
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Primary Landforms

• Plate Tectonics The earths surface is
  broken up into large plates that are constantly
  moving and bumping into one another. Landforms
  created by tectonic activity are called primary
  landforms.

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• Tectonic plates are huge slabs of rock that
  float on liquid rock just below the earths
  crust. They move but often in different
  directions. Continents and oceans sit on these
  huge plates.

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• About 225 million years ago, all of the
  Earths landmasses were joined into one landmass
  called Pangaea. As time went on, the continents
  separated and moved to their current locations.

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• Divergent plate boundaries are areas where two
  plates move away from each other. As they move
  apart, new crust is formed by magma that is
  pushed up.

Mid-Atlantic Ridge
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• Convergent and Transform plate boundaries
  occur when tectonic plates push against each
  other.

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• Convergent plate boundaries can occur when two
  continental plates push against each other. This
  collision produces high mountain ranges.

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• Convergent plate boundaries also occur when a
  continental plate and an ocean plate move against
  each other. Because the continental plate is
  thicker, it slides over the thinner ocean plate.
  The downward force of the lower plate causes
  molten rock to build up. Then, as magma, it
  erupts to form volcanic mountains.

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• Sometimes two plates do not meet head-on but
  move alongside each other. This creates a
  Transform plate boundary or fault. Violent
  earthquakes can occur near these faults.

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Secondary Landforms

• Landforms that are formed from the broken
  down remains of primary landforms are called
  secondary landforms. Primary landforms become
  secondary landforms through the process of
  erosion.

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Erosion

• Water is the most common force that erodes and
  shapes land
• Glaciers are large rivers of ice that have the
  force to move tons of rock.
• Wind can lift soil and carry it great distances
  and deposit it in dunes, and winds that carry
  sand can wear down rock.

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Examples of Primary and Secondary Landforms

• Mountains are primary landforms because they
  are created by tectonic activity. Over time,
  these mountains can be worn down by erosion to
  become hills. These hills would be secondary
  landforms.

Erosion
Primary Landform
Secondary Landform