Intrusive and Extrusive Volcanic Landforms

Two types of landforms are created by volcanic eruptions, Intrusive and Extrusive Landforms. Extrusive landforms are formed on the surface of the Earth, while intrusive landforms are formed in the Earth’s interior.

Intrusive and Extrusive Volcanic Landforms

Extrusive Landforms

  • Extrusive landforms formed due to volcanic eruptions are
  • Conical hill: A cone-shaped hill is a typical example of an extrusive landform.
  • Cone: A cone is formed when rock materials and debris are thrown away by a volcanic eruption.
  • Crater: It is a bowl-shaped depression formed at the mouth of a volcano. It is formed due to the repeated eruption of a volcano.
  • Caldera: Because of the repeated eruption of a volcano, its summit may be blown away a number of times. In its place a large depression called caldera is formed.
  • Composite cone: When a volcano throws away both lava and large fragments of rocks during eruption, multiple layers of these two materials build up, resulting in the formation of a composite cone.
  • Volcanic shield: When lava gets solidified after flowing away from the vent, it forms a broad summit with a gentle base leading to the formation of a volcanic shield.
  • Lava plateau: A plateau is formed when a volcano constantly erupts over a long time at frequent intervals over a large area throwing away lava and fragments of rocks (pyroclasts). The Deccan Plateau is one such example.

Intrusive Landforms

  • Intrusive landforms formed due to volcanic eruptions are
  • Dykes: These are vertical intrusions of igneous rocks. They are formed when magma force the rock apart under the surface of the Earth.
  • Lopoliths: These are saucer-shaped intrusions which occur between the layers of sedimentary rocks.
  • Sill: A sill is a terrace-like feature which is formed between the beds of sedimentary or igneous rocks.
  • Batholiths: It is the large-sized intrusions in igneous rocks at great depths. They come out to the surface of the Earth during the mountain-building activity.
  • Laccoliths: These are dome-shaped intrusive landforms which forces the upper part of the rock to bulge upwards. The erosion and denudation of the Earth’s surface bring laccoliths to the surface of the Earth.
  • Phacolith: These are small structures which cool down and solidify near the crest of an anticlinal fold.

Also, Read Landforms of the Earth

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