- Volcano, an extrusive feature formed from the accumulation of erupting lava and/or volcanic ash.
- Volcanoes are found at both constructive and destructive margins and the distribution follows the pattern of the plate boundaries. Volcanoes at destructive margins erupt more violently but less frequently than those found at constructive margins. Another location for volcanoes is hot spots; this is the least common type.
- Constructive margins – Basaltic/Basic Lava (shield volcanoes).
- Destructive margins – Andesitic/ Acid Lava (composite cone).
- Has a low viscosity and is hot 1200C and is runny like warm treacle?
- Viscous, less hot 800C, flows more slowly and over shorter distances.
- Has a low silica content?
- Higher silica content.
- Takes a longer time to solidify, travels further.
- Soon cools and solidifies, flowing over short distances.
- Retains its gas content which makes is mobile.
- Loses gases quickly and becomes viscous.
- Produces extensive but gently sloping landforms.
- Produces steep-sided, more localised features.
- Eruptions are frequent but relatively gentle.
- Eruptions are less frequent but are violent due to the build-up of gases.
- Lava and steam ejected.
- Ash, rocks, gases, steam and lava ejected.
- The shield volcano:This is a broad, shallow volcanic cone, which arises because the running lava, which is fluid and hot, cools slowly.
- The dome volcano:This one has a steep, convex slope from thick, fast-cooling lava
- The ash-cinder volcano:Throws out – besides lava – much ash into the air. Through this the volcanic cone is built up from alternate layers of ash and cinder.
- The composite volcano:These are also built up from alternate layers of lava and ash but, besides its main crater, it has many little craters on its slope.
- The caldera volcano:An older volcano with a large crater which can be 62 miles (100km) wide. In this crater many little new craters are formed.
- Cinder Cone: Cinder cones are among the most common volcanic landforms found in the world they are small cones consisting predominantly of tephra that result from strombolian eruptions relatively low-level volcanic eruptions.
- They usually consist of basaltic to andesitic material, which means the lava is more viscous, and therefore results in shorter and thicker flows. They are generally formed when ash and cinder build up into a symmetrical cone. The most famous cinder cone is Paricutin which grew out of a corn field in Mexico in 1943
- Extrusion- the upward movement of magma through the earth’s crust and onto its surface as lava. Extrusive volcanic landforms form once the lava has cooled and hardened.
- Intrusion- the movement of magma underground into spaces that exist within rock strata. When this magma cools and hardens, intrusive volcanic landforms are created. Weathering and erosion cause these landforms to be exposed.