With suitable examples, discuss the various landforms associated with volcanic activities.
Volcano refers to a place from where gases, ashes and lave escapes out. Volcanic landforms are created by cooling of magma or lava.
When Magma cools inside the crust. The different types of intrusive landforms are:
- Batholith: Large granitic rock masses formed due to cooling down and solidification of hot magma in the crust. They develop in the shape of large domes and come to surface on denudation.
- Lacoliths : Large dome shaped body connected with pipe from below. In India, Karnataka Plateau domal hills are seen of granite rock.
- Lapolith: In this case when magma which is moving onhorizontal bed of a weak plane, if it takes saucer like shape, concave upwards.
- Phacoliths: Wavy mass at times found at base of synclines or top of anticlines.
- Sills: They are thicker horizontal deposits.
- Dykes : While magma moving through fissures and cracks solidifies perpendicular to ground and develops wall like structure. Commonly found found in western Maharashtra.
Extrusive Landforms are formed when lava cools down on the surface of earth.
- Conical Vent: Narrow cylindrical vent through which magma flows outmost common in composite volcanism.E.g Moun tFujiyama
- Mid-oceanic Ridges are formed when volcanic eruptions take place in ocean.
- Composite type landforms: They are conical type volcanic landforms .Along with andesitic lava, large quantities of pyroclastic material and ashes find their way to the ground. Mt Vesivius, Mount Fuji, Mount Etna
- Lava Plateaus: When thin magma flows out of a fissure and flows over the surface for a long time. For e.g Deccan trap, Snake Basin in USA
- Caldera Lake : Formed by most explosive volcanoes and thus collapse on themselves. Collapsed depression known as Calderas. These turn in to lakes E.g Lake Toba in Sumatra, Lake Lonar in Maharashtra
- Cinder Cone: It is a steep conical hill of fragments pyroclastic material , ash etc E.g Paricutin in Mexico , Cerro Negro in Nicaragu