Distinguish between Tilted Block mountains and Lifted Block mountains :-

(i) Magma and Lava : 

Magma : 

1. Magma is hot sticky molten material. 

2. It contains solutions of water and gases. 

3. It comes out during volcanic eruptions. 

Lava : 

1. Lava is solidified magma.

2. Gases and water disappear after evaporataion. 

3. It cools down as it comes into contact with atmosphere. 

(ii) Acidic Lava and Basic lava 

Acidic Lava :

1. It is highly viscous lava. 

2. It is light coloured like granite. 

3. It has low density. 

4. It has a high percentage of silica. 

5. It flows slowly and results in steepsided cones or lava domes.

Basic Lava : 

1. It is highly fine and thin. 

2. It is dark coloured like Basalt. 

3. It has high density. 

4. It is poor in silica. 

5. It flows rapidly as thin sheets resulting in shield cones.

  (iii) Cinder Cone : Volcanic cones are called Cinder cones when the material erupted consists of cinder and other solid particles. These cones have steep slopes because they consist of particles of large size. 

Composite Cone : The volcanoes which start as cinder cone and grown into large volcanic hills with alternating layers of lava and ash are called Composite cones. These cones are formed due to an explosive eruption followed by eruption of lava. Explosive eruption leads to the formation of a layer of ash while lava solidifies as a sheet on the layer of ash. This is followed by a quiet period and then the process gets repeated. 

(iv) Fissure type of volcanoes : A volcano is a vent in the earth’s crust out of which hot molten rocks (lava) flow. The hot rocks may also eject violently in the form of solid pieces. If the vent is in the form of a long crack then it is known as a Fissure Type Volcano. In this type volcanic activity occurs quietly the lava upwells silently and spreads over a large area giving rise to volcanic plateaux and extensive lava sheets. 

Central-type Volcanoes : If the vent in the earth’s crust is of such type that the rock materials come out and mounds hills or cones are formed than the volcanoes formed are known as Volcanoes of the Central type. Vesuvius and Fuji Yama are the best examples of this type. 

(v) Crater and Caldera : Crater forms the summit and Caldera the enlarged mouth or the sunken crater at the centre of a volcano. When water accumulates in a crater it forms a crater lake and in a caldera a lake like Taba lake of Sumatra. A crater is formed as a result of overflow of lava and calera as a result of subsidence. 

(vi) Laccoliths : Laccoliths are large lens-shaped intrusions which assume a dome shape. They vary in thickness and extent. When laccoliths are exposed on the surface they form low hills. 

Lapoliths : Lapoliths are saucer-shaped intrusive layer of solidified magma and sinks as shallow basins in rock-beds. 

(vii) Hot Springs : 

1. It is a stream of hot water issuing from the ground. The hot water flows unobstructed quietly and continuously. 

2. Hot springs are common where joints fissures and porous beds allow the free exit of water to the surface. The water becomes hot when it comes into contact with the heated rocks or upper heated steam lying deep into the earth’s crust.

Geysers : 

1. It is a hot spring which at regular or irregular intervals throws a jet of hot water and steam into the air. 

2. In the case of geyser the fissure or vent connecting the source of hot water to the surface is very narrow which greatly increases the pressure and temperature of the hot water and so when water comes out it rise high into the air.