Basic Concept of Mountains.

DEFINITION :-

A mountain may be defined as a huge landmass on the earth's surface,attending a great height above the surrounding with a series of oranges and loftly crests and peaks covered with snow.

DESCRIPTION :-

A mountain is a highland area with a series of ranges and peaks.It has many gorges and valleys.Between the high ranges,there are intermont plateaus.High mountains are regions of glacical activity.

FORMATION :-

Mountains are formed in various ways.They are formed by wrinkling up the earth,s surface.Giving away heat from its body,the earth wrinkles.As a result,compression and contraction take place and folds,fractures and faults are formed in the rock-beds which in time build up mountains and valleys.Volcanic eruption erects volcanic mountains.Erosional agents ( The sun,the rain,,the wind and the running water) wear away the soft rocks of the highlands ; the high resistant rocks are left there as erosional mountain.

An eminent German, Prof Alfred Wegner (1912) explained in his 'Continental Drift Theory ' how the mountains were formed .According to his theory,the lighter rocks-beds are in a floating state on the heavier rock-masses.In the primitive world there was a single landmass called 'Pangaea'.Natural forces broke it down into pieces ; the major pieces are know as continents.In time, they drifted apart. As they drifted away, the horizontal pressure pushed the rock-beds to form fold ; harder rock beds got fracture and faulting occurred. Thus the drifting of the continents caused the formation of the fold mountains and other landforms.

In the recent years, "Plate Tectonic Theory" has become popular. It has developed the idea on the former. This theory states that the continents and the oceanic beds consist of a series of plates; the continents plates are floating on the oceanic plates. The get motion when disturbances occur in the interior of the earth; sometimes intrusion takes place from the interior to the upper layer and the plates begin to move. As the plates move towards each other, friction sometimes occurs. It exerts pressure which forces the rock-beds to bend and thus (i) folds (ii) Faults and (iii) Eruption occur, resulting in the formation of mountains and different types of landform.

Classification of Mountain :-

Mountain can be classified into four major types, according to their mode of formation : (i) Fold mountain (ii) Block mountain (iii) Volcanic mountain and (iv) Relict mountain or Erosional mountain.