The Himalayas are basically young fold mountains.Huge amounts of sediments are deposited on the sea bed,forming horizontal layers.When these layers of sediments are compressed from both sides,they are squeezed and folded.Gradually they get uplifted and form fold mountains.The Himalayas,Alps,Andes and Rockies are young fold mountains formed in the recent geological ages.They are very high,with steep slopes and sharp,pointed peaks.

The Northern plains of India belongs to the group of Depositional plains.These are formed by deposition of materials in low-lying areas.The most common of such plains are the alluvial plains formed by the deposition of sand,silt and clay carried by the rivers.The Northern plains of India,formed by the river Indus,Ganga and Brahmaputra rivers.