The mountains which were formed over 250 million years ago due to compression of earth’ crust are called old fold mountains. They have gentle slopes and low altitude due to weathering overtime e.g. Urals in Russia, Aravallis in India and Appalachians in India. The recently formed mountains i.e. about 25 million years ago are called young fold mountains. They are rugged and lofty. They comprise the world’ highest mountain ranges.
E.g. Rockies of North America, Alps, Andes, Himalayas and The great Dividing Range.
