Question 5
Give reasons for the following:
(a) Southern ocean is not navigable.
(b) Young fold mountains have high peaks.
(c) Rift Valley has steep sides.
(a) Southern Ocean is not navigable because it remains frozen for the most part of the year.
(b) Young fold mountains have high and pointed peaks because they are younger and have not been much eroded by wind or water. On the contrary, old fold mountains have been subjected to the forces of denudation (such as weather, rivers, glaciers) for a longer geological period. Due to this prolonged erosion, they are lower in height and have round peaks.
(c) Rift valley have steep sides because they are formed as a linear depression or trough by the sinking of the intermediate crustal rocks between two or more parallel faults. Sudden rifting of tectonic plates leads to steep sides of Rift valley.