With the aid of diagrams, describe the characteristic and mode of formation of any two of the following:
(a) Rock pedestal (b) Yardang (c) Mesa
Explanation
(a) ROCK PEDESTALS:Characteristics:
- It has soft and hard rock layers, mushroom with irregular shape formed in desert e.g Sahara desert
- The soft rock layers is eroded more rapidly resulting in the formation of irregular edge of alternate bands of hard and soft rock.
- Further erosion at the base produces a mushroom-shaped feature .
(ii) YANDANG: This is an erosional feature formed by wind abrasion in desert e.g Atacama desert. It has vertical bands or hard and soft rocks of height between 5-15cm.Characteristics:
- Yandang is found in the desert.
- Vertical bands of hard and soft rocks standing in the direction of prevailing wind is eroded such that Rock the softer rock is eroded faster than the hard rock resulting in the formation of Yandang.