Question

Rift valleys are bounded by steep sides
slopes of block mountains and have a flat floor. Give reasons
Or proof it.

Answer 1

Block Mountains or Fault Block Mountainsare massive in structure. They have very steep slopes. Generally, the topography of the Block Mountains is very smooth. They are usually tucked in the folded zones of some of the most primitive mountains. These folded zones have gradually lost their plastic properties. And as a result, mountain surfaces have been smoothened because of denudations. Tectonic actions continued and eroded these sections. After breaking, some of the sections rose to new ranges and horsts. The remaining sunk to form depressions and grabens. Due to the repeated actions of orogeny, they formed broad gently sloping folds. These folds were accompanied by faults. Lifted type Block Mountains has two steep sides exposing scarps on both the sides.