Which of the following landforms is formed due to faulting?

Concept: Landforms are classified by the geomorphic process that shapes them: tectonic movement (folding and faulting of rock strata), erosion (wind, water, or ice wearing rock away), deposition (debris laid down by glaciers, rivers, or wind), or solution/karst action (dissolution of soluble rock such as limestone). Faulting itself is the fracturing and relative displacement of rock blocks along a fault plane; when a block of crust subsides between two roughly parallel normal faults, the down-dropped block forms a rift valley (graben), flanked by uplifted blocks called horsts.

Application: Among the four landforms listed, only the rift-valley arises from this tectonic faulting process: the crustal block between the bounding faults has dropped down relative to the flanking blocks, producing the characteristic elongated, steep-sided depression.

Contrast: The other three landforms are produced by entirely different processes, not by fault movement:

• Mushroom rock is shaped by wind erosion, which undercuts the softer base faster than the harder top in arid regions -- an erosional process, not a tectonic one.

• Moraine is a ridge or mound of rock debris (till) deposited directly by a glacier as it advances or retreats -- a depositional landform.

• Doline is a sinkhole formed where percolating water dissolves soluble rock such as limestone, followed by surface collapse -- a karst/solution landform.

Rift valleys such as the East African Rift Valley and India's Narmada-Tapi rift are classic examples of landforms produced by faulting, confirming rift-valley as the landform formed due to faulting.