ARID CYCLE OF EROSION

1. Initial Stage

• During the first stage of the arid cycle of mountain-grit desert erosion, the climate is very dry (less than 25 cm of rain a year on average), deserts rise up by folding or faulting, intermountain basins form, inland and centripetal drainage starts, and so on.
• Initially, the intermontane basins (of tectonic origin) had their own drainage system, with no drainage communication between them.
• The centers of isolated intermontane basins become erosional base levels.
• Evaporation is a very dynamic process. The playa is produced as a result of water buildup in the basins' centers.
• The vast majority of streams are tributary and drain into the enclosed basins.
• The erosion cycle begins with the decline of mountains and the filling (by sedimentation) of basins.

2. Youth Stage

• Because erosion and deposition occur in tandem, the early reliefs are progressively eroded owing to mountain erosion and basin filling.
• Because of backwasting and downwasting, the water divides steadily narrower and lower.
• The lower areas of hillslopes are more strongly eroded by rill and gully erosion caused by rainstorms.
• There are definitely two zones of geomorphic significance

1. the degradation zone on higher lands, and
2. the aggravation zone (of the basins). 

• Alluvial fans form on the edges of the enclosed basins. Bajadas form as a consequence of the confluence of several alluvial fans.
• Wind deflation occurs when there are loose sands present.
• Deflation causes smaller depressions, known as blowouts.
• A playa lake forms at the basin's core.
• Sand dunes grow here and there along the playa's edges.
• By the conclusion of the young period, relief had considerably decreased.

 3. Maturity Stage

• Relief is gradually diminishing owing to the slow erosion of mountain divides and the filling of enclosed basins.
• The progressive retreat of water increases the size of enclosed basins.
• The level of these basins rises due to gradual sedimentation. Upslope, the bajadas become progressively richer, enlarged, and extended.
• Extensive rock-cut pediments occur between retreating mountain fronts and the bajada zone.
• Mountain divisions are being breached as a result of their gradual decline. This strategy results in basin and drainage system integration.
• As streams that have crossed the divides between them drain water from the higher basins into the lower basins, the latter become tributaries to the former.
• Sand deflation becomes more vigorous. This method produces bare surfaces, such as desert pavements.

4. Old Stage

• All of the highlands have been reduced to an almost flat landscape with relatively low heights.
• Several surviving hills rise above the flat desert landscape.
• These tiny hills, known as inselbergs or bornhardts, resemble islands in vast deserts.
• Wind-driven sand deflation is the most active.
• Several pediments unite to generate enormous pediplains.

IMAGE SOURCE (THUMBNAIL)