- Context: Landscape evolution in deserts is primarily concerned with the formation and extension of pediments.
- Definition of Pediments: Pediments are gently inclined rocky floors located close to the foot of mountains, found either with or without a thin cover of debris.
- Formation Mechanism:
- They form through the erosion of the mountain front via a combination of lateral erosion by streams and sheet flooding.
- Erosion initiates along the steep margins of the landmass or along the steep sides of tectonically controlled steep incision features across the landmass.
- Slope Structure and Retreat:
- Once formed, pediments feature a steep wash slope followed by a cliff or free face above it.
- The steep wash slope and free face retreat backwards.
- This erosion method is referred to as the parallel retreat of slopes through backwasting.
- Backward Extension: Through this parallel retreat of slopes, the pediments extend backwards at the expense of the mountain front.
- Inselbergs: As the pediments extend backwards, the mountain gradually gets reduced, leaving behind an inselberg, which is a remnant of the mountain.
- Pediplains: Through this continuous process of reduction, high relief in desert areas is eventually flattened into low, featureless plains termed pediplains.
Reference Ncert Documents
https://ncert.nic.in/textbook/pdf/kegy206.pdf
https://ncert.nic.in/textbook/pdf/kegy205.pdf
