Diastrophism
Topic: Geomorphic Processes: Weathering, Mass Movement, Erosion and Soil Formation · NCERT: Class 11, Ch 5 "Geomorphic Processes"
Meaning
Diastrophism covers all the processes that move, raise or build up parts of the earth's crust. It has four parts:
- orogeny: mountain building;
- epeirogeny: broad uplift of large areas;
- earthquakes: local, fairly minor movements;
- plate tectonics: sideways movement of crustal plates.
All of these can fault (break) and fracture rocks. The pressure and heat changes they cause also lead to metamorphism, which turns one rock into another.
Example
The Narmada valley in central India is a rift valley. It formed when a strip of crust sank between faults, which is a result of diastrophism.
Don't confuse with
- Gradation: this wears relief down through erosion and deposition. Diastrophism builds and moves the crust.