Hydration
Topic: Geomorphic Processes: Weathering, Mass Movement, Erosion and Soil Formation · NCERT: Class 11, Ch 5 "Geomorphic Processes"
Meaning
Hydration is a type of chemical weathering. Water joins chemically with a mineral and becomes part of it. The mineral swells, which puts stress on the rock and weakens it. For example, anhydrite (calcium sulphate without water) becomes gypsum, and feldspar slowly changes into clay. When rock is wetted and dried again and again, it keeps swelling and shrinking until it crumbles. Clay is the material most affected by hydration.
Example
In the granite of the Karnataka plateau, feldspar grains take in water and change slowly to clay. The rock surface loosens into gritty, crumbly material.
Don't confuse with
- Solution: in solution the mineral dissolves and is carried away. In hydration the mineral stays where it is but takes in water and swells.