There are different types of chemical weathering, the most important are:
Solution - removal of rock in solution by acidic rainwater. In particular, limestone is weathered by rainwater containing dissolved CO2, (this process is sometimes called carbonation).
Hydrolysis - the breakdown of rock by acidic water to produce clay and soluble salts.
Oxidation - the breakdown of rock by oxygen and water, often giving iron-rich rocks a rusty-coloured weathered surface.
A landmass formed within a river is known as riverine islands. Riverine islands are formed when rocks and mud gets deposited in the river bed by flowing rivers.
