What do you understand by sediment ? On the basis of nature of sediment, how many kinds of sedimentary rocks may be formed ?

The word sedimentary is derived from the Latin word sedimentum which means settling.

On the basis of sediments, the sedimentary rocks are of three types.

1. Mechanically formed sedimentary rocks.

2. Organically formed sedimentary rocks.

3. Chemically formed sedimentary rocks.

1. Mechanically formed sedimentary rocks : These are formed due to various weathering processes especially mechanical weathering processes. The rock breaks in various sizes of fragments. They are also called clastic sedimentary rocks.

2. Organically formed sedimentary rocks : These are formed by the active participation of animals and plants through their secretions or formed out of dead remains of organisms. These are non-clastic in nature.

3. Chemically formed sedimentary rocks : Solidified precipitation from chemical solutions forms these rocks. These are also non-clastic rocks like the organically formed ones.