Simplistically, the earth's surface can be divided into two broad divisions on the basis of whether there is net erosion or deposition:
(1) Sourcelands - areas which are sources of sediment, usually meaning mountainous regions, but including any place erosion and sediment removal takes place, and
(2) Depositional Basins - areas which receive eroded sediment.
Depositional basins are subdivided a number of ways.
One is by the predominant sediment type found in the basin; thus, Siliciclastic Dominated Systems and Carbonate Dominated Systems. A general observation we can make is that sediment type and supply changes from the sourceland to the depositional basin such that depositional environments evolve in systematic and predictable sequences from sourceland to depositional basin. In general, depositional environments and thus rock types are predictable from sourceland to depositional basin. Each exists in a specific location for specific reasons.
Another, more useful method, is to categorise depositional environments according to their location and by the erosional/depositional processes which distinguish them. A depositional environment is a portion of the earth's surface characterized by a unique combination of physical, chemical, and biological processes. These processes control how sediment is transported and deposited, what chemical modification it undergoes, and what kind of organisms live in and affect the sediment. The processes result in the characteristic and distinctive sedimentary deposits typical of each environment by which we recognize and identify them. Several dozen depositional environments have been identified. The more common ones are listed in the table below.
There are three major environments of deposition: Terrestial/Continental, Transitional and Marine.
Carbonate dominated systems occur usually in tectonically stable regions where the supply of siliciclastic sediment is minimal or non-existent.
after: Lynn S. Fichter, James Madison University, USA.