In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock record. In most cases, the environments associated with particular rock types or associations of rock types can be matched to existing analogues. However, the further back in geological time sediments were deposited, the more likely that direct modern analogues are not available (e.g. banded iron formations).
A diagram of various depositional environments
Types of depositional environmentsEdit
Diagram to show the different depositional environments in which tsunami deposits are formed – partly after Shanmugam 2006 
Depositional environmental model of the Araripe Basin formations, NE Brazil
Deltaic – Silt deposition landform at the mouth of a river (possible cross beds, ripple marks) Common sediments are sand, silt, and clay.
Tide – Rise and fall of the sea level under astronomical gravitational influences – processes due to tidal currents, creates tidal flats (fine-grained, ripple marks, cross-beds). Common sediments are silt and clay
Lagoonal – Shallow body of water separated from a larger body of water by a narrow landform. Little transportation, creates lagoon bottom environment. Common sediments are carbonates (in tropical climates).
Beach – Area of loose particles at the edge of the sea or other body of water. Caused by waves and longshore currents. Creates beaches, spits, and sandbars with the common sediments of gravel and sand.
Shallow water marine environment – processes due to waves and tidal currents, creates shelves and slopes, lagoons. Common sediments are carbonates (in tropical climates) or sand, silt, and clay (elsewhere)
Upper shoreface – Portion of the seafloor that is shallow enough to be agitated by everyday wave action
Deep water marine environment – Flat area on the deep ocean floor (abyssal plains) caused by ocean currents. Common sediments are clay, carbonate mud, silica mud.
Reef – A shoal of rock, coral or other sufficiently coherent material, lying beneath the surface of water caused by waves and tidal currents. Also creates adjacent basins. Common sediments are carbonates.
Evaporite – Water-soluble mineral deposit formed by evaporation from an aqueous solution