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).