Sedimentology encompasses the study of modern sediments such as sand,[1] silt, and clay,[2] and the processes that result in their formation (erosion and weathering), transport, deposition and diagenesis.
The premise that the processes affecting the earth today are the same as in the past is the basis for determining how sedimentary features in the rock record were formed.
[citation needed] The principle of superposition is critical to the interpretation of sedimentary sequences, and in older metamorphic terrains or fold and thrust belts where sediments are often intensely folded or deformed, recognising younging indicators or graded bedding is critical to interpretation of the sedimentary section and often the deformation and metamorphic structure of the region.
The methods employed by sedimentologists to gather data and evidence on the nature and depositional conditions of sedimentary rocks include; The longstanding understanding of how some mudstones form has been challenged by geologists at Indiana University (Bloomington) and the Massachusetts Institute of Technology.
"[7] Macquaker and Bohacs, in reviewing the research of Schieber et al., state that "these results call for critical reappraisal of all mudstones previously interpreted as having been continuously deposited under still waters.