Dating principles stratigraphy environments of deposition
Stratigraphy is a branch of geology concerned with the study of rock layers strata and layering stratification. It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has two related subfields: lithostratigraphy lithologic stratigraphy and biostratigraphy biologic stratigraphy. Catholic priest Nicholas Steno established the theoretical basis for stratigraphy when he introduced the law of superposition , the principle of original horizontality and the principle of lateral continuity in a work on the fossilization of organic remains in layers of sediment.
Sedimentary rocks generally occur in layers that reflect the pattern of sedimentation of the original sediments. This layering of sedimentary rocks is referred to as stratification. In , Steno stated three basic principles for chronological analysis of the rock record which have proven to be extremely useful in the study of earth history. Strata that are inclined or folded must have suffered disturbance subsequent to deposition. Rocks of a certain age contain one set of fossils that differ from fossils in rocks of different ages. Figure 9. Rock exposures often are separated by great distances.