stratigraphy, branch of geology specifically concerned with the arrangement of layered rocks (see stratification stratification (Lat.,=made in layers), layered structure formed by the deposition of sedimentary rocks . Changes between strata are interpreted as the result of fluctuations in the intensity and persistence of the depositional agent, e.g.
..... Click the link for more information. ). Stratigraphy is based on the law of superposition, which states that in a normal sequence of rock layers the youngest is on top and the oldest on the bottom. Local sequences are studied, and after considering such factors as the average rate of deposition of the different rocks, their composition, the width and extent of the strata, the fossils contained, and the periods of uplift and erosion, the geological history of the sequence is reconstructed. These sequences are then correlated to those of similar age in other regions with the ultimate aim of establishing a consistent geochronology for the entire earth. Statigraphy is therefore important in the relative dating dating, the determination of the age of an object, of a natural phenomenon, or of a series of events. There are two basic types of dating methods, relative and absolute.
..... Click the link for more information. of all types of rock. In areas where the strata have undergone folding, faulting, and erosion, stratigraphic techniques are used to determine their correct sequence. The principle of included fragments in stratigraphy states that any rock fragment included in another rock must be older than the surrounding rock. Fossils have been the most important means of correlation because, as a result of evolution evolution, concept that embodies the belief that existing animals and plants developed by a process of gradual, continuous change from previously existing forms. This theory, also known as descent with modification, constitutes organic evolution.
..... Click the link for more information. , rock strata of approximately equal age exhibit similar flora and fauna. Dating and correlation of stratified rocks by means of fossils is called stratigraphic paleontology. See also dating.

Bibliography

See B. Kummel, History of the Earth (1961); E. W. Spencer, Basic Concepts of Historical Geology (1962); R. K. Matthews, Dynamic Stratigraphy (1974); P. C. Cattermole and P. Moore, The Story of the Earth (1985).

stratigraphy

Scientific discipline concerned with describing rock successions and interpreting them in terms of a general time scale. It provides a basis for historical geology, and its principles and methods are applied in such fields as petroleum geology and archaeology. Stratigraphic studies deal primarily with sedimentary rocks but may also encompass layered igneous rocks (e.g., those resulting from successive lava flows) or metamorphic rocks formed either from such extrusive igneous material or from sedimentary rocks.

stratigraphy [strə′tig·rə·fē]

(geology)

A branch of geology concerned with the form, arrangement, geographic distribution, chronologic succession, classification, correlation, and mutual relationships of rock strata, especially sedimentary. Also known as stratigraphic geology.

stratigraphy (redirected from stratigraphically)

Bibliography

stratigraphy

stratigraphy
(redirected from stratigraphically)