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Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneous or sedimentary relating to how the rock was formed.
Engraving from William Smith's monograph on identifying strata based on fossils. 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 1669 work on the fossilization of organic remains in layers of sediment.
It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. [1] [2] A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form.
Bed in lithostratigraphy [ edit ] According to both the North American Stratigraphic Code and International Stratigraphic Guide, a bed is the smallest formal lithostratigraphic unit that can be used for sedimentary rocks.
In Dutch lithostratigraphy, the name Lias has no official status, however, it is often used for the lower part of the Altena Group in the subsurface of the Netherlands and the southern North Sea. [8] In northern Germany, the Lias Group consists of nine formations (from top to base): [9] Opalinuston; Dörnten-Formation; Posidonia Shale; Amaltheenton
The Germanic Trias Supergroup (German: Germanische Trias-Supergruppe) is a lithostratigraphic unit (a sequence of rock strata) in the subsurface of large parts of western and central Europe (north of the Alps) and the North Sea.
Seven of the study participants developed NAION, which Katz explained is a stroke of the optic nerve — the nerve that connects your eye to your brain — potentially causing irreversible vision ...
The geological timescale has all systems in the Phanerozoic eonothem subdivided into series. Some of these have their own names; in other cases a system is simply divided into a Lower, Middle and Upper series, with official series being capitalized and unofficial designations (such as "middle Cretaceous") being left uncapitalized.