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Taxon-range Zone
In biostratigraphy, a subdiscipline of geology, a taxon-range zone is the zone between the highest and the lowest stratigraphic occurrence of a taxon. Taxon-range zones are one of the fundamental biozones used in biostratigraphy and are named after the taxon whose range they describe. Definition The International Commission on Stratigraphy defines a Taxon-range zone as follows: "The body of strata representing the known range of stratigraphic and geographic occurrence of specimens of a particular taxon. It is the sum of the documented occurrences in all individual sections and localities from which the particular taxon has been identified." So a taxon-range zone is not only a vertical interval, but expands laterally. Taxon-range zones are limited at the top by the surface that connects all highest known stratigraphic occurrences of the taxon and are limited at the bottom by the surface that connects all lowest known stratigraphic occurrences of the taxon. Local Range The local ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biostratigraphy
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock Stratum, strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Biology'', 8th ed., Oxford University Press, 2019. The primary objective of biostratigraphy is ''correlation'', demonstrating that a particular Horizon (geology), horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the Sedimentary depositional environment, sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology, and so is treated as one major aspect of integrated Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates. Geologists broadly study the properties and processes of E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Historical development 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. The first practical large-scale application of stratigraphy was by William Smith (geologist), William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized the significance of Stratum, strata or rock layering and the importance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxon
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's Linnaean taxonomy, system in ''Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard de Jussieu, Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first mad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biozone
In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties of the surrounding rock. A biostratigraphic unit is defined by the zone fossils it contains. These may be a single taxon or combinations of taxa if the taxa are relatively abundant, or variations in features related to the distribution of fossils. The same strata may be zoned differently depending on the diagnostic criteria or fossil group chosen, so there may be several, sometimes overlapping, biostratigraphic units in the same interval. Like lithostratigraphic units, biozones must have a type section designated as a stratotype. These stratotypes are named according to the typical taxon (or taxa) that are found in that particular biozone. The boundary of two distinct biostratigraphic units is called a ''biohorizon''. Biozones can be furthe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Commission On Stratigraphy
The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphy, stratigraphical, geology, geological, and chronology, geochronological matters on a global scale. It is the largest subordinate body of the International Union of Geological Sciences (IUGS). The ICS is essentially a permanent working committee, working subcommittee, which meets far more regularly than the quadrennial meetings scheduled by the IUGS, when it meets as a congress or committee, membership of the whole. Aims One of its main aims, a project begun in 1974, is to establish a multidisciplinary standard and global geologic time scale that will ease paleontology, paleontological and geobiology, geobiological comparisons region to region by benchmarks with stringent and rigorous strata criteria called Global Boundary Stratotype ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Range Offset
In geology, range offset is the time difference between the last fossil occurrence of a taxon and the actual disappearance of this taxon. Range offset can be used as a measure of Biostratigraphy, biostratigraphic precision and determines among others how much information about extinctions can be derived from fossil occurrences. Definition The range offset of a taxon is defined as * the time span between the moment in which the highest stratigraphic occurrence of said taxon was deposited and the moment in which the taxon disappeared from the locality or area and/or * the time span between the moment the taxon appears for the first time in the locality or area and the moment in which the lowest stratigraphic occurrence of said taxon was deposited. Effects of sequence stratigraphy Range offset is strongly affected by sequence stratigraphy. Simulations show that range offset changes by up to three orders of magnitude dependent on the position in the systems tracts. References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
