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Zone Fossil
Index fossils (also known as guide fossils or indicator fossils) are fossils used to define and identify geologic periods (or faunal stages). Index fossils must have a short vertical range, wide geographic distribution and rapid evolutionary trends. Another term, "zone fossil", is used when the fossil has all the characters stated above except wide geographical distribution; thus, they correlate the surrounding rock to a biozone In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxon, taxa, as opposed to a Lithostratigraphy, lithostratigraphic unit which is defined by the ... rather than a specific time period. See also * Biostratigraphy#Index fossils References {{Reflist he:מאובן#מאובן מנחה ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Fossils
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock 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 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 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 help identify biozones, as they make up the basic biostratigraphy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is the first and shortest period of the Mesozoic Era and the seventh period of the Phanerozoic Eon. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerinea
†''Nerinea'' is an extinct genus of fossil sea snails, marine gastropod molluscs in the clade Heterobranchia. Fossil record This genus is present from the Jurassic to the Cretaceous periods. Fossils are known from various localities of Europe, Africa, North America, South America, United States, Colorado river and New Zealand. Species Species in the genus ''Nerinea'' include:Itaru HAYAMI & Tomoki KASE 1977 ttp://www.um.u-tokyo.ac.jp/publish_db/Bulletin/no13/no13009.html ''PART I. PALEOZOIC AND MESOZOIC GASTROPODA'' Bulletin No.13. The University Museum, The University of Tokyo, Tokio. * '' Nerinea desvoidyi'' D'Orbigny, 1921 * '' Nerinea gachupinae'' Alencaster, 1977 * '' Nerinea higoensis'' Shikama & Yui, 1973 * '' Nerinea koikensis'' Shikama & Yui, 1973 * '' Nerinea naumanni'' Sugiyama & Asao, 1942 * '' Nerinea rigida'' Nagao, 1934 * '' Nerinea schickii'' - from Early Cretaceous, Albian - Syria * '' Nerinea shiidai'' Shikama & Yui, 1973 * '' Nerinea somaliensis'' Weir, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. The Jurassic constitutes the second and middle period of the Mesozoic, Mesozoic Era as well as the eighth period of the Phanerozoic, Phanerozoic Eon and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic magmatic province, Central Atlantic Magmatic Province (CAMP). The beginning of the Toarcian Age started around 183 million years ago and is marked by the Toarcian Oceanic Anoxic Event, a global episode of Anoxic event, oceanic anoxia, ocean acidification, and elevated global temperatures associated with extinctions, likely caused by the eruption of the Kar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perisphinctes Tiziani
''Perisphinctes'' is an extinct genus of ammonite cephalopod. They lived during the Middle to Late Jurassic epochs and serve as an index fossil Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. "Biostratigraphy." ''Oxford Reference: Dictionary of Biology ... for that time period. The species ''P. boweni'' was named after the English chemist and geologist E. J. Bowen (1898–1980). Distribution Cephalopods of species belonging to this genus have been found in the Jurassic of Antarctica, Argentina, Chile, Cuba, Egypt, Ethiopia, France, Germany, Hungary, India, Iran, Italy, Japan, Madagascar, Poland, Portugal, Russia, Saudi Arabia, Spain, Switzerland, the United Kingdom and Yemen. Gallery File:Perisphinctes (Prosososphinctes) virguloides (Waagen).jpg, ''Perisphinctes virguloides'' File:Perisphinctes cf choffati.JPG, '' Perisphinctes choffati'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inoceramus Labiatus
''Inoceramus'' (Greek: translation "fibrous shell" for the fibrous structure of the mineral crystals in the shell) is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly oysters of the extant genus '' Pteria''. They lived from the Early Jurassic to latest Cretaceous.''Inoceramus'' at .orgWard ''et al.'' "Ammonite and inoceramid bivalve extinction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
