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Ingta Formation
The Ingta Formation is a geological unit containing green sandstones and shales; it crops out in the Canadian Mackenzie Mountains. Its age is poorly constrained, though it straddles the Precambrian/Cambrian boundary. Below the boundary its ichnofauna comprises subhorizontal ''Planolites'' burrows; above it, '' Phycodes'' burrows immediately appear, with Nemakit-Daldyn SSFs appearing soon after. Stratigraphy The formation is overlain by either the Backbone Ranges Formation and the Vampire Formation, depending on the locality. These two formations have a common base with the Ingta formation, and both continue onwards until the base of the Sekwi Formation. Depositional environment The rocks are submarine, and were deposited in a nearshore to offshore location on the continental shelf, with no freshwater influence evident—although overlying units bear evidence of deltaic and braided river deposits. Palaeontology The formation has yielded a range of SSFs including eggs and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. 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. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phycodes
''Phycodes'' is a genus of moths in the family Brachodidae. Species * ''Phycodes celebica'' Kallies, 1998 * ''Phycodes chalcocrossa'' Meyrick, 1909 * ''Phycodes chionardis'' Meyrick, 1909 * ''Phycodes interstincta'' Kallies & Arita, 2011 * ''Phycodes maculata'' Moore, 1881 * ''Phycodes minor'' Moore, 1881 * ''Phycodes penitis'' Diakonoff, 1978 * ''Phycodes punctata'' Walsingham, 1891 * ''Phycodes radiata'' Ochsenheimer, 1808 * ''Phycodes substriata'' Walsingham, 1891 * ''Phycodes taonopa'' Meyrick, 1909 * ''Phycodes tortricina'' Moore, 1881 Former species * ''Phycodes adjectella'' Walker, 1863 * ''Phycodes albitogata'' Walsingham, 1891 * ''Phycodes bushii'' Arita, 1980 * ''Phycodes eucallynta'' Meyrick, 1937 * ''Phycodes limata'' Diakonoff & Arita, 1979 * ''Phycodes mochlophanes'' Meyrick, 1921 * ''Phycodes morosa'' Diakonoff, 1948 * ''Phycodes omnimicans'' Diakonoff, 1978 * ''Phycodes pseliota'' Meyrick, 1920 * ''Phycodes seyrigella'' Viette, 1955 * ''Phycodes superbella'' Rebe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Shelly Fauna
The small shelly fauna, small shelly fossils (SSF), or early skeletal fossils (ESF) are mineralized fossils, many only a few millimetres long, with a nearly continuous record from the latest stages of the Ediacaran to the end of the Early Cambrian Period. They are very diverse, and there is no formal definition of "small shelly fauna" or "small shelly fossils". Almost all are from earlier rocks than more familiar fossils such as trilobites. Since most SSFs were preserved by being covered quickly with phosphate and this method of preservation is mainly limited to the late Ediacaran and early Cambrian periods, the animals that made them may actually have arisen earlier and persisted after this time span. Some of the fossils represent the entire skeletons of small organisms, including the mysterious '' Cloudina'' and some snail-like molluscs. However, the bulk of the fossils are fragments or disarticulated remains of larger organisms, including sponges, molluscs, slug-like halkierii ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sekwi Formation
The Sekwi Formation is a geologic formation in Northwest Territories, Canada, which preserves fossils dating back to the Cambrian period. The formation principally comprises shallow water carbonates, but deepens to include mid-shelf mudstones, both calcareous and siliciclastic. It dates from c. 525-510 Ma, the ''Nevadella'' / ''Bonnia-Olenellus'' trilobite zones. See also * List of fossiliferous stratigraphic units in Northwest Territories This is a list of fossiliferous stratigraphic units in the Northwest Territories, Canada. References * {{Lists of fossiliferous stratigraphic units in Canada * Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''N ... References * Cambrian Northwest Territories Cambrian southern paleotropical deposits {{Northwest Territories-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protohertzina
''Protohertzina'' is a genus of conodonts (protoconodonts or paraconodonts) or, possibly, Chaetognaths, found at the beginning of the Cambrian explosion. Protoconodonts are an extinct taxonomic group of conodonts.Zooproblematica and mollusca from the Lower Cambrian Meishucun section (Yunnan, China) and taxonomy and systematics of the Cambrian small shelly fossils of China. P. Y. Parkhaev and Y. Demidenko, Paleontological Journal, 2010, volume 44, issue 8, pages 883-1161, Chaetognaths (also known as arrow worms) were thought possibly to be related to some of the animals grouped with the conodonts. The conodonts themselves, however, are thought to be related to the vertebrates. It is now thought that protoconodont elements (e.g., ''Protohertzina anabarica'' Missarzhevsky, 1973), are probably grasping spines of chaetognaths rather than teeth of conodonts. ''Protohertzina'' fossils have been found in the Ingta Formation of Canada. Use in stratigraphy The earliest known fossils ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
