Glaciation
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References: Waggoner 1998,[1] Hofmann 1990[2]
The Ediacaran Period (IPA: /ˌiːdiˈækərən/, named after the Ediacara Hills of South Australia) is the last geological period of the Neoproterozoic Era, just preceding the Cambrian Period of the Paleozoic Era. Ediacara Hills are a range of low hills in the northern Flinders Ranges of South Australia, around 650 km north of Adelaide. South Australia is a state of Australia in the southern central part of the country The Neoproterozoic Era is the unit of geologic time from 1000 to 542 +/- 0 The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life" Its status as an official geological period was ratified in March 2004 by the International Union of Geological Sciences (IUGS) and announced on May 13, 2004, the first new geological period declared in 120 years. The International Union of Geological Sciences (IUGS is an international Non-governmental organization devoted to international cooperation in the field of Geology Events 1497 - Pope Alexander VI excommunicates Girolamo Savonarola. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " [3][4] The type section is in the Flinders Ranges in South Australia. A Global Boundary Stratotype Section and Point, abbreviated GSSP, is an internationally agreed upon stratigraphic section which serves as the reference section for The Flinders Ranges is South Australia 's largest Mountain range which starts approximately 200 km north west of Adelaide. It overlaps, but is shorter than the Vendian period, a name that was earlier proposed in Russia. Russia (Россия Rossiya) or the Russian Federation ( Rossiyskaya Federatsiya) is a transcontinental Country extending
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Base of the Ediacaran
Although the Ediacaran Period does contain soft bodied fossils, it is unusual in comparison to later periods because its beginning is not defined by a change in the fossil record. FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. Rather, the beginning is defined at the base of a chemically distinctive carbonate layer, referred to as a "cap carbonate", because it caps glacial deposits and indicates a sudden climatic change at the end of an ice age. In Chemistry, a carbonate is a salt or Ester of Carbonic acid. Cap carbonates are layers of distinctively textured Carbonate rocks which typically form the uppermost layer of Sedimentary sequences reflecting major glaciations "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. An ice age is a period of long-term reduction in the Temperature of the Earth 's surface and atmosphere resulting in an expansion of continental Ice sheets This bed is characterized by an unusual depletion of 13C, and is considered by many scientists to be of global extent, although this is controversial. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6
Dating
No dating has been possible at the type section of the Ediacaran Period in South Australia. Absolute dating is the process of determining a specific date for an archaeological or palaeontological site or artifact Therefore the age range of 635 to 542 million years before the present is based on correlations to other countries where dating has been possible. The base age of approximately 635 million years ago is based on U-Pb (uranium-lead) isochron dating from Namibia. Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Isochron dating is a common technique of Radiometric dating and is applied to date certain events such as Crystallization Metamorphism, shock events and Namibia, officially the Republic of Namibia, is a country in Southern Africa on the Atlantic coast [5] Applying this age to the base of the Ediacaran assumes that individual cap carbonates are synchronous around the world and that the correct cap carbonate layers have been correlated between Australian and Namibia. This is controversial because an age of about 580 million years has been obtained in association with glacial rocks in Tasmania which some scientists tentatively correlate with those just beneath the Ediacaran rocks of the Flinders Ranges. Tasmania is an Australian island and state of the same name It is located south of the eastern side of the Continent, being separated from it by Bass [6] The age of the top is the same as the widely recognised age for the base of the Cambrian Period. The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with [4]
Biota
The animal fossil record from this period is sparse, possibly because animals had yet to evolve hard shells, which make for easier fossilization. The Ediacara (ˌiːdɪˈækərə formerly Vendian) biota are ancient lifeforms of the Ediacaran Period which represent the earliest known complex The Ediacaran biota include the oldest definite multicellular organisms with tissues, and the most common types resemble segmented worms, fronds, disks, or immobile bags. Multicellular organisms are Organisms consisting of more than one cell, and having Differentiated cells that perform specialized functions They bear little resemblance to modern lifeforms, and their relationship even with the later lifeforms of the Cambrian explosion is difficult to interpret. The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex Animals around, as evidenced by the More than 100 genera have been described, and well known forms include Arkarua, Charnia, Dickinsonia, Ediacaria, Marywadea, Onega, Pteridinium, and Yorgia. A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic Arkarua is a small Precambrian disk-like Fossil with a raised center a number of radial ridges on the rim and a five-pointed central depression marked Charnia is the Genus name given to a Frond -like Precambrian lifeform with segmented ridges branching alternately to the right and left from a Dickinsonia is an iconic fossil of the Ediacaran biota. It (roughly resembles a bilaterally symmetrical ribbed oval Ediacaria is a Fossil Genus dating to the Ediacaran Period of the Neoproterozoic Era Marywadea is a Genus of Ediacaran biota shaped like an oval with a central ridge Onega stepanovi is one of the lesser known fossil taxa from the Ediacaran Period described by Mikhail A Pteridinium is a Fossil found in a number of Precambrian deposits worldwide Yorgia waggoneri Ivantsov 1999is a member of the Ediacara biota, and resembles the organisms Dickinsonia and Spriggina.
See also
- List of fossil sites (with link directory)
References
- ^ Waggoner, Ben (1998). This is a worldwide list of important and/or well-known localities where Fossils have been found "Interpreting the Earliest Metazoan Fossils: What Can We Learn?". Integrative and Comparative Biology 38 (6): 975—982. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. ISSN 1540-7063. An International Standard Serial Number ( ISSN) is a unique eight-digit number used to identify a print or electronic Periodical publication.
- ^ Hofmann, H. J. ; Narbonne, G. M. , Aitken, J. D. (1990). "Ediacaran remains from intertillite beds in northwestern Canada". Geology 18 (12): 1199-1202.
- ^ Knoll, A. H. ; Walter, M. R. , Narbonne, G. M. , Christie-blick, N. (2004). "A new period for the geologic time scale". Science(Washington) 305 (5684): 621–622.
- ^ a b Ogg, J. G. (2004). "Status of Divisions of the International Geologic Time Scale". Lethaia 37 (2): 183–199.
- ^ Hoffmann, K. H. ; Condon, D. J. , Bowring, S. A. , Crowley, J. L. (2004-09-01). "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 462 - Possible start of first Byzantine indiction cycle. "U-Pb zircon date from the Neoproterozoic Ghaub Formation, Namibia: Constraints on Marinoan glaciation". Geology 32 (9): 817–820. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
- ^ Calver, C. R. ; Black, L. P. , Everard, J. L. , Seymour, D. B. (2004-10-01). "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 331 BC - Alexander the Great defeats Darius III of Persia in the Battle of Gaugamela. "U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania". Geology 32 (10): 893–896. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.
External links
- "Geological time gets a new period: Geologists have added a new period to their official calendar of Earth's history—the first in 120 years", BBC, 17 May, 2004.
- Ediacaran Period. GeoWhen Database. Retrieved on January 5, 2006.
- Introduction to the Vendian Period
- Introduction to the Ediacaran Fauna
- transcript - Catalyst (Australian Broadcasting Corporation)
- Mistaken Point Fauna: The Discovery
| Proterozoic eon | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Paleoproterozoic era | Mesoproterozoic era | Neoproterozoic era | |||||||
| Siderian | Rhyacian | Orosirian | Statherian | Calymmian | Ectasian | Stenian | Tonian | Cryogenian | Ediacaran |
Dictionary
Ediacaran
-adjective
- (geology) of a geologic period within the Neoproterozoic era from about 620 to 542 million years ago
-noun
- (geology) the ediacaran period
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