Dapingian | |||||||||||
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Chronology | |||||||||||
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Etymology | |||||||||||
Name formality | Formal | ||||||||||
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Celestial body | Earth | ||||||||||
Regional usage | Global (ICS) | ||||||||||
Time scale(s) used | ICS Time Scale | ||||||||||
Definition | |||||||||||
Chronological unit | Age | ||||||||||
Stratigraphic unit | Stage | ||||||||||
Time span formality | Formal | ||||||||||
Lower boundary definition | FAD of the Conodont Baltoniodus triangularis | ||||||||||
Lower boundary GSSP | Huanghuachang section, Huanghuachang, Yichang, China 30°51′38″N110°22′26″E / 30.8605°N 110.3740°E | ||||||||||
Lower GSSP ratified | 2007 [5] | ||||||||||
Upper boundary definition | FAD of the Graptolite Undulograptus austrodentatus | ||||||||||
Upper boundary GSSP | Huangnitang Section, Huangnitang Village, Changshan, Zhejiang, China 28°51′14″N118°29′23″E / 28.8539°N 118.4897°E | ||||||||||
Upper GSSP ratified | 1997 [6] |
The Dapingian is the third stage of the Ordovician system and the first stage of the Middle Ordovician series. It is preceded by the Floian and succeeded by the Darriwilian. The base of the Dapingian (and the top of the Floian) is defined as the first appearance of the conodont species Baltoniodus triangularis which happened about 470 million years ago. The Dapingian lasted for about 2.7 million years until about 467.3 million years ago. [7]
The Ordovician was divided into three series and six global stages in 1995. Although at the time of 2005 GSSPs for the overlying Darriwilian and underlying "second stage" had already been ratified, definition of a GSSP for the first stage of the Middle Ordovician Series caused difficulties due to the deficiencies of the selected biohorizon and section. [8] The Dapingian was the last Ordovician stage to be ratified, and was initially referred to as an informal and unnamed "third stage" corresponding to the early part of the Middle Ordovician. [9] This third stage was meant to represent the appearance of several major index fossils. The conodont Baltoniodus triangularis, a species found in Baltica and China, defined the base of the regional Baltoscandian Volkhov stage. Another conodont, Tripodus laevis , defined the base of the Whiterockian stage in western North America. T. laevis was also roughly correlated with the appearance of the graptolite Isograptus v. lunatus . [10]
The Whiterock Narrows section in the Ninemile Formation of Nevada was the initial suggestion for the GSSP of the third stage, but a 2001 review of the site revealed that its local conodont fauna was misaligned with wider graptolite zonation. In its place, two formal GSSP candidates were proposed. [11] The Niquivil section of Argentina used another widespread species, Protoprioniodus (Cooperignathus) aranda, as a proxy for B. triangularis, T. laevis, and graptolites, which were absent from the section. [12] The Huanghuachang section of China hosted a more diverse fauna of index fossils, including Baltoniodus triangularis and biostratigraphically useful graptolites and chitinozoans. [10] The Huanghuachang section was approved as the GSSP for the third stage in 2006, and was ratified by the ICS in 2007. [11] [9]
The Dapingian is named after Daping, a village that lies near the Dapingian GSSP at Huanghuachang. The Chenjiahe section, an outcrop with similar rocks, can be found 5 km to the north of the Huanghuachang section. [11] The name of the Dapingian stage was introduced in June 2007 and approved alongside the stage's ratification, beating out earlier suggestions such as "Volkhovian" and "Huanghuachangian". [9]
The Global Boundary Stratotype Section and Point (GSSP) of the Dapingian is the Huanghuachang section ( 30°51′38″N110°22′26″E / 30.8605°N 110.3740°E ), in Huanghuachang, Yichang, China. It is an outcrop of the Dawan Formation. The lower boundary is defined as the first appearance of the conodont species Baltoniodus triangularis in the type section. Radiometric dating has constrained the Floian-Dapingian boundary at 470 million years ago. [7] The exact boundary lies 10.57 m above the base of Dawan Formation. [10] [11]
The Dapingian overlaps with the upper part of the Arenig, a geologic stage used in England. [13] [14] It is also equivalent to the lower part of the North American Whiterockian stage, [15] most of the Baltic/Russian Volkhov stage, [16] [17] and the Castlemainian and Yapeenian stages which have been used in Australia. [13] In Baltoscandia, especially in the East Baltic, the global stage boundary corresponds to the bases of the Megistaspis polyphemus Trilobite Zone and probably Isograptus victoriae victoriae Graptolite Zone. [18]
At the beginning of the Dapingian, there was a drop in sea level of 70–80 m, which is reflected in the rocks as a well-developed hardground surface in Baltoscandia. Changes in sea level during Dapingian age appear to be associated with short pulses of cooling, which have become a harbinger of much colder climate in the next Darriwilian age. [19] At the end of the Dapingian, continental ice was growing with small changes in volume caused by changes in the Earth's orbit. [20]
The Great Ordovician Biodiversification Event (GOBE) lasted in the Dapingian. Fan et al. (2020) define GOBE as a 20 Myr interval that began in the Tremadocian and ended in the late Dapingian, although other researchers have suggested different temporal limits. [21]
The extensive transgression associated with rapid tectonic subsidence, occurred at the end of the Dapingian in the Southern Urals. [22]
The Komstad Regressive Event roughly corresponds to the Dapingian. [23]
Funeralaspis , the oldest named odontopleurine trilobite, was discovered in the Dapingian of the Antelope Valley Formation in Inyo County, California. [24]
Since the Dapingian, there has been a connection between the Afro-European part of Gondwana and Baltica, which is confirmed by the discovery of fossils of cornutan stylophorans Phyllocystis in these regions. [25] Planopora , the oldest сystoporate bryozoan to form erect, bifoliate colonies, is known from the Dapingian of the Baltic paleobasin, Leningrad Oblast, Russia. [26]
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 Ma to the start of the Silurian Period 443.8 Ma.
The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 485.4 ± 1.9 to 470 ± 1.4 million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages.
The Hirnantian is the final internationally recognized stage of the Ordovician Period of the Paleozoic Era. It was of short duration, lasting about 1.4 million years, from 445.2 to 443.8 Ma. The early part of the Hirnantian was characterized by cold temperatures, major glaciation, and a severe drop in sea level. In the latter part of the Hirnantian, temperatures rose, the glaciers melted, and sea level returned to the same or to a slightly higher level than it had been prior to the glaciation.
The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from 485.4 to 477.7 million years ago. The base of the Tremadocian is defined as the first appearance of the conodont species Iapetognathus fluctivagus at the Global Boundary Stratotype Section and Point (GSSP) section on Newfoundland.
The Lopingian is the uppermost series/last epoch of the Permian. It is the last epoch of the Paleozoic. The Lopingian was preceded by the Guadalupian and followed by the Early Triassic.
The Furongian is the fourth and final epoch and series of the Cambrian. It lasted from 497 to 485.4 million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed 10th stage of the Cambrian.
The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species Undulograptus austrodentatus around 467.3 million years ago. It lasted for about 8.9 million years until the beginning of the Sandbian around 458.4 million years ago. This stage of the Ordovician was marked by the beginning of the Andean-Saharan glaciation.
The Diabasbrottet Quarry, located on Mt. Hunneberg, Västergötland, Sweden, is the location of the Global Boundary Stratotype Section and Point (GSSP) which marks the lower boundary of the Floian stage of the Lower Ordovician.
Huangnitang is a village of Zhoutang village, Tianma Subdistrict, Changshan County, Quzhou, Zhejiang Province, China. It is the location of the Global Boundary Stratotype Section and Point (GSSP), which marks the boundary between the Third and Darriwilian Stages of the Middle Ordovician. The GSSP was ratified by the International Union of Geological Sciences in 1997.
The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician series. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from 477.7 to 470 million years ago. The lower boundary is defined as the first appearance of the graptolite species Tetragraptus approximatus.
The Katian is the second stage of the Upper Ordovician. It is preceded by the Sandbian and succeeded by the Hirnantian Stage. The Katian began 453 million years ago and lasted for about 7.8 million years until the beginning of the Hirnantian 445.2 million years ago. During the Katian the climate cooled which started the Late Ordovician glaciation.
The Sandbian is the first stage of the Upper Ordovician. It follows the Darriwilian and is succeeded by the Katian. Its lower boundary is defined as the first appearance datum of the graptolite species Nemagraptus gracilis around 458.4 million years ago. The Sandbian lasted for about 5.4 million years until the beginning of the Katian around 453 million years ago.
The Whiterockian, often referred to simply as the Whiterock, is an earliest or lowermost stage of the Middle Ordovician. Although the Whiterockian or Whiterock Stage refers mainly to the early Middle Ordovician in North America, it is often used in the older literature in a global sense.
The Jiangshanian is the middle stage of the Furongian series. It follows the Paibian Stage and is succeeded by the still unnamed Stage 10 of the Cambrian. The base is defined as the first appearance of the trilobite Agnostotes orientalis which is estimated to be 494 million years ago. The Jiangshanian lasted until approximately 489.5 million years ago.
The Wuliuan stage is the fifth stage of the Cambrian, and the first stage of the Miaolingian Series of the Cambrian. It was formally defined by the International Commission on Stratigraphy in 2018. Its base is defined by the first appearance of the trilobite species Oryctocephalus indicus; it ends with the beginning of the Drumian Stage, marked by the first appearance of the trilobite Ptychagnostus atavus around 504.5 million years ago.
Iapetognathus fluctivagus is a species of denticulate cordylodan conodonts belonging to the genus Iapetognathus. It existed during the Tremadocian Age of the Ordovician. It is an important index fossil in biostratigraphy.
Iapetognathus is a genus of cordylodan conodonts. It is one of the oldest denticulate euconodont genera known.
Conodonts are an extinct class of animals whose feeding apparatuses called teeth or elements are common microfossils found in strata dating from the Stage 10 of the Furongian, the fourth and final series of the Cambrian, to the Rhaetian stage of the Late Triassic. These elements can be used alternatively to or in correlation with other types of fossils in the subfield of the stratigraphy named biostratigraphy.
Baltoniodus is an extinct genus of conodonts.
It has been suggested that the Middle Ordovician meteorite bombardment played a crucial role in the Great Ordovician Biodiversification Event, but this study shows that the two phenomena were unrelated
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