Roadian

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Roadian
273.01 ± 0.14 – 266.9 ± 0.4 Ma
Chronology
Etymology
Name formalityFormal
Usage information
Celestial body Earth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unit Age
Stratigraphic unit Stage
Time span formalityFormal
Lower boundary definition FAD of the Conodont Jinogondolella nanginkensis
Lower boundary GSSP Stratotype Canyon, Guadalupe Mountains, Texas, USA
31°52′36″N104°52′36″W / 31.8767°N 104.8768°W / 31.8767; -104.8768
Lower GSSP ratified2001 [2]
Upper boundary definitionFAD of the Conodont Jinogondolella aserrata
Upper boundary GSSP Guadalupe Pass, Guadalupe Mountains, Texas, USA
31°51′57″N104°49′58″W / 31.8658°N 104.8328°W / 31.8658; -104.8328
Upper GSSP ratified2001 [2]
Hercosestria cribrosa, A reef-forming Roadian brachiopod from the Glass Mountains of Texas. Hercosestria040111.jpg
Hercosestria cribrosa, A reef-forming Roadian brachiopod from the Glass Mountains of Texas.

In the geologic timescale, the Roadian is an age or stage of the Permian. It is the earliest or lower of three subdivisions of the Guadalupian Epoch or Series. The Roadian lasted between 273.01 and 266.9 million years ago (Ma). It was preceded by the Kungurian and followed by the Wordian. [3]

Contents

Stratigraphy

In 1961, the regional timescale used for the southeastern US had the Wordian and Capitanian as subdivisions of the Guadalupian. [4] Efforts to correlate the Permian stratigraphy of the southeastern US with that of Russia led to the conclusion that between the Wordian stage and the Russian Artinskian stage, another stage needed to be introduced. [5] This stage, the Roadian Stage, was established in 1968 and took its name from the Road Canyon Formation in Brewster County, Texas, formerly considered the lower (oldest) part of the Word Formation. [6] The stage was added to the internationally used IUGS timescale in 2001. [7]

The base of the Roadian is defined as the place in the stratigraphic record where fossils of conodont species Jinogondolella nankingensis first appears. The global reference profile for the base (the GSSP) is located in Stratotype Canyon in the Guadalupe Mountains, Texas ( 31°52′36″N104°52′36″W / 31.87667°N 104.87667°W / 31.87667; -104.87667 ). The top of the Roadian (the base of the Wordian Stage) is at the first appearance of fossils of conodont species Jinogondolella aserrata.

Roadian life

Olson’s Extinction, a worldwide loss of terrestrial vertebrate life occurred during the Early Guadalupian (Roadian, Wordian). [8]

Notable formations

Related Research Articles

<span class="mw-page-title-main">Permian</span> Sixth and last period of the Paleozoic Era 299–252 million years ago

The Permian is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia.

The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0.5 – 259.1 ± 0.4 Mya. The series saw the rise of the therapsids, a minor extinction event called Olson's Extinction and a significant mass extinction called the end-Capitanian extinction event. The Guadalupian was previously known as the Middle Permian.

<span class="mw-page-title-main">Cisuralian</span> First series of the Permian

The Cisuralian is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and dates between 298.9 ± 0.15 – 272.3 ± 0.5 Ma.

In the geologic timescale, the Asselian is the earliest geochronologic age or lowermost chronostratigraphic stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Asselian lasted between 298.9 and 293.52 million years ago (Ma). It was preceded by the Gzhelian and followed by the Sakmarian.

The Bashkirian is in the International Commission on Stratigraphy geologic timescale the lowest stage or oldest age of the Pennsylvanian. The Bashkirian age lasted from 323.2 to 315.2 Ma, is preceded by the Serpukhovian and is followed by the Moscovian.

In the geologic timescale, the Capitanian is an age or stage of the Permian. It is also the uppermost or latest of three subdivisions of the Guadalupian Epoch or Series. The Capitanian lasted between 264.28 and 259.51 million years ago. It was preceded by the Wordian and followed by the Wuchiapingian.

In the geologic timescale, the Sakmarian is an age or stage of the Permian period. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and 290.1 million years ago (Ma). It was preceded by the Asselian and followed by the Artinskian.

In the geologic timescale, the Kungurian is an age or stage of the Permian. It is the latest or upper of four subdivisions of the Cisuralian Epoch or Series. The Kungurian lasted between 283.5 and 273.01 million years ago (Ma). It was preceded by the Artinskian and followed by the Roadian.

In the geologic timescale, the Wordian is an age or stage of the Permian. It is the middle of three subdivisions of the Guadalupian Epoch or Series. The Wordian lasted between 266.9 and 264.28 million years ago (Ma). It was preceded by the Roadian and followed by the Capitanian.

<span class="mw-page-title-main">Wuchiapingian</span> Eighth stage of the Permian

In the geologic timescale, the Wuchiapingian or Wujiapingian is an age or stage of the Permian. It is also the lower or earlier of two subdivisions of the Lopingian Epoch or Series. The Wuchiapingian spans the time between 259.51 and 254.14 million years ago (Ma). It was preceded by the Capitanian and followed by the Changhsingian.

<span class="mw-page-title-main">Changhsingian</span>

In the geologic time scale, the Changhsingian or Changxingian is the latest age or uppermost stage of the Permian. It is also the upper or latest of two subdivisions of the Lopingian Epoch or Series. The Changhsingian lasted from 254.14 to 251.9 Ma ago. It is preceded by the Wuchiapingian age/stage and is followed by the Induan age/stage.

<span class="mw-page-title-main">Induan</span> First age of the Early Triassic epoch

The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.9 Ma and 251.2 Ma. The Induan is sometimes divided into the Griesbachian and the Dienerian subages or substages. The Induan is preceded by the Changhsingian and is followed by the Olenekian.

<span class="mw-page-title-main">Gzhelian</span> Seventh and final stage of the Carboniferous

The Gzhelian is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the youngest stage of the Pennsylvanian, the youngest subsystem of the Carboniferous. The Gzhelian lasted from 303.7 to 298.9 Ma. It follows the Kasimovian age/stage and is followed by the Asselian age/stage, the oldest subdivision of the Permian system.

The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to 208.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.

<i>Alierasaurus</i> Extinct genus of synapsids

Alierasaurus is an extinct genus of caseid synapsid that lived during the early Middle Permian (Roadian) in what is now Sardinia. It is represented by a single species, the type species Alierasaurus ronchii. Known from a very large partial skeleton found within the Cala del Vino Formation, Alierasaurus is one of the largest known caseids. It closely resembles Cotylorhynchus, another giant caseid from the San Angelo Formation in Texas. The dimensions of the preserved foot elements and caudal vertebrae suggest an estimated total length of about 6 or 7 m for Alierasaurus. In fact, the only anatomical features that differ between Alierasaurus and Cotylorhynchus are found in the bones of the feet; Alierasaurus has a longer and thinner fourth metatarsal and it has ungual bones at the tips of the toes that are pointed and claw-like rather than flattened as in other caseids. Alierasaurus and Cotylorhynchus both have very wide, barrel-shaped rib cages indicating that they were herbivores that fed primarily on high-fiber plant material.

Mesogondolella is an extinct genus of conodonts.

Jinogondolella is an extinct genus of conodonts.

Streptognathodus is an extinct genus of conodonts from the Late Carboniferous to Early Permian.

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.

The Khuff Formation is a geologic formation in Oman and Saudi Arabia. It preserves fossils dating back to the Permian and early Triassic periods.

References

  1. ↑ "Chart/Time Scale". www.stratigraphy.org. International Commission on Stratigraphy.
  2. 1 2 "GSSP for Roadian Stage". International Commission on Stratigraphy. Retrieved 13 December 2020.
  3. ↑ Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press
  4. ↑ Glenister, B.F. & Furnish, W.M.; 1961: The Permian ammonoids of Australia, Journal of Paleontology 35(4), pp 673–736.
  5. ↑ Nassichuk, W.W.; 1964: Pennsylvanian and Permian rocks in the Parry Islands Group, Canadian Arctic Archipelago, Report of activities, field
  6. ↑ Furnish & Glenister (1968)
  7. ↑ Glenister, B.F.; Wardlaw, B.R.; Lambert, L.L.; Spinosa, C.; Bowring, S.A.; Erwin, D.H.; Menning, M. & Wilde, G.L.; 1999: Proposal of Guadalupian and Component Roadian, Wordian and Capitanian Stages as International Standards for the Middle Permian Series, Permophiles 34: pp 3–11.
  8. ↑ Sahney, S. & Benton, M.J. (2008). "Recovery from the most profound mass extinction of all time". Proceedings of the Royal Society B: Biological Sciences. 275 (1636): 759–65. doi:10.1098/rspb.2007.1370. PMC   2596898 . PMID   18198148.

Literature

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