Stephanian (stage)

Last updated
System Series
(NW Europe)
Stage
(NW Europe)
Series
(ICS)
Stage
(ICS)
Age
(Ma)
Permian younger
Carboniferous Silesian Stephanian Pennsylvanian Gzhelian 298.9–303.7
Kasimovian 303.7–307.0
Westphalian Moscovian 307.0–315.2
Bashkirian 315.2–323.2
Namurian
Mississippian Serpukhovian 323.2–330.9
Dinantian Visean Visean 330.9–346.7
Tournaisian Tournaisian 346.7–358.9
Devonian older
Subdivisions of the Carboniferous system in Europe compared with the official ICS-stages (as of 2018)

The Stephanian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 307.5 [1] and 299 Ma (million years ago). It is a subdivision of the Carboniferous system or period and the regional Silesian series. The uppermost units of the Coal Measures of England and Wales are probably of Stephanian age, though the larger part of this formation is referred to the earlier Westphalian. The stage derives its name from the city of Saint-Étienne for its coal mining basin in eastern central France (which itself derives from associations with Saint Stephen) where strata of this age occur. [2]

Contents

In the official geologic timescale of the ICS, the Stephanian is placed within the Pennsylvanian epoch (323-299 Ma). [3]

The (regionally defined) Stephanian stage corresponds to the (internationally used) Kasimovian and Gzhelian stages. [1] References appear in scientific literature to a Stephanian epoch or Stephanian series reflecting the stage's earlier status. Sediments younger than the Stephanian are sometimes termed the Autunian, a regional stage which includes the Carboniferous-Permian boundary. [4] [5]

Stratigraphy

From youngest to oldest, the proposed substages of the Stephanian are: [4] [5]

Base of the Stephanian

The Westphalian-Stephanian boundary is controversial and has not been formally defined. The early part of the Stephanian is difficult to recognize in much of Europe, due to sediment hiatuses or a transition from coal to unfossiliferous red beds. This issue is most apparent in the Lorraine-Saar-Nahe Basin of France and Germany, where a long hiatus occupies several million years between the Westphalian D and Stephanian A substages. [1]

Several workarounds have been proposed, but many bring forward their own problems. Many sources air on the side of caution and position the start of the Stephanian at the end of the hiatus. By that time, Kasimovian-type plant species are well-established, suggesting that part of the Westphalian D is Kasimovian in age. Other studies disagree with this approach, instead defining the Westphalian-Stephanian boundary at a major transition of plant faunas prior to the hiatus. [1]

Northwest Spain seems to offer a potential solution to the debate, since the regions of Asturias and Cantabria offer undisrupted and fossil-rich sediments which appear to fill in the gap between Westphalian D and Stephanian A. Most Carboniferous stratigraphers accept the utility of this interval, which has been named as the "Cantabrian" substage, the earliest substage of the Stephanian. Kasimovian-type plants first appear just above the base of the Cantabrian, arguing that the base of the Stephanian is slightly older than the start of the Kasimovian (around 307 Ma). [1]

Related Research Articles

<span class="mw-page-title-main">Carboniferous</span> Fifth period of the Paleozoic Era, 359–299 million years ago

The Carboniferous is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period 358.9 million years ago (mya), to the beginning of the Permian Period, 298.9 mya. The name Carboniferous means "coal-bearing", from the Latin carbō ("coal") and ferō, and refers to the many coal beds formed globally during that time.

The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly 323.2 million years ago to 298.9 million years ago. As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-producing beds of this age are widespread.

Tertiary is an obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start of the Cenozoic Era, and extended to the beginning of the Quaternary glaciation at the end of the Pliocene Epoch. The time span covered by the Tertiary has no exact equivalent in the current geologic time system, but it is essentially the merged Paleogene and Neogene periods, which are informally called the Early Tertiary and the Late Tertiary, respectively.

<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.

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 Callovian is an age and stage in the Middle Jurassic, lasting between 165.3 ± 1.1 Ma and 161.5 ± 1.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian.

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

The Carnian is the lowermost stage of the Upper Triassic Series. It lasted from 237 to 227 million years ago (Ma). The Carnian is preceded by the Ladinian and is followed by the Norian. Its boundaries are not characterized by major extinctions or biotic turnovers, but a climatic event occurred during the Carnian and seems to be associated with important extinctions or biotic radiations. Another extinction occurred at the Carnian-Norian boundary, ending the Carnian age.

The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya and 83.6 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.

The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used by the International Commission on Stratigraphy, estimated that it lasted from 372.2 million years ago to 358.9 million years ago. It was preceded by the Frasnian stage and followed by the Tournaisian stage.

<span class="mw-page-title-main">Tournaisian</span> First stage of the Carboniferous

The Tournaisian is in the ICS geologic timescale the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. The Tournaisian age lasted from 358.9 Ma to 346.7 Ma. It is preceded by the Famennian and is followed by the Viséan. In global stratigraphy, the Tournaisian contains two substages: the Hastarian and Ivorian. These two substages were originally designated as European regional stages.

<span class="mw-page-title-main">Viséan</span> Second stage of the Carboniferous

The Visean, Viséan or Visian is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the second stage of the Mississippian, the lower subsystem of the Carboniferous. The Visean lasted from 346.7 to 330.9 Ma. It follows the Tournaisian age/stage and is followed by the Serpukhovian age/stage.

<span class="mw-page-title-main">Serpukhovian</span> Third stage of the Carboniferous

The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from 330.9 Ma to 323.2 Ma. It is preceded by the Visean and is followed by the Bashkirian. The Serpukhovian correlates with the lower part of the Namurian Stage of European stratigraphy and the middle and upper parts of the Chesterian Stage of North American stratigraphy.

The Kasimovian is a geochronologic age or chronostratigraphic stage in the ICS geologic timescale. It is the third stage in the Pennsylvanian, lasting from 307 to 303.7 Ma. The Kasimovian Stage follows the Moscovian and is followed by the Gzhelian. The Kasimovian saw an extinction event which occurred around 305 mya, referred to as the Carboniferous Rainforest Collapse. It roughly corresponds to the Missourian in North American geochronology and the Stephanian in western European geochronology.

<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.

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

The Allegheny Group, often termed the Allegheny Formation, is a Pennsylvanian-age geological unit in the Appalachian Plateau. It is a major coal-bearing unit in the eastern United States, extending through western and central Pennsylvania, western Maryland and West Virginia, and southeastern Ohio. Fossils of fishes such as Bandringa are known from the Kittaning Formation, which is part of the Allegheny Group.

The Moscovian is in the ICS geologic timescale a stage or age in the Pennsylvanian, the youngest subsystem of the Carboniferous. The Moscovian age lasted from 315.2 to 307 Ma, is preceded by the Bashkirian and is followed by the Kasimovian. The Moscovian overlaps with the European regional Westphalian stage and the North American Atokan and Desmoinesian stages.

The Namurian is a stage in the regional stratigraphy of northwest Europe, with an age between roughly 331 and 319 Ma. It is a subdivision of the Carboniferous system or period, as well as the regional Silesian series. The Namurian is named for the Belgian city and province of Namur where strata of this age occur. The Millstone Grit Group in the lithostratigraphy of northern England and parts of Wales is also of Namurian age.

The Westphalian is a stage or age in the regional stratigraphy of northwest Europe, with an age between roughly 319 and 307.5 Ma. It is a subdivision of the Carboniferous system or period and the regional Silesian series. The Westphalian is named for the region of Westphalia in western Germany where strata of this age occur. The Coal Measures of England and Wales are also largely of Westphalian age, though they also extend into the succeeding Stephanian.

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

In lithostratigraphy, coal measures are coal-bearing strata, with the term typically applied to European units of the Upper Carboniferous System.

The Scottish Coal Measures Group is a lithostratigraphic unit referring to the coal-bearing succession of rock strata which occur in Scotland during the Westphalian regional stage of the Carboniferous Period. It is the Scottish portion of the informal Coal Measures Group, which also includes the South Wales and Pennine coal measures. The Scottish coal measures are well-exposed across the Midland Valley. The group is also found within small grabens in the vicinity of Sanquhar and Thornhill.

References

  1. 1 2 3 4 5 Knight, John A.; Cleal, Christopher J.; Álvarez-Vázquez, Carmen (2023-06-14). "The challenge of relating the Kasimovian to west European chronostratigraphy: a critical review of the Cantabrian and Barruelian substages of the Stephanian Stage". Geological Society, London, Special Publications. 535 (1): 31–71. doi: 10.1144/SP535-2022-189 . ISSN   0305-8719.
  2. "Archived copy" (PDF). Archived from the original (PDF) on 2011-03-04. Retrieved 2016-04-08.{{cite web}}: CS1 maint: archived copy as title (link)
  3. Aretz, M.; Herbig, H.G.; Wang, X.D.; Gradstein, F.M.; Agterberg, F.P.; Ogg, J.G. (2020), "The Carboniferous Period", Geologic Time Scale 2020, Elsevier, pp. 811–874, doi:10.1016/b978-0-12-824360-2.00023-1, ISBN   978-0-12-824360-2 , retrieved 2023-10-09
  4. 1 2 Waters, C.N. (2011-07-13), Waters, C.N.; Somerville, I.D.; Jones, N.S.; Cleal, C.J. (eds.), "Definitions of chronostratigraphic subdivisions: geochronology and event stratigraphy", A Revised Correlation of Carboniferous Rocks in the British Isles (First ed.), The Geological Society of London, pp. 3–10, doi:10.1144/sr26.2, ISBN   978-1-86239-694-4
  5. 1 2 Aretz, M.; Herbig, H.G.; Wang, X.D.; Gradstein, F.M.; Agterberg, F.P.; Ogg, J.G. (2020), "The Carboniferous Period", Geologic Time Scale 2020, Elsevier, pp. 811–874, doi:10.1016/b978-0-12-824360-2.00023-1, ISBN   978-0-12-824360-2