Toarcian

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Toarcian
184.2 ± 0.3 – 174.7 ± 0.8 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 Peniche, Portugal
Lower boundary GSSP FAD of the Ammonite D. (E.) simplex
39°22′15″N9°23′07″W / 39.3708°N 9.3853°W / 39.3708; -9.3853
Lower GSSP ratified2014 [2]
Upper boundary definitionFAD of the Ammonites Leioceras opalinum and Leioceras lineatum
Upper boundary GSSP Fuentelsaz, Spain
41°10′15″N1°50′00″W / 41.1708°N 1.8333°W / 41.1708; -1.8333
Upper GSSP ratified2000 [3]

The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.7 ±0.8 Ma. [4] It follows the Pliensbachian and is followed by the Aalenian. [5]

Contents

The Toarcian Age began with the Toarcian Oceanic Anoxic Event, a major anoxic event associated with marine extinctions and increased global temperatures that sets its fossil faunas apart from the previous Pliensbachian age. It is believed to have ended with a global cooling event known as the Comptum Cooling Event, although whether it represented a worldwide event is controversial. [6]

Stratigraphic definitions

The Toarcian takes its name from the city of Thouars, just south of Saumur in the Loire Valley of France. The stage was introduced by French palaeontologist Alcide d'Orbigny in 1842, after examining rock strata of this age in a quarry near Thouars.

In Europe this period is represented by the upper part of the Lias.

The base of the Toarcian is defined as the place in the stratigraphic record where the ammonite genus Eodactylites first appears. A global reference profile (a GSSP) for the base is located at Peniche, Portugal. The top of the stage is at the first appearance of ammonite genus Leioceras .

In the Tethys domain, the Toarcian contains the following ammonite biozones:

Related Research Articles

The Early Jurassic Epoch is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic–Jurassic extinction event, 201.3 Ma, and ends at the start of the Middle Jurassic 174.7 ±0.8 Ma.

<span class="mw-page-title-main">Aalenian</span> First age of the Middle Jurassic

The Aalenian is a subdivision of the Middle Jurassic Epoch/Series of the geologic timescale that extends from about 174.7 ±0.8 Ma to about 170.9 ±0.8 Ma. It was preceded by the Toarcian and succeeded by the Bajocian.

<span class="mw-page-title-main">Middle Jurassic</span> Second part of the Jurassic geological period, from 174 to 163 million years ago

The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland, the Calcaire de Caen of France, the Daohugou Beds in China, the Itat Formation in Russia, the Tiouraren Formation of Niger, and the Isalo III Formation of western Madagascar.

The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma. The Albian is preceded by the Aptian and followed by the Cenomanian.

<span class="mw-page-title-main">Anisian</span> Stage of the Triassic

In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 247.2 million years ago until 242 million years ago. The Anisian Age succeeds the Olenekian Age and precedes the Ladinian Age.

In the geologic timescale, the Bajocian is an age and stage in the Middle Jurassic. It lasted from approximately 170.9 ±0.8 Ma to around 168.2 ±1.2 Ma. The Bajocian Age succeeds the Aalenian Age and precedes the Bathonian Age.

In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.2 ±1.2 Ma to around 165.3 ±1.1 Ma. The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age.

In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.6 ± 2.0 Ma. The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceous and precedes the Hauterivian Stage of the Lower Cretaceous.

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.

The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77. The Hauterivian is preceded by the Valanginian and succeeded by the Barremian.

The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding age. Both age and stage bear the same name.

<span class="mw-page-title-main">Turonian</span> Second age of the Late Cretaceous epoch

The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma. The Turonian is preceded by the Cenomanian Stage and underlies the Coniacian Stage.

The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma. The Coniacian is preceded by the Turonian and followed by the Santonian.

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 Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma. The Hettangian follows the Rhaetian and is followed by the Sinemurian.

<span class="mw-page-title-main">Sinemurian</span> Second age of the Early Jurassic

In the geologic timescale, the Sinemurian is an age and stage in the Early or Lower Jurassic Epoch or Series. It spans the time between 199.5 ±0.3 Ma and 192.9 ±0.3 Ma. The Sinemurian is preceded by the Hettangian and is followed by the Pliensbachian.

The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 192.9 ±0.3 Ma and 184.2 ±0.3 Ma. The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian.

In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 154.8 ±0.8 Ma and 149.2 ±0.7 Ma. The Kimmeridgian follows the Oxfordian and precedes the Tithonian.

<span class="mw-page-title-main">Ladinian</span> Age in the Middle Triassic

The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between 242 Ma and ~237 Ma. The Ladinian was preceded by the Anisian and succeeded by the Carnian.

References

  1. "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy.
  2. da Rocha, Rogério Bordalo; Mattioli, Emanuela; Duarte, Luís Vítor; Pittet, Bernard; Elmi, Serge; Mouterde, René; Cabral, Maria Cristina; Comas-Rengifo, Maria José; Gómez, Juan José; Goy, António; Hesselbo, Stephen P.; Jenkyns, Hugh C.; Littler, Kate; Mailliot, Samuel; Veiga de Oliveira, Luiz Carlos; Osete, Maria Luisa; Nicola, Perilli; Pinto, Susana; Ruget, Christiane; Suan, Guillaume (September 2016). "Base of the Toarcian Stage of the Lower Jurassic defined by the Global Boundary Stratotype Section and Point (GSSP) at the Peniche section (Portugal)". Episodes. 39 (3): 460–481. doi: 10.18814/epiiugs/2016/v39i3/99741 .
  3. Cresta, S.; Goy, A.; Arias, C.; Barrón, E.; Bernad, J.; Canales, M.; García-Joral, F.; García-Romero, E; Gialanella, P.; Gómez, J.; González, J.; Herrero, C.; Martínez2, G.; Osete, M.; Perilli, N.; Villalaín, J. (September 2001). "The Global Boundary Stratotype Section and Point (GSSP) of the Toarcian-Aalenian Boundary (Lower-Middle Jurassic)" (PDF). Episodes. 24 (3): 166–175. doi:10.18814/epiiugs/2001/v24i3/003 . Retrieved 13 December 2020.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  4. Benton, Michael J. (2012). Prehistoric Life. Edinburgh, Scotland: Dorling Kindersley. pp. 44–45. ISBN   978-0-7566-9910-9.
  5. For a detailed geologic timescale see Gradstein et al. (2004)
  6. Henriques, Maria Helena Paiva; Canales, Maria Luisa (September–October 2013). "Ammonite-benthic Foraminifera turnovers across the Lower-Middle Jurassic transition in the Lusitanian Basin (Portugal)". Geobios . 46 (5): 395–408. Bibcode:2013Geobi..46..395H. doi:10.1016/j.geobios.2013.06.002. hdl: 10316/27258 . Retrieved 23 November 2022.

Sources