In the geological timescale , the Berriasian is an age / stage of the Early/Lower Cretaceous . It is the oldest subdivision in the entire Cretaceous . It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic ) and precedes the Valanginian .
16-721: The Berriasian Stage was introduced in scientific literature by Henri Coquand in 1869. It is named after the village of Berrias in the Ardèche department of France . The largely non-marine English Purbeck Formation is in part of Berriasian age. The first rocks to be described of this age were the beds of the English Purbeck Formation, named as the Purbeckian by Alexandre Brongniart in 1829 following description by Henry De la Beche , William Buckland , Thomas Webster and William Henry Fitton . The base of
32-607: Is a species that has a stratigraphically problematic and geographically limited distribution. A global reference profile (a GSSP ) for the Berriasian has been under active consideration by the Berriasian Working Group (ISCS) of IUGS since 2010. A range of contender GSSP localities has been studied in detail by the Working Group including localities as far apart as Mexico, Ukraine, Tunisia, Iraq and
48-577: Is defined by the base of the Valanginian, which is fixed at the first appearance of calpionellid species Calpionellites darderi . This is just a little below the first appearance of the ammonite species Thurmanniceras pertransiens . Regional terms used in Russia include "Volgian"(which spans perhaps the latest Kimmeridgian, all the Tithonian and an uncertain amount of the lower Berriasian) and
64-407: Is defined by the base of the Valanginian, which is fixed at the first appearance of calpionellid species Calpionellites darderi . This is just a little below the first appearance of the ammonite species Thurmanniceras pertransiens . Regional terms used in Russia include "Volgian"(which spans perhaps the latest Kimmeridgian, all the Tithonian and an uncertain amount of the lower Berriasian) and
80-665: The Comité des travaux historiques et scientifiques , and from 1871 to 1881, he was a munincipal councillor in Marseille. The mineral " coquandite " commemorates his name; its chemical formula is Sb6O8(SO4)•(H2O). Berriasian In the geological timescale , the Berriasian is an age / stage of the Early/Lower Cretaceous . It is the oldest subdivision in the entire Cretaceous . It has been taken to span
96-719: The Upper Cretaceous stages: Coniacian , Santonian and Campanian (1857). In 1871 he proposed the Berriasian stage of the Lower Cretaceous , named after Berrias , a town in the department of Ardèche . He also conducted geological / paleontological research in Spain , Algeria and Morocco . In 1838 he founded the Muséum d'Aix in Aix-en-Provence. From 1862 to 1870 he was a correspondent member of
112-647: The "Ryazanian" (?upper Berriasian) . Henri Coquand Henri Coquand (1813, in Aix-en-Provence – 1881, in Marseille ) was a French geologist and paleontologist . In 1841 he obtained his doctorate in sciences in Paris , and later served as a professor of geology at the University of Besançon , Poitiers and Marseille . From his geological studies of southwestern France, he introduced
128-579: The Berriasian, which is also the base of the Cretaceous System , has traditionally been placed at the first appearance of fossils of the ammonite species Berriasella jacobi . But this is a species that has a stratigraphically problematic and geographically limited distribution. A global reference profile (a GSSP ) for the Berriasian has been under active consideration by the Berriasian Working Group (ISCS) of IUGS since 2010. A range of contender GSSP localities has been studied in detail by
144-655: The Russian Far East. Several markers have been employed to refine correlations and to work towards defining a base for the Berriasian Stage. These include calcareous microfossils , such as Nannoconus , calpionellids , ammonites , palynological data and magnetostratigraphy , notably magnetozone M19n. The calibration of these markers, especially Nannoconus steinmannii minor , N. kamptneri minor , and Calpionella alpina , within precisely fixed magnetozones give greater precision in trying to identify
160-611: The Working Group including localities as far apart as Mexico, Ukraine, Tunisia, Iraq and the Russian Far East. Several markers have been employed to refine correlations and to work towards defining a base for the Berriasian Stage. These include calcareous microfossils , such as Nannoconus , calpionellids , ammonites , palynological data and magnetostratigraphy , notably magnetozone M19n. The calibration of these markers, especially Nannoconus steinmannii minor , N. kamptneri minor , and Calpionella alpina , within precisely fixed magnetozones give greater precision in trying to identify
176-531: The base of the Alpina Subzone in the middle of magnetozone M19n.2n. This site proposal, of Tré Maroua, was subsequently unsuccessful in a vote of the ISCS (8 votes for and 8 against: 4 not voting); a new working group was formed in 2021. In the western part of the ocean of Tethys , the Berriasian consists of four ammonite biozones , from top to bottom (latest to earliest): The top of the Berriasian stage
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#1732765704005192-415: The base of the Alpina Subzone in the middle of magnetozone M19n.2n. This site proposal, of Tré Maroua, was subsequently unsuccessful in a vote of the ISCS (8 votes for and 8 against: 4 not voting); a new working group was formed in 2021. In the western part of the ocean of Tethys , the Berriasian consists of four ammonite biozones , from top to bottom (latest to earliest): The top of the Berriasian stage
208-418: The beds of the English Purbeck Formation, named as the Purbeckian by Alexandre Brongniart in 1829 following description by Henry De la Beche , William Buckland , Thomas Webster and William Henry Fitton . The base of the Berriasian, which is also the base of the Cretaceous System , has traditionally been placed at the first appearance of fossils of the ammonite species Berriasella jacobi . But this
224-546: The best position for a boundary. In 2016, the Berriasian Working Group voted to adopt Calpionella alpina as the primary marker for the base of the Berriasian Stage. In 2019, a GSSP for the Berriasian was nominated by a vote of the Berriasian Working Group of the Cretaceous Subcommission (ISCS): it is the profile of Tré Maroua in the Vocontian Basin (Hautes Alpes, France). The GSSP was defined at
240-403: The best position for a boundary. In 2016, the Berriasian Working Group voted to adopt Calpionella alpina as the primary marker for the base of the Berriasian Stage. In 2019, a GSSP for the Berriasian was nominated by a vote of the Berriasian Working Group of the Cretaceous Subcommission (ISCS): it is the profile of Tré Maroua in the Vocontian Basin (Hautes Alpes, France). The GSSP was defined at
256-648: The time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic ) and precedes the Valanginian . The Berriasian Stage was introduced in scientific literature by Henri Coquand in 1869. It is named after the village of Berrias in the Ardèche department of France . The largely non-marine English Purbeck Formation is in part of Berriasian age. The first rocks to be described of this age were
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