Base of the Toarcian Stage of the Lower Jurassic defined by the Global Boundary Stratotype Section and Point (GSSP) at the Peniche section (Portugal)

Rogério Bordalo da Rocha; Emanuela Mattioli; Luís Vítor Duarte; Bernard Pittet; Serge Elmi; René Mouterde; Maria Cristina Cabral; Maria José Comas-Rengifo; Juan José Gómez; António Goy; Stephen P. Hesselbo; Hugh C. Jenkyns; Kate Littler; Samuel Mailliot; Luiz Carlos Veiga de Oliveira; Maria Luisa Osete; Nicola Perilli; Susana Pinto; Christiane Ruget; Guillaume Suan

doi:10.18814/epiiugs/2016/v39i3/99741

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Episodes 2016; 39(3): 460-481

Published online September 1, 2016

https://doi.org/10.18814/epiiugs/2016/v39i3/99741

Base of the Toarcian Stage of the Lower Jurassic defined by the Global Boundary Stratotype Section and Point (GSSP) at the Peniche section (Portugal)

Rogério Bordalo da Rocha¹, Emanuela Mattioli², Luís Vítor Duarte³, Bernard Pittet², Serge Elmi^2†, René Mouterde^4†, Maria Cristina Cabral⁵, Maria José Comas-Rengifo⁶, Juan José Gómez⁷, António Goy⁶, Stephen P. Hesselbo⁸, Hugh C. Jenkyns⁹, Kate Littler⁸, Samuel Mailliot^2a, Luiz Carlos Veiga de Oliveira¹⁰, Maria Luisa Osete¹¹, Nicola Perilli¹², Susana Pinto¹³, Christiane Ruget¹⁴, Guillaume Suan²

¹GeoBioTec and Earth Sciences Department, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica (Portugal); Toarcian Task Group Convenor. E-mail: rbr@fct.unl.pt
²Univ Lyon, Université Claude Bernard Lyon 1, Ens de Lyon, CNRS, UMR 5276 LGL-TPE, F-69622, Villeurbanne, France. E-mail: emanuela.mattioli@univ-lyon1.fr, Toarcian Task Group Secretary; bernard.pittet@univ-lyon1.fr; guillaume.suan@univ-lyon1.fr
^2aPresent address: Observatoire de Lyon, Université Lyon 1, Campus de la Doua, Bâtiment Geode, 69622 Villeurbanne Cedex (France). E-mail: samuel.mailliot@univ-lyon1.fr
^2†Former Toarcian Working Group Convenor.
³MARE - University of Coimbra, Earth Sciences Department, Rua Silvio Lima, Polo II, Coimbra (Portugal). l E-mail: duarte@dct.uc.pt
^4†Université Catholique de Lyon, France.
⁵Universidade de Lisboa, Faculdade de Ciências, Departamento de Geologia e Instituto Dom Luiz (IDL), Campo Grande, C6-40, 1749-016 Lisboa (Portugal). E-mail: mccabral@fc.ul.pt
⁶Departamento de Paleontologia, Facultad de Ciencias Geológicas, Univ. Complutense de Madrid. José António Novais, 2, 28040 Madrid (Spain). E-mail: mjcomas@ucm.es; angoy@geo.ucm.es
⁷Departamento de Estratigrafía, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid e IGEO (CSIC-UCM), José Antonio Novais 2, 28040 Madrid, España. E-mail: jgomez@ucm.es
⁸Camborne School of Mines, University of Exeter (United Kingdom). E-mail: S.P.Hesselbo@exeter.ac.uk; K.Littler@exeter.ac.uk
⁹Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN (United Kingdom). E-mail: hughj@earth.ox.ac.uk
¹⁰Petrobras University, Rua Ulisses Guimarães 565, 80 andar, 20211-225, Rio de Janeiro (Brazil). E-mail: lcveiga@petrobras.com.brlcveiga@petrobras.com.br
¹¹Departamento de Física de la Tierra, Facultad de Ciencias Físicas, Avenida Complutense s/n, Universidad Complutense de Madrid and Instituto de Geociencias, IGEO, CSIC, 28040 Madrid (Spain). E-mail: mlosete@fis.ucm.es
¹²Dipartimento Scienze della Terra, Università degli Studi di Pisa, Via S. Maria 53, 56100 Pisa (Italy). E-mail: nicola.perilli@unipi.it
¹³Universidade de Lisboa, Faculdade de Ciências, Departamento de Geologia, Campo Grande, C6-40, 1749-016 Lisboa (Portugal). E-mail: susanapvpinto@gmail.com
¹⁴Chipier, Route de Pimotin, 69420 Tupin et Semons (France). E-mail: andrechris.ruget@gmail.com

Received: July 10, 2015; Accepted: February 18, 2016

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Global Stratotype Section and Point (GSSP) for the base of Toarcian Stage, Lower Jurassic, is placed at the base of micritic limestone bed 15e at Ponta do Trovão (Peniche, Lusitanian Basin, Portugal; coordinates: 39°22’15’’N, 9°23’07’’W), 80km north of Lisbon, and coincides with the mass occurrence of the ammonite Dactylioceras (Eodactylites). The Pliensbachian/ Toarcian boundary (PLB/TOA) is contained in a continuous section forming over 450m of carbonate-rich sediments. Tectonics, syn-sedimentary disturbance, metamorphism or significant diagenesis do not significantly affect this area. At the PLB/TOA, no vertical facies changes, stratigraphical gaps or hiatuses have been recorded. The base of the Toarcian Stage is marked in the bed 15e by the first occurrence of D. (E.) simplex, co-occurring with D. (E.) pseudocommune and D. (E.) polymorphum. The ammonite association of D. (Eodactylites) ssp. and other species e.g. Protogrammoceras (Paltarpites) cf. paltum, Lioceratoides aff. ballinense and Tiltoniceras aff. capillatum is particularly significant for the boundary definition and correlation with sections in different basins. Ammonites of the PLB/ TOA are taxa characteristic of both the Mediterranean and Northwest European provinces that allow reliable, global correlations. The PLB/TOA is also characterized by other biostratigraphical markers (brachiopods, calcareous nannofossils, ostracods and benthic foraminifers) and by high-resolution stable carbon and oxygen isotopes, and ⁸⁷Sr/⁸⁶Sr ratios that show distinctive changes just above the PLB/TOA, thus providing additional, powerful tools for global correlations. The PBL-TOA lies at the end of a second (and third) order cycle of sea-level change, and the top of bed 15e is interpreted as a sequence boundary. Cyclostratigraphy analysis is available for the Lower Toarcian of Ponta do Trovão. Detailed correlations with the Almonacid de la Cuba section (Iberian Range, Spain) provide complementary data of the ammonite succession in the Northwest European Hawskerense and Paltum Subzones, and magnetostratigraphical data that allow supraregional correlations. The proposal was voted on by the Toarcian Working Group in June, 2012, and by the International Subcommission on Jurassic Stratigraphy in September, 2012, approved by the ICS in November, 2014, and ratified by the IUGS in December, 2014. With this Toarcian GSSP, all international stages of the Lower Jurassic have been officially defined.