Integrated stratigraphy of the Oxfordian global stratotype section and point (GSSP) candidate in the Subalpine Basin (SE France) Pierre Pellenard, Dominique Fortwengler, Didier Marchand, Jacques Thierry, Annachiara Bartolini, Slah Boulila, Pierre-Yves Collin, Raymond Enay, Bruno Galbrun, Silvia Gardin, et al. To cite this version: Pierre Pellenard, Dominique Fortwengler, Didier Marchand, Jacques Thierry, Annachiara Bartolini, et al.. Integrated stratigraphy of the Oxfordian global stratotype section and point (GSSP) candidate in the Subalpine Basin (SE France). Volumina Jurassica, Polish Geological Institute, 2014, 12 (1), pp.1-44. hal-01061435 HAL Id: hal-01061435 https://hal.archives-ouvertes.fr/hal-01061435 Submitted on 2 Jun 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution| 4.0 International License Volumina Jurassica, 2014, Xii (1): 1–44 Integrated stratigraphy of the Oxfordian global stratotype section and point (GSSP) candidate in the Subalpine Basin (SE France) Pierre PELLENARD1, Dominique FORTWENGLER1, Didier MARCHAND1, Jacques THIERRY1, Annachiara BARTOLINI2, Slah BOULILA3, Pierre-Yves COLLIN1, Raymond ENAY4, Bruno GALBRUN3, Silvia GARDIN5, Vincent HUAULT6, Emilia HURET7, Mathieu MARTINEZ8, Carmela CHATEAU SMITH9 Key words: Callovian-Oxfordian boundary, biostratigraphy, ammonites, dinoflagellate cysts, calcareous nannofossils, cyclostratigraphy, chemostratigraphy. Abstract. An integrated biostratigraphic approach, based on ammonites, calcareous nannofossils, dinoflagellates, combined with sedi- mentology, carbon-isotope and physical stratigraphy, is proposed for the Subalpine Basin (Thuoux and Saint-Pierre d’argençon sections). Within the expanded marl deposits of the Terres Noires Fm., the Callovian-Oxfordian boundary is particularly well defined by ammonite taxa from different families (i.e. Cardioceratidae, Oppeliidae, Aspidoceratidae and Perisphinctidae), calcareous nannoplankton (first oc- currence of large-sized Stephanolithion bigotii) and dinoflagellate cysts (first occurrence ofWanaea fimbriata). This precise biostratigra- phy and diversity of ammonites permit long-range correlations with Boreal and Pacific domains. The exceptional outcrop conditions and continuous sedimentation allow high-resolution chemostratigraphy and cyclostratigraphy to be used. Variations of the δ13c record (1.5‰ increase during the Lamberti Zone), consistent with data from other sections of the Subalpine Basin and with the Paris Basin, provide ad- ditional markers to characterise the Callovian-Oxfordian boundary. Promising results from cyclostratigraphy should serve to constrain the duration of biostratigraphic units and thus improve the Late Jurassic Geologic Time Scale. Comparisons are made with the two other can- didates for an Oxfordian GSSP, Redcliff Point (UK) and Dubki (Russian Platform). Finally, the advantages of the Subalpine Basin sections support the proposal of Thuoux as a suitable GSSP candidate for the base of the Oxfordian Stage. 1 UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 Bd Gabriel, 21000 Dijon, France; e-mail: [email protected]; corresponding author. 2 Muséum national d’histoire naturelle, uMr cnrS7207 cr2P «Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements», France. 3 Université Paris 6, UMR CNRS7193 ISTeP «Institut des Sciences de la Terre-Paris», Paris, France. 4Université Claude Bernard Lyon 1, Lyon, France. 5 Université Paris 6, UMR CNRS7207 CR2P «Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements», Paris, France. 6 UMR CNRS 7359 Géoressources, Université de Lorraine, BP 239, 54506 Vandœuvre-lès-nancy cedex, France. 7 ANDRA, Parc de la Croix-Blanche, 1-7 rue Jean Monnet, 92298 Châtenay-Malabry, France. 8 UMR CNRS/Total/UPPA 5150, université de Pau-Pays de l’adour, BP 1155, 64013 Pau cedex. 9 UFR SVTE, Université de Bourgogne, 6 Bd Gabriel, 21000 Dijon, France. 2 Pierre Pellenard et al. INTRODUCTION sil macroinvertebrates (e.g. belemnites and brachiopods), several microfossil groups (calcareous nannofossils, dino- flagellates, spores and pollen, foraminifers and ostracods) In Western European basins, the Callovian-Oxfordian provide additional biostratigraphic data. transition is frequently marked by hiatuses or condensed Biostratigraphic, sedimentological and tectonic aspects levels. The scarcity of available ammonite-rich continuous of the Middle-Late Jurassic transition have been studied, sedimentary successions, which would allow precise ammo- over several decades, in numerous well-exposed outcrops in nite biostratigraphy and integration of ammonite taxa from the Diois, Baronnies and the Buëch Valley (Artru, 1972; Tri- various palaeobiogeographic provinces, renders difficult the bovillard, 1989; Dardeau et al., 1994; Graciansky et al., choice of a reliable section to define a Global boundary Stra- 1999; Fortwengler, Marchand, 1994a–d; Fortwengler et al., totype Section and Point (GSSP) for the Middle-Late Juras- 1997; Pellenard, 2003). In many sections of this domain, sic transition. Among the possibilities are 1) the Subalpine abundant, characteristic, well-preserved ammonites provide Basin (SE France), where the Callovian-Oxfordian bound- an accurate biostratigraphy. The Callovian-Oxfordian ary is well identified and characterised in the expanded boundary is especially well exposed at the Thuoux and Terres Noires Formation (Fortwengler et al., 1997), and 2) Saint-Pierre d’Argençon sections, where all ammonite- bio the Oxford Clay Formation in Dorset (England), where horizons and subzones of the uppermost Callovian Lamberti more condensed sections show all the biohorizons bracket- and basal Oxfordian Mariae zones can be clearly identified ing the boundary (Page, 2004). In this context, the Savourn- (Fortwengler et al., 2012). New investigations were recently on and Thuoux sections in the Subalpine Basin were pro- performed on these sections, across the Callovian-Oxfordian posed some years ago as potential candidates for the boundary, with precise facies analyses, nannofossil and di - callovian–oxfordian GSSP, as the result of several meet- noflagellate/palynomorph determination, clay mineralogy, ings organised from 1993 in the Subalpine Basin, by the geophysical measurements (i.e. field gamma-ray spectrome- groupe Français d’Étude du Jurassique (gFeJ), the Oxford- try and magnetic susceptibility) and geochemical analyses ian Working Group (OWG) and the International Subcom- (Pellenard, Deconinck, 2006; Courtinat, 2006; Boulila et al., mission on Jurassic Stratigraphy (ISJS; Enay, Meléndez, 2008, 2010; Giraud et al., 2009; Pellenard et al., 2014c). 1984; Atrops et al., 1993; Atrops, Meléndez, 1994). Never- Here we summarise and integrate the recently ob- theless, since then, no official decision about the Oxfordian tained stratigraphic information for both the Thuoux and GSSP has been taken (Meléndez, 2003; 2004). The Redcliff Saint-Pierre d’argençon sections, and support the propos- Point/Ham Cliff section in Dorset (UK) was first proposed al that the first of them be the GSSP for the base of the as an alternative (Page et al., 2009a, b) and, more recently, Oxfordian stage. a new section on the Russian Platform at Dubki has also been proposed as a potential candidate (Kiselev et al., 2013). Here, we present recent palaeontological and other strati - GEOGRAPHIC AND GEOLOGICAL SETTINGS graphic investigations at Thuoux in the Subalpine Basin, to propose this section as a candidate for the Oxfordian GSSP, During the Jurassic, the Subalpine Basin (SE France) with complementary information from a nearby section at formed part of the External Alpine Realm or Dauphinois Saint-Pierre d’Argençon, in confirmation of the initial stud- Realm (Baudrimont, Dubois, 1977; Dubois, Delfaud, 1989). ies (Fortwengler, Marchand, 1994a–d; Fortwengler et al., Four areas, defined geographically and tectonically, can be 1997; Fortwengler et al., 2012; Fortwengler et al., 2013; recognised within this basin (Fig. 1): 1) the Vivaro-Cevenol Pellenard, 2013; Pellenard et al., 2014b). Platform, to the south of the French Massif Central, is the The Subalpine Basin is part of the Submediterranean maximum western extent of the Subalpine Basin; 2) the Pro- palaeobiogeographic province. The Terres Noires Fm. is vençal Platform, including the Digne and Castellane arcs, bio stratigraphically subdivided, using the ammonite zonal is on the south-eastern margin; 3) the Subalpine Range, in- scheme established for this faunal province (Thierry et al., cluding the Chartreuse and Vercors ranges, lies to the north; 1997; Cariou et al., 1997). However, the ammonite associa- 4) the Diois, the Baronnies and the Buëch Valley form tions are also rich in cardioceratids, characteristic of the the central part of the Subalpine Basin. Subboreal Province (Marchand et al., 1990). Both zonal From the Late Bajocian to the Middle Oxfordian, the schemes are thus applicable, enhancing the correlations be- Subalpine Basin was strongly subsident, opening