Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes, SW France)

Abstract

Definition of a multi-criteria boundary; stratigraphy of the Campanian-Maastrichtian interval of the geological site at Tercis (Landes, SW France). Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77-70 Ma old series bracketing the Campanian-Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro-and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409-414.  2002 Académie des sciences / Éditions scientifiques et médicales Elsevier SAS lithostratigraphy / chemostratigraphy / magnetostratigraphy / biostratigraphy / geochronology / Campanian / Maastrichtian / stratotype / FranceRésumé -Une limite multicritère a été définie à partir des travaux d'analyse de 70 experts. Ils ont caractérisé la lithostratigraphie, la physicochimie, la biostratigraphie et la géochronologie de l'intervalle 77-70 Ma renfermant la limite Campanien-Maastrichtien. Des corrélations directes ont été établies pour la première fois entre macrofossiles et microfossiles, ainsi que des corrélations directes et indirectes entre outils physico-chimiques et biostratigraphiques. L'incertitude liée à ces relations, le principe de combinaison de plusieurs critères pour fixer le niveau de la limite et des estimations de durée ont été considérés ; de nouvelles unités chronostratigraphiques sont proposées. Le site géologique de Tercis est reconnu par la Commission de Stratigraphie comme la référence internationale pour la stratigraphie de l'intervalle examiné.

Planktonic foraminiferal biostratigraphy and quantitative analysis during the Campanian-Maastrichtian transition at the Oued Necham section (Kalâat Senan, central Tunisia)

“…Gl. calibrated by Husson et al (2011) to an age between -72.34 and -72.75 Ma integrated within the C32n2n Chron, in agreement with Lewy and Odin (2001), Odin and Lamaurelle (2001), Arz and Molina (2002), Odin (2002), Gardin et al (2012), Cohen et al (2013), and Batenburg et al (2014). However, Thibault et al (2012Thibault et al ( , 2015 recognised a slightly younger age of -72.15 ± 0.5 Ma for the boundary.…”

“…Accordingly, henceforth the Radotruncana calcarata HO corresponds to the mid-Campanian, as it occurs much earlier than the LO of Pachydiscus neubergicus (Odin, 2001(Odin, , 2002Ogg and Ogg, 2004). Indeed, newly identified bioevents document a younger absolute age for the C/M boundary (Odin, 2001(Odin, , 2002Ogg and Ogg, 2004;Gardin et al, 2012;Batenburg et al, 2014;Thibault et al, 2015).…”

“…Referring to the Second International Symposium on Cretaceous Stage Boundaries, Brussels, 1995, the longtime use of the Radotruncana calcarata HO to specify the C/M boundary (Herm, 1962;Bolli, 1966;Postuma, 1971;Van Hinte, 1976;Sigal, 1977;Saïd, 1978;Salaj, 1980;Bellier, 1983;Robaszynski et al, 1984;Caron, 1985;Mancini et al, 1996;Rami et al, 1997;Li and Keller, 1998b;Li et al, 1999) is no longer valid (Figure 7). Accordingly, henceforth the Radotruncana calcarata HO corresponds to the mid-Campanian, as it occurs much earlier than the LO of Pachydiscus neubergicus (Odin, 2001(Odin, , 2002Ogg and Ogg, 2004). Indeed, newly identified bioevents document a younger absolute age for the C/M boundary (Odin, 2001(Odin, , 2002Ogg and Ogg, 2004;Gardin et al, 2012;Batenburg et al, 2014;Thibault et al, 2015).…”

“…During the Second International Symposium on Cretaceous Stage Boundaries in Brussels in 1995, it was formally recommended and accepted that the LO of Rugoglobigerina scotti constitutes one of the reported bioevents to mark the C/M boundary (Arz, 1996;Arz and Molina, 2001;Odin, 2001;Arz and Molina, 2002;Odin, 2002) at its GSSP, the Tercis-les-Bains section (France). The foraminiferal bioevent coincides with the LO of the ammonite species Pachydiscus neubergicus among 11 other identified bioevents defined by ammonites, inoceramids, dinoflagellates, calcareous nannofossils, and planktonic and benthic foraminifera species, respectively (Odin, 2001).…”

Small benthic foraminiferal biostratigraphy and palaeoecology during the Campanian-Maastrichtian transition in north-western Tunisia

“…The Campanian/Maastrichtian (C/M) boundary has long been identified with the last occurrence (LO) of Radotruncana calcarata (Cushman, 1946;Saïd, 1978;Salaj, 1980;Bellier, 1983;Robaszynski et al, 1984;Caron, 1985;Li and Keller, 1998b;Rami, 1998;. However, this datum is questioned because it occurs earlier than the first occurrence (FO) of Pachydiscus neubergicus (ammonite index species used as marker of the C/M boundary); thus, certain works consider that the Radotruncana calcarata datum should indicate a mid-Campanian age instead (Arz and Molina, 2001;Odin, 2001Odin, , 2002Ogg and Ogg, 2004;Robaszynski, 2006;Saïdi and Zaghbib-Turki, 2016). The International Commission on Stratigraphy selected the Tercis-les-Bains section, from south-western France, as the Global Stratotype Section and Point (GSSP) for the C/M boundary, which is defined on the basis of twelve simultaneous bioevents (Odin, 2001).…”