Redefinition of the Ilerdian Stage (early Eocene)
DOI:
https://doi.org/10.1344/105.000000268Keywords:
Ilerdian stage, Silver spike, Larger foraminifera, CIE, P-E boundary, Pyrenees, Tremp-Graus BasinAbstract
The Ilerdian Stage was created by Hottinger and Schaub in 1960 to accommodate a significant phase in the evolution of larger foraminifera not recorded in the northern European basins, and has since been adopted by most researchers working on shallow marine early Paleogene deposits of the Tethys domain. One of the defining criteria of the stage is a major turnover of larger foraminifera, marked by the FO’s of Alveolina vredenburgi (formerly A. cucumiformis) and Nummulites fraasi. There is now conclusive evidence that this turnover was coeval with the onset of the Carbon Isotope Excursion (CIE) and, consequently, with the Paleocene-Eocene (P-E) boundary, a temporal correspondence that reinforces the usefulness of the Ilerdian as a chronostratigraphic subdivision of the early Eocene in a regional context. However, in addition to the paleontological criteria, the definition of the Ilerdian was also based on the designation of two reference sections in the southern Pyrenees: Tremp (stratotype) and Campo (parastratotype). In both sections, the base of the stage was placed at the lowest marine bed containing A. vredenburgi specimens. Using the CIE as a correlation tool we demonstrate that these two marine beds occur at different chronological levels, being older in Campo than in Tremp. Further, we show that both beds are in turn younger than the lowest strata with Ilerdian larger foraminifera at the deep-water Ermua section in the Basque Basin (western Pyrenees). Since the age of stage boundaries must be the same everywhere, the choice of these stratotype sections was misleading, since in practice it resulted in the Ilerdian being used as a facies term rather than as a chronostratigraphic unit. To eliminate that conflict, and yet be respectful with established tradition, we propose to redefine the Ilerdian Stage following a procedure similar to the one used by the International Commission on Stratigraphy to establish global chronostratigraphic standards, namely: by using a “silver spike” to be placed in the Tremp section at the base of the Claret Conglomerate, a widespread lithological unit that in the Tremp Graus Basin coincides with the onset of the CIE. The redefined regional Ilerdian Stage becomes thus directly correlatable to the lower part of the global Ypresian Stage, as currently defined by the International Commission on Stratigraphy.
References
Aubry, M.P., Ouda, K., Dupuis, C., Berggren, W. A.,Van Couvering, J. A., and the Members of the Working Group on the Paleocene/Eocene boundary, 2007. The Global Standard Stratotype-section and Point (GSSP) for the base of the Eocene Series in the Dababiya section (Egypt). Episodes, 30(4), 271-286.
Aubry, M.-P., Berggren, W.A.,Vancouvering, J.A., Ali. J., Brinkuis, H., Cramer, B., Kent, D.K., Swisher III, C.C., Dupuis, C., Gingerich, P.D., Heilmann-Clausen, C., King, C., Ward, D.J., Knox, R. W. O´B., Ouda, K., Stott, L.D., Thiry, M., 2003. Chronostratigraphic terminology at the Paleocene/ Eocene boundary. In: Wing, S.L., Gingerich, P.D., Schmitz, B. and Thomas, E., (eds.). Causes and Consequences of Globally Warm Climates in the Early Paleogene. Geological Society of America Special Paper 369, 551-566.
Baceta, J.I., 1996. El Maastrichtiense superior, Paleoceno e Ilerdiense inferior de la Región Vasco-Cantábrica: secuencias deposicionales, facies y evolución paleogeográfica. Doctoral thesis. Universidad del País Vasco, 372 pp.
Baceta, J.I., Pujalte, V., Serra-Kiel, J., Robador, A., Orue-Etxebarría, X., 2004. El Maastrichtiense final, Paleoceno e Ilerdiense inferior de la Cordillera Pirenaica. In: Vera, J. A. (ed.) Geología de España, Sociedad Geológica de España - Instituto Geológico y Minero de España, 308-313.
Baceta J.I., Pujalte V., Bernaola G., 2005. Paleocene coralgal reefs of the Western Pyrenean basin, northern Spain: New evidence supporting an earliest Paleogene recovery of reefal ecosystems. Palaeogeography, Palaeoclimatology, Palaeoecology, 224, 117-143.
Bains, S., Corfield, R.M., Norris, R.D., 1999. Mechanisms of climate warming at the end of the Paleocene. Science, 285, 724–727.
Bains, S., Norris, R.D., Corfield, R.M., Bowen, G.J., Gingerich P.D., Koch, P.L., 2003. Marine-terrestrial linkages at the Paleocene–Eocene boundary. In: Wing, S.L., Gingerich, P.D., Schmitz, B., Thomas, E. (eds.). Causes and Consequences of Globally Warm Climates in the Early Paleogene. Geological Society of America Special Paper, 369, 49-64.
Berggren, W.A., Kent, D.V., Swisher III, C.C., Aubry, M.P., 1995. A revised Cenozoic geochronology and chronostratigraphy. In: Berggren, W.A., Kent, D.V., Aubry, M.P., Hardenbol, J. (Eds.). Geochronology, Time Scales and Global Stratigraphic Correlations. Society for Sedimentary Geology (SEPM) Spec. Publ. 54, 129-212.
Boukhary, M., Bassiouni, M. E. A., Hussein-Kamel, Y., 1995. Nummulites Luterbacheri, unexpected large nummulites from basal Ilerdian (Early Eocene) from El Quss Abu Said, Farafra oasis, Western Desert, Egypt. Revue de Micropaléontologie, 38, 285-298.
Bowen, G.J., Koch, P.L., Gingerich, P.D., Norris, R.D., Bains, S., Corfield, R.M., 2001. Refined isotope stratigraphy across the continental Paleocene–Eocene boundary on Polecat Bench in the northern Bighorn Basin. In: Gingerich, P.D. (ed.). Paleocene–Eocene Stratigraphy and Biotic Change in the Bighorn and Clarks Fork Basins, Wyoming. University of Michigan Papers on Paleontolology, 33, 73-88.
Bowen, G.J., Clyde, W.C., Koch, P.L., Ting, S., Alroy, J., Tsubamoto, T., Wang, Yu., Wang, Y., 2002. Mammalian Dispersal at the Paleocene/Eocene Boundary. Science, 295, 2062-2065.
Cerling, T.E., 1984. The stable isotopic composition of modern soil carbonate and its relationship to climate. Earth and Planetary Science Letters, 71, 229-240.
Colakoglu, S., Ozcan, E., 2003. Orthophragminid foraminiferal assemblages from an Ilerdian-early Cuisian reference section (Sakarya section, Haymana-Polatli Basin, central Anatolia-Turkey). Revista Italiana di Paleontologia e Stratigrafia, 109 (1), 45-61.
Cuevas J. L., 1992. Estratigrafía del “Garumniense” de la Conca de Tremp. Prepirineo de Lérida. Acta Geologica Hispanica, 27(1-2), 95-108.
De Renzi, M., 1996. La influencia de los factores tafonómicos y paleoecológicos en la distribución de los moluscos en el área tipo del Ilerdiense (Conca de Tremp, Cataluña, España). Revista Española de Paleontología, nº extraordinario, 204-214.
Dickens, G.R., Castillo, M.M., Walker, J.C.G., 1997. A blast of gas in the latest Paleocene: Simulating first-order effects of massive dissociation of oceanic methane hydrate. Geology 25(3), 259-262.
Eichenseer, H., Luterbacher, H., 1992. The marine Paleogene of the Tremp Region (NE Spain) - depositional sequences, facies history, biostratigraphy and controlling factors. Facies, 27, 119–152.
Freytet P., Plaziat J.C., 1970. New elements of lithologic and paleontologic correlation between marine and continental formations of early Eocene in Languedoc Region – Problem of continental Ilerdian. Comptes Rendus des Seances de l’Academie des Sciences, Paris, 270(8), 1076-1079.
García Veigas, F. J., 1988. La formación evaporítica de las facies garumnienses de la Conca de Tremp (Lleida): petrología, geoquímica y sedimentología. Tesis de Licenciatura, Universitat Autónoma de Barcelona, 175 pp.
Giusberti, L., Rio, D., Agnini, C., Backman, J., Fornaciari, E., Tateo, F., Oddone, M., 2007. Mode and tempo of the Paleocene-Eocene thermal maximum in an expanded section from the Venetian pre-Alps. Geological Society of America Bulletin 119 (3/4), 391-412.
Gradstein, F.M., Ogg, J.G., Smith, A.G., Bleeker, W., Lourens, L.J., 2004. A new geologic time scale with special reference to the Precambrian and Neogene. Episodes, 27, 83-100.
Hedberg, H.D. (ed.), 1976. International stratigraphic guide. A guide to stratigraphic classification, terminology and procedure. (International Subcommittee on Stratigraphic Classification, IUGS Commission on Stratigraphy). New York, John
Wiley and Sons, 200 pp.
Hottinger, L., 1998. Shallow benthic foraminifera at the Paleocene-Eocene boundary. Strata, 9, 61-64. Hottinger, L., Schaub, H., 1960. Zur Stufeneinteilung das Paleocaens uns das Eocaens. Einführung der Stufen Ilerdien und Biarritzien. Eclogae Geologicae Helvetiae, 53(1), 453-479.
Institut Cartogràfic de Catalunya, 2002. Mapa geologic de Catalunya. Escala 1:250 000.
Koch, P.L., Zachos, J.C., Dettman, D. L., 1995. Stable isotope stratigraphy and paleoclimatology of the Paleogene Bighorn Basin (Wyoming, USA). Palaeogeography, Palaeoclimatology, Palaeoecology, 115, 61-89.
Koch, P.L., Clyde, W.C., Hepple, R.P., Fogel, M.L., Wing, S.L., Zachos, J.C., 2003. Carbon and oxygen isotope records from
aleosols spanning the Paleocene–Eocene boundary, Bighorn Basin, Wyoming. In: Wing, S.L., Gingerich, P.D., Schmitz, B., Thomas, E. (eds.). Causes and Consequences of Globally Warm Climates in the Early Paleogene. Geological Society of America Special Paper, 369, 49-64.
López-Martínez, N., Peláez-Campomanes, P., 1999. New mammals from south-central Pyrenees (Tremp Formation, Spain) and their bearing on late Paleocene marine-continental correlations. Bulletin de la Société Géologique de France, 170(5), 681-696.
Luterbacher, H.P., 1973. La sección tipo del Piso Ilerdiense. In: Enadimsa (ed.). Libro-Guía del XIII Coloquio Europeo de Micropaleontología (España, 1973), 101-128.
Luterbacher, H.P., Hardenbol, J., Schmitz, B., 2000. Decision of the voting members of the International Subcommission on Paleogene Stratigraphy on the criterion for the recognition of the Paleocene/Eocene boundary. Newsletter of the International Subcommission on Paleogene Stratigraphy, 9, 13.
Luterbacher, H.P., Ali, J.R., Brinkhuis, H., Gradstein, F.M., Hooker, J.J., Monechi, S., Ogg, J.G., Powell, J., Röhl, U., Sanfilippo, A., Schmitz, B., 2004. The Paleogene Period. In: Gradstein, F.M., Ogg J., Smith, A. (eds.). A Geological Timescale 2004. Cambridge, Cambridge University Press, 384-408.
Médus, J., Colombo, F., 1991. Succession climatique et limite stratigraphique Crétacé-Tertiaire dans le N.E. de l’Espagne. Acta Geologica Hispanica, 26, 173-179.
Molina, E., Canudo, J.I., Guernet, C., McDougall, K., Ortiz, N., Pascual, J.O., Parés, J.O., Samsó, J.M., Serra-Kiel, J., Tosquella, J., 1992. The stratotypic Ilerdian revisited: Integrated stratigraphy across the Paleocene/Eocene boundary. Revue de Micropaléontologie, 35, 143-156.
Molina, E., De Renzi, M., Álvarez, G., 1995. El estratotipo del Ilerdiense y su registro fósil. In: G. López et al. (eds.). Actas de las XI Jornadas de Paleontología, 211-220.
Molina, E., Angori, E., Arenillas, I., Monechi, S., Schmitz, B., 2000. Integrated stratigraphy across the Paleocene/Eocene boundary at Campo, Spain. GFF- Geologiska Föreningens i Stockholm Förhandlingar, 122(1), 106-107.
Molina, E., Angori, E., Arenillas, I., Brinkhuis, H., Crouch, E.M., Luterbacher, H., Monechi, S., Schmitz, B., 2003. Correlation between the Paleocene/Eocene boundary and the Ilerdian at Campo, Spain. Revue de Micropaléontologie, 46(2), 95-109.
Murru, M., Ferrera, C., Da Pelo, S; Ibba, A., 2003. The Palaeocene-Middle Eocene deposits of Sardinia (Italy) and their palaeoclimatic significance. Comptes Rendus Geoscience, 335 (2): 227-238.
Orue-Etxebarria, X., Apellaniz, E., Baceta, J.I., Coccioni, R., Di Leo, R., Dinarès-Turell, J., Galeotti, S., Monechi, S., Núñez Betelu, K., Parés, J.M., Payros, A., Pujalte, V., Samsó, J.M., Serra-Kiel, J., Schmitz, B., Tosquella, J., 1996. Physical and biostratigraphic analysis of two prospective Paleocene–Eocene Boundary stratotypes in the intermediate-deep water Basque Basin, western Pyrenees: The Trabakua Pass and Ermua sections. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 201, 179-242.
Orue-Etxebarria, X., Pujalte, V., Bernaola, G., Apellaniz, E., Baceta, J.I., Payros, A., Núñez-Betelu, K., Serra-Kiel, J., Tosquella, J., 2001. Did the Late Paleocene thermal maximum affect the evolution of larger foraminifers? Evidence from calcareous plakton of the Campo Section (Pyrenees, Spain). Marine Micropaleontology, 41, 45-71.
Ozgen-Erdem, N., Akyazi, M., Karabasoglu, A., 2007. Biostratigraphic interpretation and systematics of Alveolina assemblages from the Ilerdian-Cuisian limestones of Southern Eskisehir, Central Turkey. Journal of Asian Earth Sciences, 29 (5-6), 911-927
Payros, A., Pujalte, V., Baceta, J.I., Bernaola, G., Orue-Etxebarria, X., Apellaniz, E., Caballero, F., Ferràndez, C., 2000. Lithostratigraphy and sequence stratigraphy of the upper Thanetian to middle Ilerdian strata of the Campo section (southern Pyrenees, Spain): revision and new data. Revista de la Sociedad Geológica de España, 13(2), 213-226.
Plaziat, J.C., 1975. L’Ilerdien à l’intérieur du Paléogène languedocien; ses relations avec le Sparnacien, l’Ilerdien sudpyrénéen, l’Yprésien et le Paléocène. Bulletin de la Société Géologique de France, 17(2), 168-182.
Plaziat, J.C., 1981, Late Cretaceous to late Eocene palaeogeographic evolution of Southwest Europe. Palaeogeography, Palaeoclimatology, Palaeoecology, 36, 263-320.
Pomerol, Ch., 1975. La signification de l’Ilerdien et l’intérêt de cet étage dans la stratigraphie du Paléogène mésogéen. B. S.
G. F., XVII, 213-217.
Puigdefàbregas, C., Souquet, P., 1986. Tectosedimentary cycles and depositional sequences of the Mesozoic and Tertiary from the Pyrenees. Tectonophysics, 129, 173-203.
Pujalte, V., Orue-Etxebarria, X., Schmitz, B., Tosquella, J., Baceta, J.I., Payros, A., Bernaola, G., Caballero, F., Apellaniz, E., 2003a. Basal Ilerdian (earliest Eocene) turnover of larger foraminifera: age constraints based on calcareous plankton and δ13C isotopic profiles from new southern Pyrenean sec tions (Spain). In: Wing, S.L., Gingerich, P.D., Schmitz, B., Thomas, E. (eds.). Causes and Consequences of Globally Warm Climates in the Early Paleogene. Geological Society of America Special Paper, 369, 205-221.
Pujalte, V., Dinarès-Turell, J., Bernaola, G., Baceta, J.I., Payros, A., 2003b. A reappraisal of the position of chron C25n in the Campo section (Huesca province, south-central Pyrenees). Geogaceta, 34, 155-158.
Pujalte, V. Schmitz, B., 2005: Revisión de la estratigrafía del Grupo Tremp («Garumniense», Cuenca de Tremp-Graus, Pirineos meridionales). Geogaceta, 38, 79-82.
Pujalte, V., Schmitz, B., 2006 : Revised lithostratigraphy of the Tremp Group. In: Baceta, J.I., Pujalte, V., and Caballero, F (eds.). Paleocene and Early Eocene facies and events: a Basin-Platform-Coastal Plain Transect (south-central and western Pyrenees). Post-conference field trip Guidebook, CBEP 2006. 63-69.
Pujalte, V., Schmitz, B., Baceta, J.I., Orue-Etxebarria, X., Bernaola, G., Dinarès-Turell, J., Payros, A., Apellaniz, E., Caballero, F., 2009. Correlation of the Thanetian Ilerdian turnover of larger foraminifera and the Paleocene-Eocene thermal maximum: confirming evidence from the Campo area (Pyrenees, Spain). Geologica Acta, 7(1-2), 161-175.
Rasser M.W., Scheibner C., Mutti M., 2005. A paleoenvironmental standard section for Early Ilerdian tropical carbonate factories (Corbieres, France; Pyrenees, Spain). Facies 51(1-4), 227-242.
Remane, J., Bassett, M.G., Cowie, J.W., Gohrbandt, K.H., Lane, H.R., Michelsen, O., Naiwen, W., 1996. Revised guidelines for the establishment of global chronostratigraphic standards by the International Commission of Stratigraphy (ICS). Episodes, 19, 77-81.
Robador, A., Zamorano, M., in press. Mapa Geológico de España. Scale 1:50.000, 2nd series, nº. 212, Campo. Madrid, Instituto Geológico y Minero de España, 1 fold. map.
Robador, A., 2005. El Paleoceno e Ilerdiense inferior del Pirineo occidental: Estratigrafía y sedimentología. Doctoral thesis, Universidad del País Vasco, 456 p.
Röhl, U., Bralower, T.J., Norris, R.D., Wefer, G., 2000. New chronology for the late Paleocene thermal maximum and its environmental implications. Geology, 28, 927-930.
Röhl, U., Westerhold, T., Bralower, T.J., Zachos, J.C., 2007. On the duration of the Paleocene-Eocene thermal maximum (PETM). Geochemistry, Geophysics, Geosystems, 8 (12), 1-13.
Rosell, J., 1994. Mapa Geológico de España. Scale 1:50.000, 2nd series, nº. 252, Tremp. Madrid, Instituto Tecnológico Geominero de España, 63 pp., 1 fold. map.
Salvador, A., (ed.), 1994. International Stratigraphic Guide (2nd edition). A guide to stratigraphic classification, terminology and procedure. Trondheim (Norway), International Union of Geological Sciences and The Geological Society of America, 214 p.
Schaub, H., 1969. L’Ilerdien; état actuel du problème. Colloque sur l’Eocene, Paris, 1968. Mèmoirs Bulletin Recherches Geologiques et Minieres, 69, 259-261.
Schaub, H., 1973. La sección de Campo (Prov. de Huesca). In: Libro-Guía del XIII Coloquio Europeo de Micropaleontología (España, 1973) (ed. Enadimsa), 139-158.
Schaub, H., 1973. La sección de Campo (Prov. de Huesca). In: Libro-Guía del XIII Coloquio Europeo de Micropaleontología (España, 1973) (ed. Enadimsa), 139-158.
Schaub, H.,1992. The Campo section (NE Spain), a Tethyan parastratotype of the Cuisian. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 186, 63-70.
Scheibner, C., Rasser, M.W., Mutti, M., 2007. The Campo section (Pyrenees, Spain) revisited: Implications for changing benthic carbonate assemblages across the Paleocene–Eocene boundary. Palaeogeography, Palaeoclimatology, Palaeoecology, 248, 145-168.
Scheibner, C., Speijer, R.P., 2009: Recalibration of the Tethyan shallow-benthic zonation across the Paleocene-Eocene boundary: the Egyptian record. Geologica Acta, 7(1-2), 195-214.
Schmitz, B., Asaro, F., Molina, E., Monechi, S., von Salis, K., Speijer, R.P., 1997. High-resolution iridium, δ13C , δ18O, foraminifera and nannofossil profiles across the latest Paleocene benthic extinction event at Zumaya, Spain. Palaeogeography, Palaeoclimatology, Palaeoecology, 133, 49-68.
Schmitz, B., Pujalte, V., Núñez-Betelu, K., 2001. Climate and sealevel perturbations during the Initial Eocene Thermal Maximum: evidence from siliciclastic units in the Basque Basin (Ermua, Zumaia and Trabakua Pass), northern Spain. Palaeogeography, Palaeoecology, Palaeoclimatology 165, 299-320.
Schmitz, B., Pujalte, V., 2003. Sea-level, humidity, and land-erosion records across the initial Eocene thermal maximum from a continental-marine transect in northern Spain. Geology, 31, 689-692.
Schmitz, B., Pujalte, V., 2007. Abrupt increase in seasonal extreme precipitation at the Paleocene-Eocene boundary. Geology, 35, 215–218.
Serra-Kiel, J., Canudo, J.I., Dinarés, J., Molina, E., Ortiz, N., Pascual, J.O. Samsó, J.M., Tosquella, J., 1994. Cronoestratigrafía de los sedimentos marinos del Terciario inferior de la Cuenca de Graus-Tremp (Zona Central Surpirenaica). Revista Sociedad Geológica de España, 7(3-4), 273-297.
Serra-Kiel, J., Hottinger, L., Caus, E., Drobne, K., Ferràndez, C., Jauhri, A.K., Less, G., Pavlovec, R., Pignatti, J., Samsó, J.M., Schaub, H., Sirel, E., Strougo, A., Tambareau, Y., Tosquella, J., Zakrevskaya, E., 1998. Larger foraminiferal biostratigraphy of the Tethyan Paleocene and Eocene. Bulletin de la Société Géologique de France, 169, 281-299.
Tambareau, Y., 1972. Thanétien supérieur et Ilerdien inférieur des Petites Pyrénées, du Plantaurel et des Chaînons audois. Doctoral thesis. Universite de Toulouse, 377 pp.
Tambareau,Y., Villatte, J., 1974. Le passage Thanétien-Ilerdien dans la región de Campo: comparison avec les Petites Pyrénées. Bulletin Histoire Naturelle de Toulouse 110, 340-361.
Tambareau, Y., Feist, M., Gruas-Cavagnetto, C., Murru M., 1989. Characterization of the continental Ilerdian in the Western Mediterranean area. Comptes Rendus de l’Ácademie des Sciences, 308(7), 689-695.
Thiry, M., Aubry, M-P., Dupuis, C., Sinha, A., Stott, L.D., Berggren, W.A., 2006. The Sparnacian deposits of the Paris Basin: d13C isotope stratigraphy. Stratigraphy, 3, (2), 119-138.
Tosquella, J., Serra-Kiel, J., Ferràndez-Cañadell, C., Samsó, J.M., 1996 (pub. 1998). Las biozonas de nummulítidos del Paleoceno Superior-Eoceno Inferior de la Cuenca Pirenaica. Acta Geologica Hispanica, 31(1-3), 23-36 (with English Abridged version).
Vergés, J., Martínez, A., 1988. Corte compensado del Pirineo oriental: Geometría de las cuencas de antepaís y edades de emplazamiento de los mantos de corrimiento. Acta Geologica Hispanica, 23, 95-106.
Wright, V.P. and Marriott, S. B. 1996. A quantitative approach to soil occurrence in alluvial deposits and its application to the Old Red Sandstone of Britain. Journal of the Geological Society, London, 153, 907-913.
Zachos, J.C., Wara, M.W., Bohaty, S., Delaney, M.L., Petrizzo, M.R., Brill, A., Bralower, T.J., Premoli Silva, I., 2003. A transient rise in tropical sea surface temperature during the Paleocene–Eocene Thermal Maximum. Science, 302, 1551-1554.
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