The Upper Ypresian and Lutetian in San Pelegrín section (Southwestern Pyrenean Basin): Magnetostratigraphy and larger foraminifera correlation A. Rodríguez-Pintó a, b, ⁎, E.L. Pueyo a , J. Serra-Kiel c , A. Barnolas d , J.M. Samsó d , A. Pocoví b a Instituto Geológico y Minero de España, Unidad de Zaragoza, c/Manuel Lasala 44, 50006 Zaragoza, Spain b Departamento de Ciencias de la Tierra, Universidad de Zaragoza, c/Pedro Cerbuna 12, 50009 Zaragoza, Spain c Departament d'Estratigrafia, Paleontologia i Geociències Marines, Universitat de Barcelona, C/Martí i Franquès, s/n, 08028 Barcelona, Spain d Instituto Geológico y Minero de España, c/La Calera s/n Ríos Rosas 23, 28003 Tres Cantos, Madrid, Spain abstract article info Article history: Received 10 February 2012 Received in revised form 30 September 2012 Accepted 8 October 2012 Available online 2 November 2012 Keywords: Magnetostratigraphy Biostratigraphy Larger foraminifera Ypresian–Lutetian Shallow Benthic Zones Pyrenean Basin The current available Shallow Benthic Zones (SBZs) calibration based on larger foraminifera is now being im- proved for the Paleogene Period. In this work, the San Pelegrín section in the External Sierras, shows new magnetostratigraphic and biostratigraphic information from the Southwestern Pyrenean basin, where the larger thickness of the shallow marine platforms were developed. This environment represents the appropri- ate frame to calibrate the SBZ scale. Moreover the magnetostratigraphic data can be correlated with biostrat- igraphic data obtained directly at the same section, avoiding limitations of previous correlations. The San Pelegrín section presents 530 m of Ypresian and Lutetian rocks; 169 sampled levels for magnetostratigraphic purposes have been studied, a fact that guarantees the independence and resolution of this record. Thermal and alternating field demagnetizations were carried out to unravel the characteristic remanent magnetiza- tion, and the orthogonal diagrams show stable normal and reverse polarity directions. Three pairs of magnetozones were found along the section enabling to define a robust and reliable local polarity sequence correlated with chrons C23, C22, C21n and C20r. The biostratigraphic study distinguished three Shallow Benthic Zones from SBZ11 to SBZ13. The combination of magneto and biochronologic scales is very useful to improve and to accurate the available shallow benthic zone calibration for this time gap, especially for the SBZ11 zone. Now the base of SBZ11 can be located, at least, in 50.96 My, because the association is still present at the top of C23n. This data is older than previously thought from existent scales. On the other side, the SBZ11 top falls within chron C22n. The occurrence of a sedimentary hiatus between C22n and C21n prevents an accurate calibration of the SBZ12 top, but our profile proves the relation of SBZ12 with C22n as well. Finally the SBZ13 zone falls within the limits of recent recalibrations (C21n to C20r). © 2012 Elsevier B.V. All rights reserved. 1. Introduction The accurate calibration of the Ypresian/Lutetian (Y/L) boundary (Molina et al., 2011) has raised the scientific interests in Ypresian and Lutetian sections the last decade. Among the multidisciplinary and inte- grated studies done, we should particularly mention magneto-, bio-, chrono- and cyclostratigraphic studies in the Pyrenean domain; as in Gorrondatxe (Bernaola et al., 2006; Payros et al., 2007, 2009a,b; Ortiz et al., 2011), Otsakar (Payros et al., 2011), Ara (Mochales et al., 2012), Isuela (Rodríguez-Pintó et al., 2012), or in the Betics: Agost (Larrasoaña et al., 2008; Ortiz et al., 2008). Nevertheless, most of these sections share a hemipelagic environment with turbidite facies in which the larger foraminifera are scarce or can be reworked from their original location; therefore, the larger foraminifera record could have a distorting effect on the calibration of the Shallow Benthic Zones (SBZs). The hemipelagic environment also conditions the condensation of the sedimentary record and many of these sections hardly reach a hun- dred of meters (Agost Larrasoaña et al. (2008), Lizarraga Payros et al. (2009b), Otsakar Payros et al. (2011)). Another problem dealing with the larger foraminifera is related to the density and quality (availability) of sampling. The first biozonation based on nummulitids (larger foraminifera) for late Ypresian times (regionally known as Cuisian in the Pyrenees) was proposed by Schaub (1966, 1981). This biozonation was based on Nummulites and Assilina genera and it was correlated with calcareous nanoplankton in the Campo section in the South Pyrenean basin (Kapellos and Schaub, 1973). Subsequently, Serra-Kiel et al. (1998) characterized the late Ypresian SBZ starting from the biozones defined by Schaub (Kapellos and Schaub, 1973) and integrating data from Hillebrandt (1965) also from the Campo section. The definition and temporal calibration of these biozones (Serra-Kiel et al., 1998) also took into consideration the magnetostratigraphic data available Palaeogeography, Palaeoclimatology, Palaeoecology 370 (2013) 13–29 ⁎ Corresponding author at: Departamento de Ciencias de la Tierra, Universidad de Zaragoza, c/Pedro Cerbuna 12, 50009 Zaragoza, Spain. E-mail addresses: adriana@igme.es (A. Rodríguez-Pintó), unaim@igme.es (E.L. Pueyo), josepserra@ub.edu (J. Serra-Kiel), a.barnolas@igme.es (A. Barnolas), josemsamso@gmail.com (J.M. Samsó), apocovi@unizar.es (A. Pocoví). 0031-0182/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.palaeo.2012.10.029 Contents lists available at SciVerse ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo