253 Dinarès-Turell, J., Pujalte, V., Stoykova, K. y Elorza, J. 2013. Detailed correlation and astronomical forcing within the Upper Maastrichtian succession in the Basque Basin. Boletín Geológico y Minero, 124 (2): 253-282 ISSN: 0366-0176 Detailed correlation and astronomical forcing within the Upper Maastrichtian succession in the Basque Basin J. Dinarès-Turell (1) , V. Pujalte (2) , K. Stoykova (3) y J. Elorza (4) (1) Istituto Nazionale di Geoisica e Vulcanologia, Via di Vigna Murata 605, I-00143 Rome, Italy (2) Department of Stratigraphy and Paleontology, Fac. Science and Technology, University of the Basque Country UPV/EHU, PO Box 644, E-48080 Bilbao, Spain (3) Department of Paleontology and Stratigraphy, Geological Institute, Bulgarian Academy of Science, BG-1113 Soia, Bulgaria (4) Department of Mineralogy and Petrology, Fac. Science and Technology, University of the Basque Country UPV/EHU, PO Box 644, E-48080 Bilbao, Spain ABSTRACT We have undertaken a comprehensive, integrated, cyclo-magnetostratigraphic analysis and study of the cal- careous nannofossils of the Upper Maastrichtian hemipelagic succession in three sections of the Basque Basin (Zumaia, Sopelana and Hendaia). The sections were correlated at bed-by-bed scale through careful analysis of the lithological stacking pattern and signiicant sedimentary features. For spectral analysis we used an available high-resolution carbonate proxy record spanning 64 m of section below the K/Pg (Cretaceous/ Palaeogene) boundary at Zumaia containing 72 precession-related limestone-marl couplets. The continuous wavelet spectrum helped to determine and visualize the orbital forcing at both the short (~100-ky) and long (405-ky) eccentricity band. We applied bandpass Gaussian ilters to the carbonate record to extract the rel- evant periodicities and provide a cycle-numbering scheme starting at the K/Pg boundary. The full hierarchy of precession cycles and eccentricity-related bundles is then extended toward the base of the section in question, which contains a total of 33 short eccentricity-related bundles, thus spanning more than 3 Ma. The chron C31r/ C31n boundary (estimated to occur at ~3.08 Ma below the K/Pg boundary) in the lower part of the succession was determined unambiguously in all three sections studied although the C30n/C29r reversal could not be determined due to a pervasive reverse magnetization acting on the purplish lithologies in the upper part of the succession. Relevant calcareous plankton bioevents could be accurately placed on the cyclo-magnetostrati- graphic template. The cyclostratigraphic framework also allowed us to estimate the duration of previously deined sea-level-related 3 rd -order depositional sequences in the basin, which appear to be strongly paced by the long-term 1.2 My obliquity amplitude modulating cycle. This is an outstanding feature in the Maastrichtian greenhouse period, during which continental ice sheets are expected to be either ephemeral or non-existent. This is a matter that deserves further attention. Key words: calcareous nannofossils, cyclostratigraphy, depositional sequences, Milankovitch, magnetostrati- graphy Correlación detallada y control orbital de la sucesión del Maastrichtiense Superior de la Cuenca Vasca RESUMEN Se presenta un estudio exhaustivo ciclo-magnetostratigráico y de nanofósiles calcáreos de tres secciones de la sucesión hemipelágica del Maastrichtiense Superior de la Cuenca Vasca (Zumaia, Sopelana y Hendaia). La correlación entre secciones se realiza capa a capa mediante un análisis minucioso del patrón del apilamiento litológico y detalles sedimentarios. Para el análisis espectral se utiliza un registro de carbonato de alta resolu- ción de un intervalo de 64 m debajo del límite K/Pg (Cretácico/Paleógeno), disponible en Zumaia, que contine 72 pares marga-caliza relacionados con el ciclo de precesión. El espectro continuo de ondas pequeñas ayuda a determinar y visualizar el control orbital en las bandas de la excentricidad corta (~100-ka) y larga (405-ka). Se han usado iltros gausianos pasabanda sobre el registro de carbonato para extraer las periodicidades relevan- tes y se aporta un esquema de numeración de ciclos que se inicia en el límite K/Pg. A continuación, la jerarquía