A prospective Early Late Paleocene event (ELPE) from the expanded Río Gor hemipelagic section (Betic Cordillera, southern Spain): Foraminifera, nannofossil and isotopic data

The Río Gor section (Pujalte et al., 2012) is far more expanded and complete than Alamedilla, so far the most studied lower Paleogene hemipelagic section of the Betic Cordillera (e.g., Arenillas & Molina, 1996). This fact is specially striking in the Paleocene succession, which in Río Gor is about 250 metres thick and probably continuous (Fig. 1A) while in Alamedilla is less than 20 metres thick (Fig. 1B), with an important hiatus comprising most of the Danian, the entire Selandian and the lower part of the Thanetian (Pujalte et al., 2012). The probability of locating Paleocene hyperthermals is, therefore, far greater in Río Gor than in Alamedilla. The Paleocene is mainly represented at Río Gor by greycoloured lithologies, the lower part of the section being formed by alternating calcarenites and marls, the remainder by marls and marly limestones. However, intercalated within these grey marly lithologies, there occurs an interval ca. 10 m thick of a prominent red colour (Figs. 1A, C) that, on a preliminary survey, was tentatively assigned to the PETM (Pujalte et al., 2012). The more detailed study herein presented, based on analyses of foraminifera, calcareous nannofossil and carbon isotope composition of dispersed organic matter of 26 samples, leads to a different interpretation. It is concluded that the studied interval contains what is probably the most expanded record of the ELPE reported to date, with part 2 recording a comparatively long period of stressed oceanic conditions, part 3 the climax of the event and part 4 the recovery to normal background conditions indicated by part 5. In the stratotypic Zumaia section (western Pyrenees) the core of the ELPE was found to occur eight precession cycles below the GSSP of the Thanetian Stage, situated at the base of magnetochron C26n (Bernaola et al.,2007; Schmitz et al., 2011). It is thus a good criterion to approximate the Selandian/Thanetian boundary, its utility being reinforced by its finding in the Betic Cordillera.