Correlation of the Thanetian-Ilerdian turnover of larger foraminifera and the Initial Eocene thermal maximum (IETM) confirming evidence from the Campo area (Pyrenees, Spain)

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FIELD TRIP TO THE YPRESIAN/LUTETIAN BOUNDARY AT THE GORRONDATXE BEACH SECTION (BASQUE COUNTRY, W PYRENEES)

One of the Paleogene Stage boundaries still needing official definition is the Ypresian/Lutetain (Early- Middle Eocene) boundary. With the aim of contributing to attain this definition, a high-resolution multidisciplinary study, including physical stratigraphy (lithostratigraphy, sequence stratigraphy and magnetostratigraphy) and biostratigraphy (calcareous nannofossil, planktic foraminifer and larger foraminifer), has been carried out over the 700 m thick uppermost Ypresian – lower Lutetian Gorrondatxe section. The results show that the different events traditionally used to place the Ypresian/Lutetian boundary, hitherto thought to be simultaneous (i.e., the planktic foraminifer P9 (=E7) / P10 (=E8) Zone boundary; the calcareous nannofossil CP12a / CP12b Subzone boundary; the larger foraminifer SBZ12 / SBZ13 Zone boundary; and the boundary between magnetic polarity chrons C22n and C21r), actually occur at very different levels. Therefore, before considering any section to place the Ypresian/Lutetian boundary stratotype, the criterion to precisely define this boundary should be selected. To this end, the succession of events pinpointed in the Ypresian/Lutetian boundary interval of the Gorrondatxe beach section might prove a useful database. The Gorrondatxe section fulfils most of the requirements demanded of a prospective stratotype section. In addition, the great sedimentary thickness, which implies a very high deep-marine sedimentation rate, provides the Gorrondatxe section an additional value, as it offers the opportunity to chronologically order successive biomagnetostratigraphic events more precisely than elsewhere. Therefore, we consider that, once the criterion to define the Ypresian/Lutetian boundary is selected, the Gorrondatxe beach section should be deemed a firm candidate to place the Global Stratotype Section and Point of the base of the Lutetian Stage

The Global Stratotype Section and Point (GSSP) for the base of the Lutetian Stage at the Gorrondatxe section, Spain

The GSSP for the base of the Lutetian Stage (early/ middle Eocene boundary) is defined at 167.85 metres in the Gorrondatxe sea-cliff section (NW of Bilbao city, Basque Country, northern Spain; 43º22'46.47" N, 3º 00' 51.61" W). This dark marly level coincides with the lowest occurrence of the calcareous nannofossil Blackites inflatus (CP12a/b boundary), is in the middle of polarity Chron C21r, and has been interpreted as the maximumflooding surface of a depositional sequence that may be global in extent. The GSSP age is approximately 800 kyr (39 precession cycles) younger than the beginning of polarity Chron C21r, or ~47.8 Ma in the GTS04 time scale. The proposal was approved by the International Subcommission on Paleogene Stratigraphy in February 2010, approved by the International Commission of Stratigraphy in January 2011, and ratified by the International Union of Geological Sciences in April 2011.Published86-1082.2. Laboratorio di paleomagnetismoJCR Journalrestricte

Correlation of the Thanetian-Ilerdian turnover of larger foraminifera and the Paleocene-Eocene thermal maximum: confirming evidence from the Campo area (Pyrenees, Spain)

Abstract in UndeterminedIt has long been known that a major larger foraminifera turnover (LFT) occurred at the boundary between the Thanetian and Ilerdian stages, but its possible correlation with the Paleocene-Eocene thermal maximum (PETM) was unsuspected until the work of Baceta (1996), and has been controversial ever since. After summarizing the history of this controversy, we present information from three new sections that conclusively resolve the issue, all of them placed less than 2 km to the east of the classical Campo section in the southern Pyrenees. In these three sections, an up to 7 meter-thick intercalation of continental deposits rich in pedogenic carbonate nodules is sandwiched between uppermost Thanetian and lowermost Ilerdian shallow marine carbonates. The delta(13)C composition of 42 pedogenic nodules collected from two of these sections (San Martin and La Cinglera) ranges between -11.4 and -14.3% and averages -12.9%, values that conclusively represent the PETM and for the first time are recorded in sections where the LFT is clearly represented. Further, a high-resolution lithological correlation between Campo and the three new sections across the P-E interval unquestionably demonstrates that the lowermost marine beds with autochthonous specimens of Alveolina vredenburgi (a tell-tale of the LFT) are laterally interfingered -and are therefore coeval- with the nodule-bearing PETM continental deposits. On the basis of the new evidence, the temporal coincidence of the PETM and the LFT can no longer be doubted

The changing character of shallow and deep-water carbonate deposition during a 2nd-order transgressive-regressive facies cycle : the example of the Paleogene of the SW Pyrenees

Payros A., Baceta J.I., Orue-Etxebarria X., Pujalte V., Serra-Kiel Josep. The changing character of shallow and deep-water carbonate deposition during a 2nd-order transgressive-regressive facies cycle : the example of the Paleogene of the SW Pyrenees. In: Géologie Méditerranéenne. Tome 21, numéro 3-4, 1994. Perimediterranean carbonate platforms. First International Meeting. Marseille – France (5-8 septembre 1994) sous la direction de Jean-Pierre Masse. pp. 141-143

Closing the Mid- Paleocene gap: toward a complete astronomically tuned Paleocene Epoch and Selandian and Thanetian GSSPs at Zumaia (Basque Basin, W Pyrenees)

An integrated magneto-, bio- and cyclostratigraphic framework is presented for the Mid-Palaeocene interval from the (hemi) pelagic sea-cliff section of Zumaia in the Basque basin. The new ∼55 m long studied section expands about 3.5 Myr and closes the gap between previously published integrated studies in the section. The occurrence of magnetochron C26n is now documented, and its duration (complemented also by data from the Ibaeta section), and that for chrons C26r and C25r is estimated by counting precession related lithologic couplets assigned to have 21-kyr duration (C25r=∼1449 kyr, C26n=∼231 kyr, C26r=∼2877 kyr). Consequently, the Zumaia section now provides the first complete Palaeocene astronomically derived chronology, rendering this section a master reference section. Due to limitations in the orbital calculations and uncertainties in the radiometric dating method no robust tuning and absolute ages can be given for the moment. However, the FOs (First Occurrences) of key calcareous plankton species and the Mid Palaeocene Biotic Event (MPBE) are placed within the magnetostratigraphic and cyclostratigraphic template along the studied Mid-Palaeocene interval. In addition, the dataset provides the key elements for a proper settling of the Thanetian and Selandian Global Stratotype Section and Point (GSSPs), which is one of the primary objectives of the ICS (International Commission of Stratigraphy). We consider the base of chron C26n and the criteria associated to the lithostratigraphic change between the Danian Limestone Fm and the Itzurun marl Fm at Zumaia, as the respective delimiting points for the Thanetian and Selandian bases as recently agreed by the Paleocene Working Group of the International Subcommission of the Paleogene Stratigraphy of the ICS. Consequently, the duration of the Thanetian, Selandian and Danian component stages can be estimated at Zumaia to be about ∼3129 kyr, ∼2163 kyr and ∼4324 kyr respectively (see text for error considerations). However, the MPBE located 8 precession cycles below the base of C26n in correspondence to a short eccentricity maxima at Zumaia, could also serve as a guiding criteria to approximate or redefine the Thanetian base if this level demonstrated synchronous.Published450–4672.2. Laboratorio di paleomagnetismoJCR Journalreserve