J.M. Samsó’s research while affiliated with University of Zaragoza and other places

In this paper we present new magnetostratigraphic data performed in the lower part of the Gabardiella section. Sixty-three levels were sampled in 218 m with the aim to determine the Cuisian- Lutetian boundary at this location. Despite the limited quality of the data, we observe normal and reverse primary directions with a mean of (n, D, I, Alfa95 & k: 25, 037, 49, 18, 3). As a result it is presented the paleomagnetic LPS data and its correlation with the GTPS and pre-existent biostratigraphic studies. We could correlate the Garbardiella LPS with C22 – C20r chrons. The Cuisian –Lutetian boundary seems to be eroded as in other locations of the basin, and the chron C20 is very well developed as pre-existent data pointed out.

The La Pardina Formation is a siliciclastic-dominated unit up to 26 m thick intercalated within a 300 m thick Danian–lower Ilerdian succession of shallow marine carbonates in the southern Pyrenees. The unit is composed of four interdigitated facies, three of them of a coarse-grained siliciclastic character (Sf1, Sf2, Sf3), and the fourth one composed of bioclastic packstones with argillaceous matrix (calcareous facies, Cf). The siliciclastic facies make up the bulk of the La Pardina Formation in the Ordesa-Monte Perdido National Park, while the Cf is subordinate in the Park but widespread throughout the southern Pyrenees. Biostratigraphic and isotopic data suggest that the Cf pertains to the Paleocene–Eocene Thermal Maximum (PETM). No isotopic or biostratigraphic information could be obtained from the siliciclastic facies, but they are also assigned to the PETM because of their interfingering with the Cf. The siliciclastic facies were accumulated in a braid delta system fed by either a major river or by several minor rivers draining the Ebro Massif. The Sf3, Sf2 and Sf1 respectively represent the top-set, foreset and bottomset parts of the braid delta, whereas the Cf correspond to the prodelta. In proximal parts of the braid delta the Sf3 overlies a subaerial surface carved into upper Thanetian marine carbonates, a proof of a pre-PETM sea-level fall. In the remainder of the braid delta, the La Pardina Formation exhibits an overall thickening-coarsening-up trend that attests to rapid progradation. The development of the braid delta implies a dramatic increase in the influx of both coarse- and fine-grained siliciclastics, which temporarily halted a long-lasting period of carbonate-dominated sedimentation. This abrupt change demonstrates that the environmental impact caused by the intensification of the hydrological cycle during the PETM was particularly severe at middle latitudes.

The Geological Survey of Spain (IGME) in cooperation with the National Park Authorities has started the edition of a new tourist guidebook series: the National Park Geological Guidebooks. This new series intends to answer the growing social demand of geological guides in natural protected areas. The geological guide of the Ordesa and Monte Perdido National Park has been the six published volume of this series. The text includes a complete description of the main geological units of the park and of the events that mark the geological evolution of the whole Pyrenees. As a consequence the Sobrarbe Geopark has a new tool for the geological heritage dissemination. A French edition of this book is also published under the sponsorship of the Sobrarbe Geopark, due to its boundary location.

Ce guide fournit au lecteur des cartes topographiques et géologiques simplifiées pour une meilleure compréhension dans le dos de couverture. CHAPITRE I: LA CHAÎNE P 10 Dans la première partie on introduit le lecteur aux concepts de base de la géologie à travers le contexte géologique des Pyrénées. De cette manière, on comprendra l'origine des roches, la déformation qui ont subi et la configuration actuelle du relief par l'action des glaciers et la dissolution karstique. Photos Blocs diagramme CHAPITRE II: LA GÉOLOGIE DU PARC NACIONAL P 48 un contexte géologique exceptionnel. La deuxième partie correspond à la description des principales caractéristiques géologiques du parc. Le parc et ses environs, mise à part la beauté de ses paysages, nous donnent l'occasion d'observer plusieurs caractéristiques géologiques intéressantes telles que des séquences de roches sédimentaires, leur déformation tectonique pour construire les montagnes et les événements les plus récents qui l'ont affecté comme les glaciations et la dissolution karstique. Dans chaque itinéraire on spécifie la thématique géologique avec une icône. textes explicatifs Photos Illustrations et diagrammes explicatifs CHAPITRE III: ITINÉRAIRES P 90 La troisième partie se compose par la description des routes à travers le parc. Onze ont été choisis, en utilisant comme critère principal leur accessibilité et popularité, ainsi comme la qualité des observations géologiques. Chacune est identifiée par une couleur, la même pour la carte et pour la description de l'itinéraire. Chaque voyage commence avec les informations suivantes: icônes du type de phénomène géologique qui peut être observé, le type d'accès (voiture ou à pied) et sa difficulté, un résumé et une brève description. une autre icône indique la page où vous pouvez trouver de plus amples renseignements et un symbole (marteau), qui, avec sa couleur, indique le degré de difficulté de compréhension des concepts géologiques.

The current available Shallow Benthic Zones (SBZs) calibration based on larger foraminifera is now being improved 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 appropriate frame to calibrate the SBZ scale. Moreover the magnetostratigraphic data can be correlated with biostratigraphic 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 magnetization, 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).