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Chert from the limestones and marly limestones of Castelltallat Formation (Ebro Basin) was widely used throughout prehistoric times in north-eastern Iberia to produce stone tools due to its properties and accessibility. A rough estimate indicates that this rock—either as raw material or as lithic products—was distributed mainly to the north of the outcrops, over an area of 6000–8000 km2. However, other rocks in the area have similar characteristics which can lead to confusion in the interpretation of its prehistoric use and distribution. In order to establish useful archaeometric criteria for differentiating this chert from other similar, the Castelltallat chert is characterised in petrographic, mineralogical and geochemical terms. The chert nodules are found to be homogenous at the macroscopic and microscopic level, with a significant presence of bioclasts, thus indicating they might be formed in a freshwater lake environment by the early diagenetic replacement of carbonates in shallow waters. The mineralogical composition is homogeneously uniform and of a flint type, characterised by an almost exclusive predominance of quartz, without any opaline phases, and a variable proportion of moganite. The iron oxide content is very low, whereas its chemical composition is unusually high in uranium which correlates positively with carbonate content and negatively with silica. Archaeometrical parameters are provided to reach a proper identification of tools knapped with this chert. This way, chert from Castelltallat Formation turns out to be a valuable lithological marker to evaluate the range of mobility of the human groups who lived in the north-eastern Iberia and their contacts with neighbouring areas., The fieldwork to obtain rock samples and the analysis of the samples was cofunded by the Direcció General del Patrimoni Cultural de la Generalitat de Catalunya and IMF-CSIC, within the framework of an interinstitutional collaboration agreement for the development of the Catalan Lithotheque of siliceous rocks (LITOcat project). Specific studies on the petrological characterisation of Castelltallat chert and its prehistoric use were carried out within the research project ‘Aprofitament prehistòric i històric del sílex a Catalunya: contextos extractius i de primera transformació’, funded by the Department of Culture of the Government of Catalonia (ref. núm. 2014/100778). The significance of human use and scope of distribution of Castelltallat chert are being approached within the project ‘Productions, technical variability and technological innovation in the Neolithic’, funded by the Spanish Ministry of Economy and Competitiveness (Grant HAR2016–76534-C2–2-R).

La Plana de Vic, situada hacia el sector NE de la Cuenca del Ebro, se caracteriza por un espeso apilamiento de materiales marinos que fueron acumulados principalmente durante el Paleógeno. Sobre una discordancia desarrollada sobre el basamento paleozoico se acumularon materiales aluviales distales de granulometría fina (Taneciense) que quedaron recubiertos por una delgada cuña marina (Ilerdiense). Encima existen materiales aluviales distales de granulometría fina que pasan gradualmente a otros de granulometría gruesa, que en su parte superior muestran intercalaciones de areniscas y carbonatos con Nummulites y Assilina (Luteciense). Posteriormente, se depositaron lutitas de offshore que soportaron la progradación de materiales arenosos costeros. En la parte central de la cuenca siguió la acumulación de lutitas (Bartoniense) que a su vez fueron afectadas por progradaciones deltaicas en los sectores meridionales y septentrionales. A techo de algunos cuerpos deltaicos se depositaron litosomas arrecifales carbonatados. Sobre una discontinuidad sedimentaria aparece una acumulación compleja de lutitas, areniscas, evaporitas y carbonatos donde se hallan los nuevos yacimientos de peces fósiles (Priaboniense). Entre los especímenes se han identificado algunos Clupeidos, Percofórmidos y Synodontidos que representan los últimos episodios de la sedimentación marina en la zona durante el Eoceno The Plana de Vic is located towards the NE of the Ebro Basin and is mainly characterized by a thick pile of marine sediments that accumulated along the Palaeogene. Overlying a Palaeozoic basement and a marked unconformity are fine-grained non-marine materials (Thanetian), which are covered by the accumulation of a thin marine wedge (Ilerdian). These marine materials were subsequently overlain by fine- and coarse-grained alluvial deposits. Towards the upper part of these alluvial deposits are sandstones and limestones with Nummulites and Assilina. Thereafter, lutitic materials deposited offshore were covered by the prograding coastal sandy materials. In the central part of the basin the accumulation of offshore lutites continued (Bartonian). These lutites were affected by the southwards and northwards deltaic progradations. Limestonedominated reefs were deposited over the deltaic bodies. On top of the sedimentary unconformity is a complex accumulation of lutites, sandstones, evaporites and limestones (Terminal complex) containing the remains of the fossilized fish (Priabonian). Some specimens of Clupeids, Percoformids and Synodonts represent the last episodes of the Eocene marine sedimentation in the study area

According to its original definition, the Artes Formation is formed by the ensemble of continental, red mudstones and sandstones interbedded with conglomerates resting on top of the marine deposits of the Bartonian to Priabonian Santa Maria Croup. However, detailed mapping clearly shows that those marine rocks are laterally equivalent to distal alluvial fan facies of the "Artes type". On the basis of our present sedimentological knowledge these facies can not be differentiated from those forming the Artes Formation sensu stricto .Therefore, we propose a new definition for the entire formation that includes its subdivision into two members

A charophyte biozonation of the Paleogene (Thanetian-Chattian) sequences of the Eastern Ebro Basin (NE Spain) is proposed. This biozonation has been based on an intensive sampling carried out on well correlated sections which included, in some cases, fossil mammal localities. Bothfacts haveresultedin agood chronostratigraphic control of the biozonation. One of the most noticeable contributions from this local point of view is the characterization of the Ilerdian in the continental Ebro Basin sequences by the Maedleriella lavocati biozone. Although in afirst approach this biozonation is intended to be local the new data in the Eastern Ebro Basin have enlarged the ranges of some widespread charophyte index species. These changes in the charophyte sp&ies ranges has led to suggest some remarkable modifications of the preexistin~ Riveline' s (1986) charophyte biozonationfor western Europe: 1) TheN. (T. ) thaleri biozone siaried in the Ilerdian and not in the Cuisian. 2) The definition of new Late Eocene (S. labellata) and Late Oligocene (H. lagenalis) biozones. 3) The enlargement of the range of severa1 species which has resulted in suppressionof the Chara notata biozone and in redefinition of Chara microcera, St. pinguis, St. vectensis and Sr. berdotensis biozones. From apaleogeographic point of view the global percentages of pluricontinental, european and iberian species of the Paleogene Eastern Ebro Basin charophyte record suggest some kind of isolation of the charophyte populations in NE Iberia. This isolation could be enhanced by paleogeographic constraints during Bartonian and Latest Priabonian to Stampian transition.

[ES] En el sector suroriental de la Cuenca del Ebro, la inclinación paleomagnética obtenida en las sucesiones aluviales oligocenas es considerablemente menor que la esperable, si se considera la paleolatitud de referencia calculada para esa región durante el Oligoceno. Este error de inclinación puede deberse a diversos factores, como el control hidrodinámica de las partículas magnéticas en el medio deposicional, la compactación diferencial del sedimento durante el enterramiento, o bien a la deformación tectónica. Este trabajo se ha centrado en su estudio en dos sucesiones dominantemente aluviales, donde previamente se había establecido su magnetoestratigrafia. Las litofacies aluviales y lacustres estudiadas se han agrupado en cinco grupos: areniscas grises, areniscas rojas y versicolores, limos rojos, lutitas rojas y calizas. Se ha demostrado la existencia de una correlación entre la abundancia de filosilicatos y el error de inclinación. De esta manera, las litofacies con un bajo porcentaje de filosilicatos (calizas y areniscas grises) presentan errores de unos 5", estadisticarnente no significativos, con respecto a la inclinación de referencia. Por el contrario, en materiales con un porcentaje más elevado de filosilicatos (limos y arcillas) el error puede llegar a los 25". Este hecho no tiene repercusión en la interpretación de las polaridades magnéticas, pero si en las reconstmcciones palinspásticas y paleogeográficas basadas en los cálculos de paleolatitudes a partir de las paleoinclinaciones. Los resultados obtenidos demuestran la necesidad de cautela en la propuesta de conclusiones basadas exclusivamente en este tipo de información., [EN] Alluvial red-beds of two Oligocene succesions in the Southeastem Ebro Basin (Southem Pyrenean foreland, NE Spain) show inclination shallowing, taking into account the reference Oligocene palaeolatitude expected for this region. This fact is interpreted to reflect an inclination error due to either these factors: hydrodynamic control of magnetic particles in the depositional environment, differential compaction of sediment during burial and tectonic deformation. The studied lithofacies are split into five groups: gray sandstones, red sandstones, red siltstones, red mudstones and limestones. A strong positive correlation between the relative amount of phyllosilicates and the magnitude of the inclination error has been established. Lithofacies with low percentage of phyllosilicates (limestones and gray sandstones) display a statistically not significant error of 5" with respect to the magnetic palaeofield inclination, whereas the sediments with a higher phyllosilicate content (siltstones and mudstones) show significant errors of up to 25". This observation has not a major consequence for the interpretation of the magnetic polarity but is crucial for palaeogeographic and palinspastic reconstmctions based on palaeolatitudinal data. The obtained results in this study highlight that the interpretation of paleolatitude based on paleomagnetic data is sometimes not straightfonvard and it requires a detailed evaluation of the rock magnetic parameters (AMS in particular) to reveal the presence of such inclination deflection., Los autores expresan su agradecimiento a M. Inglés por los datos aportados sobre la mineralogía de las lutitas y a M. Steiner por la identificación de minerales magnéticos al microscopio y por las facilidades dadas en su laboratorio durante la estancia del primero de los firmantes. Igualmente agradecen los comentarios aportados por M. Garcés y R. Molina que han contribuido a mejorar este trabajo, que se encuadra en los proyectos de la CICYT no PB-97-0882-C03-01 y de la DGES no. PB96-0815 del Ministerio de Educación y Cultura. También fue en parte financiado por el "Grup de Recerca de Qualitat SGR 97-73, del Comissionat per Universitats i recerca de la Generalitat de Catalunya (Geodinamica i Analisi de Conques). X. Barbera ha disfrutado de una beca doctoral FPI del Ministerio de Educación y Ciencia y de las ayudas de viaje relacionadas con la misma.