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El proyecto Geosites, en desarrollo por el grupo de trabajo Global Geosites de la IUGS y patrocinado también por la UNESCO, persigue la elaboración de un inventario global del patrimonio geológico de la Tierra. Este inventario global requiere una metodología sistemática, basada en la selección en cada país de sus contextos geológicos de trascendencia internacional. Estos contextos geológicos o frameworks consisten en eventos temáticos, o en elementos cronológicos o geotectónicos regionales. El segundo paso en esta metodología es la selección de los lugares más valiosos y representativos de estos contextos geológicos, denominados geosites (geotopos o lugares de interés geológico). Afortunadamente la diversidad geológica española suministra un gran número de contextos geológicos con relevancia internacional; además la buena calidad de los afloramientos (debida a causas climáticas y topográficas) permitirá la selección de geotopos ilustrativos. En esta comunicación se presenta un listado de los contextos geológicos españoles elaborado por consenso. Se ha preparado siguiendo la metodología del Proyecto Geosites sin tener en cuenta el Inventario Nacional de Puntos de Interés Geológico que está en ejecución y cubre alrededor del 40% del territorio español. El IGME preparó una lista preliminar que fue enviada a todos los departamentos universitarios de Ciencias Geológicas, Minas y centros públicos de investigación, para su análisis, discusión y mejora. Como resultado de esta encuesta se han seleccionado 20 frameworks o contextos geológicos que constituyen la primera aportación española al proyecto Geosites., The Geosites project, initiated by the IUGS Global Geosites Working Group and also supported by UNESCO, aims to produce a global inventory of the Earth’s geological heritage. This global inventory requires a systematic methodology, which is based on the selection of geological frameworks with international significance, in every country. These frameworks are topic events, time or regional geotectonic elements, etc. The second step of this methodology is the selection of the most valuable and representative sites of these geological frameworks (geosites). Fortunately, the geological diversity of Spain provides a great number of frameworks with global significance; in addition, the high quality of outcrops (due to topographic and climatic reasons) will allow the selection of illustrative geosites. In this paper a list of Spanish geological frameworks set by consensus is presented. It was prepared following the Geosites Project methodology without taking into account the National Inventory of Geosites, which is in progress and covers a 40% of the Spanish territory. The IGME (Geological Survey of Spain) composed a preliminarg list, which was sent to all the University Departaments of Geology, Mining Schools and Research Centers, for its analysis, discussion and improvement. The result of this request was the selection of 20 “frameworks”, which is the first Spanish contribution to the Geosites Project., Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

[EN] An integrated study including magnetostratigraphy, larger benthic foraminifera and calcareous nannofossil biostratigraphy is presented herein. This work was performed in shallow marine siliciclastics rich in larger foraminifera, around the Ypresian/Lutetian boundary in the Ésera valley (South-Central Pyrenees). Although the calcareous nannofossil content in the studied interval is low, not allowing a precise Y/L boundary to be recognised, the taxa found are enough to support the chronostratigraphic attribution. Data obtained in the Ésera valley section has improved the knowledge of larger benthic foraminifera (Nummulites and Assilina) distribution through chron C21. SBZ 11 to SBZ 12 transition took place at the lowermost C21r, as shown in previous works. SBZ 12 assemblages extend into C21n, where the SBZ 12 to SBZ 13 boundary occurs. These data, obtained in shallow marine siliciclastic facies, with in situ fauna, results in a shift of the SBZ 12/SBZ 13 boundary to the Lower Lutetian, younger than previously believed. Accordingly, the Ypresian/Lutetian boundary occurs in SBZ 12.

[EN] Despite the large number of magnetostratigraphic studies in the South Pyrenean Basin aiming to calibrate the basin chronostratigraphy and the biostratigraphic scales, the South Eastern Jaca Basin remains unexplored from this perspective, and its relation with the Ainsa Basin is not fully understood. In this work we contribute with new magnetostratigraphic data from the 950m thick Las Bellostas section, located in the northern hinge of the Balzes anticline. Well-proven primary signal (positive fold test and two pseudo-antiparallel polarities) supported by numerous primary data in the surroundings allow us building a reliable local polarity sequence of eight magnetozones (from R1 to N4). Additionally, seven new biostratigraphic samples (Nummulites and Assilina) in the lower part of the section (marine environment) allows tightening the section to the Geomagnetic Polarity Time Scale (GPTS) and proposing a refined age model for the southeastern Jaca Basin. The section starts in the Boltaña Fm., of Cuisian age (Shallow Benthic Zone, SBZ11), is followed by a sedimentary gap from C22n to C20n as witnessed by biostratigraphic data (SBZ11 underneath the hiatus and SBZ16 just atop). The deltaic Sobrarbe Fm can be tracked until the C19n (Late Lutetian). From this point (200m) until the top of the section (950m), at least, the entire C18n chron can be recognized within the molassic Campodarbe Fm (C18n.2n-C18n.1r and C18n.1n) (Bartonian) equivalent to the West to the prodeltaic Arguis marls Fm. The Middle Cusian (SBZ11) to Middle Lutetian (SBZ15) stratigraphic hiatus is, in part, enhanced by the structural position at the hinge of the Balzes anticline. These new chronostratigraphic constraints help refining the W-E and N-S stratigraphic relationships in the eastern Jaca Basin and in the Ainsa Basin. This section also allows us to accurately refine the kinematics of the rotational activity in the eastern External Sierras. The important difference in magnetic declination alon

CRUE-CSIC (Acuerdos Transformativos 2022), The record of brachiopods in the Lower Toarcian of the Balearic Islands is described after a reassessment of previous works and new samplings in the Tramuntana Range of Mallorca. The recognized species have been assimilated to the assemblages described in the Iberian Range in the Tenuicostatum and Serpentinum biozones. Moreover, a detailed comparison with other Western Tethys basins and the study of the dispersion of the brachiopod faunas in relation with the Early Toarcian Oceanic Anoxic Event, allow to refine the paleobiogeographic relationship of the Balearic brachiopods. They belong to the Euro-Boreal Province of brachiopods in the Tenuicostatum Biochron and correspond to the”Spanish Fauna” that emerged after the deep paleobiogeographic disruption that took place at the base of Serpentinum Biochron. The occurrence of Prionorhynchia msougari Rousselle in the Serpentinum Zone of Mallorca indicates that, within this last assemblage, there would be a closer connection between the Balearic region and the southern margin of the Tethys (Betic and North African basins) than with the northern margin (Eastern Iberian Platform System and Eastern Pyrenees). This paleobiogeographic conclusion is consistent with the supposed position of the Balearic area in the Early Toarcian, on the southeastern margin of Iberia and near the Alboran and Kabylian margins., Ministerio de Ciencia e Innovación (MICINN), Universidad Complutense de Madrid, Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

Burial diagenesis is one of the main mechanisms claimed for explaining pervasive remagnetizations in sedimentary basins and orogenic wedges worldwide. It involves authigenic formation (e.g. chemical remagnetization) of magnetic minerals in response to enhanced temperature conditions at deep basinal positions. Key questions about the kinetics of this process in natural cases remain unsolved because most of the best-documented cases occurred during long-lasting magnetic superchrons. The Western Pyrenees display a dual polarity record of a burial remagnetization affecting the deepest part of the Eocene Jaca turbiditic basin and its underlying units. A preliminary study of 49 sites distributed along three cross sections reveals that postfolding (remagnetized) ChRM directions are found within the lowermost part of the studied sedimentary pile, which is affected by cleavage, in such a way that ChRM unblocking temperatures increase as a function of depth. Noteworthy, this remagnetization is associated with hysteresis data typical for chemical remagnetizations (samples falling mainly within the SP+SD+MD mixing line in the Day plot), and displays up to five different polarity zones that are consistent along strike in the three studied cross sections. Prefolding ChRM directions are found, in contrast, in the overlying sequence above the cleavage domain. We intend to carry out a detailed, multidisciplinary study of this remagnetization in the framework of the recently funded UKRIA4D project, that will integrate: A) a full characterization of the remagnetization front combining paleomagnetic and rock-magnetic data; B) characterization of the burial conditions based on SEM and TEM observations of mineral assemblages and temperature estimates from RAMAN spectroscopy on carbonaceous material; and C) magneto-biostratigraphic dating of the 7 km-thick overlying sedimentary sequence. Integration of these data will allow establishment of the burial conditions that led to the observed r

This chapter deals with the two Alpine Foreland Basins of the Iberian Peninsula. The first part of the chapter refers to the South Pyrenean Foreland Basin and its westward prolongation, the Basque–Cantabrian Paleogene Basin. It includes: (1) the introductory concepts about the basin extend, margins, sedimentary systems, basin evolution and segmentation, and terminology; (2) the impact of PETM; (3) the stratigraphy and geometry of foreland carbonate margin with special emphasis on the recent advances in its chronology and evolution, (4) the stratigraphy and geometry of the siliciclastic basin fill reflecting the recent advances in chronology and provenance; (5) and finally, discusses on the sedimentary imprints of the orogenic evolution. The second part of this chapter is focused on the Guadalquivir Basin, which developed in the southern Iberian margin at the foreland of the Betic orogenic front during the last stages of foreland basin development. An introduction to the overall geology of the basin is given before an updated view on the chronostratigraphy of its sedimentary infill is outlined. Such an updated framework provides the basis for disentangling the geodynamic processes that are encoded in the sedimentary record of the basin.

[EN] Anisotropic magnetic susceptibility (AMS) analysis of 1454 samples evenly distributed along an 1800 m section in the South Pyrenean Zone is presented. The sampled rocks are pre- and syn-tectonic limestones, marls and sandstones of Ypresian-Lutetian age. They are weakly deformed rocks sampled from both limbs of the N–S trending Boltaña Anticline (oblique to the WNW–ESE main Pyrenean trend). Rock magnetism analyses, including low temperature and high field magnetic susceptibility measurements confirm a dominant paramagnetic signal and hence allow the interpretation of AMS in terms of preferred rock fabric or finite strain orientation. Therefore, this study was focused on obtaining an independent kinematic information from a vast set of AMS data from particular structural positions. The three directional maxima for the maximum axis of the magnetic ellipsoid (KMAX, magnetic lineation) can be tentatively related to major tectonic events in the Central Pyrenees. A first stage (recording a N–S magnetic lineation) is related to an oblique ramp of the Cotiella Thrust, emplaced during Ypresian times. A pseudo-progressive variation turns into a second stage (linked to a NW–SE KMAX orientation maximum) that can be related to Pyrenean compression. Both stages witness a far-field imprint of active structures on the foreland sediments. Once the Boltaña Anticline was nucleated (during the Lutetian), a predominant, more constant NW–SE trend is observed, this near-field magnetic fabric being the only lineation imprinted in the rocks. A final stage arrived in the course of vertical axis rotation during the Late Lutetian-Bartonian. This latest event was responsible for the present configuration of the Boltaña Anticline (N–S).

[EN] In this work we present AMS results obtained from several profiles in the Lutetian, carbon-ate-slope sequence located in the eastern limb of the Boltaña anticline. The AMS analyses allow us todefine the deformational events related to the formation of the Boltaña anticline and its progressiverotation during Eocene (Late Lutetian) times, acting as a passive marker of the deformation, after a veryearly record of LPS during diagenesis.

We report the structural geometry and facies architecture of a small diapir-related carbonate-dominated basin from the Jurassic rift of the Moroccan High Atlas. The Azag minibasin is a lozenge-shaped depocenter completely enclosed by tectonic boundaries that we interpret as welds after former salt anticlines or salt walls. The exposed ca. 3000 m-thick infill of the Azag minibasin is asymmetric; layers are tilted to the W defining a rollover geometry. Areally-restricted sedimentary discontinuities and wedges of growth strata near the basin margins indicate sedimentation contemporaneous with diapiric rise of a Triassic ductile layer. Facies evolution through the basin reflects local accommodation by salt withdrawal and regional events in the High Atlas rift. The early basin infill in the Sinemurian and Pliensbachian shows thickness variations indicative of low-amplitude halokinetic movements, with reduced exposed thicknesses compared to surrounding areas. The exposed Toarcian and Aalenian deposits are also reduced in thickness compared to areas outside the basin. Subsidence increased dramatically in the Bajocian-early Bathonian (?), the main phase of downbuilding, when over 2600 m of carbonates and shales accumulated at a rate > 0.5 mm/a in the depocentral area of the minibasin governed by W-directed salt expulsion. The stratigraphic units distinguished often show maximum thicknesses and deeper facies in the depocentral area, and rapidly change to shallower facies at the basin margins. The Bajocian carbonate facies assemblage of the minibasin include: reservoir facies as microbialite-coral reefs in the basin margins (formed during periods of strong diapir inflation and bathymetric relief), basin-expansive oolite bars (formed during episodes of subdued relief), and organic-rich, dark lime mudstones and shales that show source-rock characteristics. The Azag basin is a good analog for the exploration of salt-related carbonate plays in rifts and continental margins where

This study deals with how vertical-axis rotations are accommodated in thrust fronts. Studies on the rotational kinematics of fold and thrust belts are limited owing to the scarcity of the record of syntectonic rocks and other data required for 4D reconstruction approaches. We studied the Balzes anticline, a 17-km long, thrust-related, arc-shaped anticline with dense paleomagnetic sampling (75 sites) to unravel the origin of its curvature (about 50° of arc in map view). The availability of both synfolding and synrotational indicators enables us to decipher the complete kinematic history of the fold. Reliable paleomagnetic data (more than 500 specimens and about 1000 measurements) were obtained from Ypresian to Priabonian rocks, typically with six demagnetization steps. The ChRM is unblocked between 420 and 575 °C in most samples (85%), and at 675 °C in the others. The primary direction displays two polarities and passes the fold test. Vertical axis rotation values for the structure range from non-significant up to > 80° clockwise. A strike vs. rotation diagram clearly relates this variability to the fold curvature (VAR = − 46° + 0.5 ∗ TREND [R = 0.97]) and reveals the addition of primary and secondary curvatures. The original (primary) curvature is related to the emplacement of the thrust sheet underlying the Balzes anticline; it shows an obliquity of approximately 15° with respect to the expected Pyrenean trend. Progressive unconformity in the field (Santa Marina site) provides a record of a Middle–Late Lutetian major folding event. The detailed analysis of the synrotational sedimentary record together with accurate temporal calibration based on previous magnetostratigraphic data allows us to date the rotation stage as Lutetian–Bartonian and to estimate the rotation velocity of the Balzes anticline to have been about 5.2°/Ma, both in agreement with previously published observations for the South Pyrenean front.

Complex kinematic scenarios in fold-and-thrust belts often produce superposed and non-coaxial folding. Interpretation of primary linear indicators must be based on a careful restoration to the undeformed stage following the reverse order of the deformation events. Therefore, sequential restoration to the ancient coordinate system is of key importance to obtain reliable kinematic interpretations using paleomagnetic data. In this paper, a new paleomagnetic study in the western flank of the Boltaña anticline (Southern Pyrenees) illustrates a case study of a complex tectonic setting having superposed, non-coaxial folds. The first stage of NW–SE folding linked to the oblique Boltaña anticline took place during Lutetian times. The second stage was linked to the vertical axis rotation and placed the Boltaña anticline in its present-day N–S configuration. Our data support a long-lasting Lutetian to Priabonian period with main rotational activity during the Bartonian–Priabonian; other authors support a VAR coeval with anticlinal growth. The third stage resulted in southwards tilting related to the emplacement of the N120E striking Guarga basement thrust (Oligocene–Early Miocene). Based on this deformational history, a sequential restoration was applied and compared with the classic bedding correction. At the site scale, single bedding correction gives errors ranging between 31° and − 31° in the estimation of vertical axis rotations. At the locality scale, in sites grouped in three folds (from W to E Arbella, Planillo and San Felizes), the bedding corrected data display rotation values in accordance with those found in the Ainsa Basin by other authors. Sequential restoration (based on the afore-mentioned evolution in three-steps) improves both some locality-means and the internal consistency of the data. Therefore, reasonably-constrained sequential restoration becomes essential to reconstruct the actual history of superposed folding areas.

La zona de Jánovas presenta una superposición de pliegues resultado de eventos no coaxiales. La corrección de capa de los vectores paleomagnéticos en el sistema de coordenadas original ha sido realizada de modo secuencial, siguiendo el orden inverso de los eventos de deformación, y comparada con la clásica corrección de capa. La restitución secuencial da lugar a medias mejor agrupadas, constituyendo una puerta abierta a la reconstrucción en zonas con superposición de pliegues. Por medio de las orientaciones obtenidas de la restitución secuencial, hemos determinado un modelo de edad para la zona de Jánovas, estableciéndose, una tasa de acumulación creciente, de acuerdo con la continentalización de la cuenca hacia el Bartoniense. El modelo de rotación obtenido presenta amplios errores debido a la presencia de intervalos heterogéneos de muestreo, evidenciando la necesidad de densificar el muestreo entre 50 y 45 Ma, para afinar la tendencia de rotación y principalmente entre 38 y 35 Ma donde se produciría el final de la rotación horaria del anticlinal de Boltaña

This study deals with how vertical-axis rotations are accommodated in thrust fronts. Studies on the rotational kinematics of fold and thrust belts are limited owing to the scarcity of the record of syntectonic rocks and other data required for 4D reconstruction approaches. We studied the Balzes anticline, a 17-km long, thrust-related, arc-shaped anticline with dense paleomagnetic sampling (75 sites) to unravel the origin of its curvature (about 50° of arc in map view). The availability of both synfolding and synrotational indicators enables us to decipher the complete kinematic history of the fold. Reliable paleomagnetic data (more than 500 specimens and about 1000 measurements) were obtained from Ypresian to Priabonian rocks, typically with six demagnetization steps. The ChRM is unblocked between 420 and 575 °C in most samples (85%), and at 675 °C in the others. The primary direction displays two polarities and passes the fold test. Vertical axis rotation values for the structure range from non-significant up to > 80° clockwise. A strike vs. rotation diagram clearly relates this variability to the fold curvature (VAR = − 46° + 0.5 ∗ TREND [R = 0.97]) and reveals the addition of primary and secondary curvatures. The original (primary) curvature is related to the emplacement of the thrust sheet underlying the Balzes anticline; it shows an obliquity of approximately 15° with respect to the expected Pyrenean trend. Progressive unconformity in the field (Santa Marina site) provides a record of a Middle–Late Lutetian major folding event. The detailed analysis of the synrotational sedimentary record together with accurate temporal calibration based on previous magnetostratigraphic data allows us to date the rotation stage as Lutetian–Bartonian and to estimate the rotation velocity of the Balzes anticline to have been about 5.2°/Ma, both in agreement with previously published observations for the South Pyrenean front.

[EN] Complex kinematic scenarios in fold-and-thrust belts often produce superposed and non-coaxial folding. Interpretation of primary linear indicators must be based on a careful restoration to the undeformed stage following the reverse order of the deformation events. Therefore, sequential restoration to the ancient coordinate system is of key importance to obtain reliable kinematic interpretations using paleomagnetic data. In this paper, a new paleomagnetic study in the western flank of the Boltaña anticline (Southern Pyrenees) illustrates a case study of a complex tectonic setting having superposed, non-coaxial folds. The first stage of NW–SE folding linked to the oblique Boltaña anticline took place during Lutetian times. The second stage was linked to the vertical axis rotation and placed the Boltaña anticline in its present-day N–S configuration. Our data support a long-lasting Lutetian to Priabonian period with main rotational activity during the Bartonian–Priabonian; other authors support a VAR coeval with anticlinal growth. The third stage resulted in southwards tilting related to the emplacement of the N120E striking Guarga basement thrust (Oligocene–Early Miocene). Based on this deformational history, a sequential restoration was applied and compared with the classic bedding correction. At the site scale, single bedding correction gives errors ranging between 31° and − 31° in the estimation of vertical axis rotations. At the locality scale, in sites grouped in three folds (from W to E Arbella, Planillo and San Felizes), the bedding corrected data display rotation values in accordance with those found in the Ainsa Basin by other authors. Sequential restoration (based on the afore-mentioned evolution in three-steps) improves both some locality-means and the internal consistency of the data. Therefore, reasonably-constrained sequential restoration becomes essential to reconstruct the actual history of superposed folding areas.

The Ainsa Basin (south-central Pyrenees) is an exceptional example of a syntectonic foreland basin where structures oblique to the Pyrenean trend are well preserved. The absence of a complete chronostratigraphic frame motivated us to perform a detailed magnetostratigraphic study in the Ainsa Basin, including the shallow-marine–continental transition. Three sections covering almost the entire Eocene sedimentary fill were sampled (Ara, Coscollar, and Mondot), covering 2450 m of the sedimentary pile, with more than 1000 demagnetized specimens (sample spacing of 2.7 m). Data from previous magnetostratigraphic studies (Eripol section) allow us to complete the Eocene record with an 840-m-long profile within the Bartonian–Priabonian interval overlying the sampled sequence. Characteristic remanent magnetization (ChRM) directions were effectively isolated between 300 and 500 °C. Magnetite is the main magnetic carrier, with variable iron sulfide content and occasional hematite. Fold tests indicate a prefolding magnetization. Biostratigraphy based on shallow benthic foraminifera (15 localities) and a locality with abundant charophyte gyrogonites help to constrain the local magnetostratigraphic record (20 reversals) between the early Ilerdian and the middle Priabonian. A global correlation based on a magnetostratigraphic composite section derived from this work allows us to propose a complete chronostratigraphic frame for the Ainsa Basin infill between 55 and 45 Ma. Accumulation rates range from 2 to 53 cm/k.y., responding to retrogradational to progradational features during the early Lutetian, and a progressive increase from the middle Lutetian onward related to overall continentalization of the basin. Westward migration of subsidence is associated with progressively younger synsedimentary structures nucleating westward of the older ones in the South Pyrenean Basin

In this paper, we present a chronostratigraphic calibration of the shallow benthic zones (SBZs) of larger foraminifera during Lutetian times based on new magnetostratigraphic data (Isuela section) and two new densely sampled biostratigraphic sections (Isuela and Gabardiella). These sections are located in the External Sierras (Southern Pyrenees) and represent an ideal location to avoid previous chronostratigraphic problems. 1) They belong to a shallow carbonate shelf environment with abundant larger foraminifera, which ensure the reliability of SBZ data. 2) The time span covers almost the entire Lutetian interval. 3) The profiles are sufficiently long to establish trustworthy local scales, both the SBZs (520 m and 760 m in Isuela and Gabardiella respectively) and the paleomagnetic local polarity sequence (LPS) (520 m). 4) The excellent outcropping conditions also permit a detailed paleomagnetic and biostratigraphic sampling to be performed. The LPS at the Isuela section was built after sampling every 2.6 m. In total, more than 359 samples were thermal (244) and alternating field (115) demagnetized. Characteristic remanent magnetization (ChRM) usually dropped at 560 °C. Only 43% the samples (359 demagnetizations) gave reliable directions (high quality) for the LPS. A further short section (Gas line) was also cored (38 samples in 90 m) to obtain more detailed data for the upper part of the section. At the Isuela section, the results allow three pairs of trustable magnetozones to be assembled within the Lutetian. A further 255 samples were taken for biostratigraphic purposes, 55 sites at the Isuela and 52 at the Gabardiella sections being determinant. This density enabled a thorough study of changes in fossil associations to be performed. Assuming a constant accumulation rate within the chron boundaries, absolute ages have been estimated for the biostratigraphic boundaries. Combining all these data allows the previous calibration of SBZ during Lutetian times in the geo

Despite the large amount of paleomagnetic and structural studies on fold and thrust belts, many key questions about rotational kinematics remain unsolved (pace of rotation, subsequent accommodation of the hanging wall, etc.). Excellent exposure conditions and syntectonic sedimentation related to the growth of oblique structures in the Southern Pyrenees allow an accurate investigation that sheds light on the rotational kinematics of thrust systems. Fifty-nine paleomagnetic sites (819 specimens) are homogeneously distributed in both limbs along the marine and continental sedimentary sequences contemporary with the uplift of the Boltaña anticline and its post-folding evolution. They indicate a clockwise rotation of about 52 during Ypresian to Priabonian times. Primary, stable (350 -580 C), pre-folding magnetization in the Eocene rocks is attested by a positive fold test and the antipodality proof, with magnetite and iron sulphide traces as magnetic carriers. Rotation velocity fits a logarithmic model and shows a low rate during the Ilerdian-Middle Lutetian interval (ca. 1 /m.y.) and much higher (up to 10 /m.y.) in the Late Lutetian-Priabonian interval. Most of the clockwise rotation of the Boltaña anticline can therefore be constrained within the 42e35 M.a. interval (partially post-folding), indicating a period of strong differential displacement in the southern Pyrenean Zone, probably related to the emplacement of the underlying External Sierras thrust sheets (Tozal-Alcanadre).

[ES] En este trabajo se pone de manifiesto la existencia de un complejo sistema de canales medio-oceánicos en la llanura abisal de Vizcaya a partir de la información batimétrica, de reflectividad y de perfiles sísmicos de muy alta resolución obtenidos desde 2001 en el marco del proyecto de Investigación Científica de la ZEEE. Los resultados preliminares del estudio morfológico revelan la presencia de dos sistemas de canales submarinos, con una longitud total de unos 700 km y a una profundidad alrededor de 5.000 m. El desarrollo de estos sistemas tiene su origen al norte en el sistema turbidítico Céltico-Armoricano y al este en el sistema turbidítico de Cap Ferret. Los sistemas de canales se unen frente a los altos estructurales de Charcot. Hacia el sur se diferencia un sistema principal, con canales erosivos y tramos rectilíneos bordeando el Alto de A Coruña, y un sistema secundario, con mayor sinuosidad y agradación sedimentaria en la mayoría de los canales. Todos ellos convergen en un estrechamiento morfoestructural denominado Theta Gap que da paso a la llanura abisal de Iberia. Este sistema de desagüe submarino está probablemente vinculado tanto a cambios climáticos y eustáticos, como a un fuerte control estructural lo cual ha condicionado la localización, el tipo flujo, la erosión/depósito y su reciente jerarquización, [EN] The Biscay abyssal plain has been analyzed based on bathymetry data and very high resolution seismic profiles obtained since 2001 under the scientific research project of the ZEEE. Preliminary results of the morpho-sedimentary study reveal the presence of two deep-sea channel systems named Cap Ferret and Armorican, with a total length of 700 km and around 5,000 m of water depth. The development of these systems has its origin south of the Celtic-Armorican and west of Cap Ferret turbiditic systems, both joining at the southern zone of the Charcot highs. At this part a main system, with straight stretches erosive channels along the A Coruña High, and a secondary system, characterised by more sinuous and repositional channels, are developed. They all converge towards the Theta Gap, connecting the Biscay and Iberia abyssal plains. The genesis of the deep-sea channel systems is likely linked to the continuation of turbiditic processes generated in the adjacent continental margins, but amplified by the action of bottom currents. Their recent development appear to be controlled by climatic and eustatic fluctuations, as well as a strong structural control, which has conditioned the location, type of flow, erosion / deposition and its recent ranking

Multichannel and high resolution seismic profiles from the central Scotia Sea and northern Weddell Sea show a sequence of seismic units interpreted to be the result of high-energy bottom currents. The seismic character of the units is indicative of active bottom flows, which developed extensive drifts under the influence of the Weddell Sea Bottom Water (WSBW) and the Antarctic Circumpolar Current (ACC). The opening of the connection between Jane Basin and the Scotia Sea is marked by a major regional unconformity that recorded a reorganization of bottom flows. The uppermost deposits are characterized by intensified bottom currents, which may reflect increased production of WSBW.

Multichannel and high-resolution seismic profiles complemented with swath bathymetry show a variety of contourite deposits in the northern Weddell Sea resulting from the interaction between bottom currents and the seafloor physiography. Seven types of contourite drifts are identified based on the seismic signature, reflector configuration and geometry of the depositional bodies. Giant elongated–mounded drifts are widespread in the area and associated with major channelized contour currents that flow at the base of large ridges. Thick basement/tectonic drifts result from the seafloor disruptions of the currents caused by the irregularities of the near-surface basement morphology. Sheeted drifts occur under the main core of the Weddell Gyre and also in areas of the abyssal plain away from the main flows. Various types of drifts in-fill depressions or are plastered against steep bathymetric ridges that intersect contour currents. The regional distribution of the drifts is mainly controlled by the physiography of the basin and the confined or unconfined nature of the bottom-current flows. The northern Weddell Sea is a region dominated by contourite processes and thus provides an area to compare contourite drifts with turbidite systems. The giant elongated–mounded drifts have a net asymmetry of the body, in contrast to turbidite channel–levee complexes that develop levees on each side of an axial turbidite channel. The basement/tectonic drifts prograde parallel to the main flow and are plastered following the irregularities of the basement unlike turbidite deposits. Other drifts, in contrast, show internal reflector characteristics similar to turbidite systems, such as the sheeted drifts. In these cases, however, the associations of turbidite and drift deposits are different. The giant elongate-mounded drifts are stacked along the margins and elongate or transverse drift sequences are observed in the basin centre of confined basins. In the unconfined setting, the drifts

In the southeastern Ebro Foreland Basin, the marine deposits of Lutetian and Bartonian age show excellent outcrop conditions, with a great lateral and horizontal continuity of lithostratigraphic units. In addition, the rich fossil record -mainly larger foraminifers-, provides iostratigraphic data of regional relevance for the whole Paleogene Pyrenean Basin, that can be used for the Middle Eocene biocorrelation of the western Tethys. This contribution is a sedimentary and biostratigraphic synthesis of the basic outcrops and sections of the Lutetian and Bartonian marine and transitional deposits in the southeastern sector of the Ebro Foreland Basin.

The lateral ending of the South Shetland Trench is analysed on the basis of swath bathymetry and multichannel seismic profiles in order to establish the tectonic and stratigraphic features of the transition from an northeastward active to a southwestward passive margin style. This trench is associated with a lithospheric-scale thrust accommodating the internal deformation in the Antarctic Plate and its lateral end represents the tip-line of this thrust. The evolutionary model deduced from the structures and the stratigraphic record includes a first stage with a compressional deformation, predating the end of the subduction in the southwestern part of the study area that produced reverse faults in the oceanic crust during the Tortonian. The second stage occurred during the Messinian and includes distributed compressional deformation around the tip-line of the basal detachment, originating a high at the base of the slope and the collapse of the now inactive accretionary prism of the passive margin. The initial subduction of the high at the base of the slope induced the deformation of the accretionary prism and the formation of another high in the shelf—the Shelf Transition High. The third stage, from the Early Pliocene to the present-day, includes the active compressional deformation of the shelf and the base-of-slope around the tip-line of the basal detachment, while extensional deformations are active in the outer swell of the trench.

This paper reports a comparative study of the use of palaeohydrological and hydrological techniques to estimate magnitude and frequency of floods applied to two high-gradient, small catchments located in the Spanish Central Pyrenees: the Arás basin, 18.6 km2; the Montardit basin, 15.2 km2. Palaeohydrological (palaeoflood) techniques, based on palaeostage indicators and the application of both Manning's equation and critical flow equation, were used to estimate discharge values corresponding to seven cross-sections of the Montardit stream. This method yielded discharges ranging from 7 to 112 m3 s−1. Palaeoflood and historical flood analyses indicated a greater frequency of high magnitude events for both the Arás and Montardit basins than suggested by the application of two different methodologies based on precipitation data (the rational and the unit hydrograph methods). The 1996 Arás basin flood was modelled using the unit hydrograph method, with most reliable results (217 m3 s−1) obtained using a semidistributed basin model. For small, ungauged mountain basins, palaeoflood reconstruction provides an excellent tool to obtain past flood discharges on which to base the calibration of parameters (e.g. runoff threshold) used in rainfall–runoff methods. It is proposed that the combined results of long-term flood record analysis (based on palaeoflood and historical data) and of standard hydrometeorological methods will aid in the assessment of flood risks for application to the design of emergency measures and floodplain management in ungauged mountain streams.

The Portimao canyon, placed in the southern Portugal continental margin, is a good example to study the relationship between the downslope sedimentary transport from the continental shelf to deep basin as well as the a long slope sedimentary transport induced by oceanic contour currents. Submarine canyons are interpretad as a sedimentary pathway between the shelf and the deep basin along the slope. A particular pattern is developed in the Gulf of Cadiz where a complex distribution of canyons, valleys and gulies it seem to be linked to the contourite drifts bodies generated under the influence of the Mediterranean Outflow Waters (MOW) at intermediate deeps. The head of the Portimao canyon occurs near the shelfbreak at a depth of 110 m and its intersection with the contourite drift occurs at intermediate deeps of 700 to WOO m. The sedimentary structure of the canyon walls, infered from the Inflexion of the conturite reflectors into the canyon, as well as the end of the Alvarez Cabral Deep into the Portimao canyon, seems to indicate the role of Portimao canyon as a source of feeding the Horseshoe abisal plain with contour sediments.

New swath bathymetric, multichannel seismic and magnetic data reveal the complexity of the intersection between the extinct West Scotia Ridge (WSR) and the Shackleton Fracture Zone (SFZ), a first-order NW-SE trending high-relief ridge cutting across the Drake Passage. The SFZ is composed of shallow, ridge segments and depressions, largely parallel to the fracture zone with an `en echelon' pattern in plan view. These features are bounded by tectonic lineaments, interpreted as faults. The axial valley of the spreading center intersects the fracture zone in a complex area of deformation, where N120° E lineaments and E–W faults anastomose on both sides of the intersection. The fracture zone developed within an extensional regime, which facilitated the formation of oceanic transverse ridges parallel to the fracture zone and depressions attributed to pull-apart basins, bounded by normal and strike-slip faults. On the multichannel seismic (MCS) profiles, the igneous crust is well stratified, with numerous discontinuous high-amplitude reflectors and many irregular diffractions at the top, and a thicker layer below. The latter has sparse and weak reflectors, although it locally contains strong, dipping reflections. A bright, slightly undulating reflector observed below the spreading center axial valley at about 0.75 s (twt) depth in the igneous crust is interpreted as an indication of the relict axial magma chamber. Deep, high-amplitude subhorizontal and slightly dipping reflections are observed between 1.8 and 3.2 s (twt) below sea floor, but are preferentially located at about 2.8–3.0 s (twt) depth. Where these reflections are more continuous they may represent the Mohorovicic seismic discontinuity. More locally, short (2–3 km long), very high-amplitude reflections observed at 3.6 and 4.3 s (twt) depth below sea floor are attributed to an interlayered upper mantle transition zone. The MCS profiles also show a pattern of regularly spaced, steep-inclined reflectors, which cu

New bathymetric and magnetic anomaly data from the Phoenix Ridge, Antarctica, show that extinction of all three remaining segments occurred at the time of magnetic chron C2A (3.3 ± 0.2 Ma), synchronous with a ridge-trench collision south of the Hero Fracture Zone. This implies that the ultimate cause of extinction was a change in plate boundary forces occasioned by this collision. Spreading rates slowed abruptly at the time of chron C4 (7.8 ± 0.3 Ma), probably as a result of extinction of the West Scotia Ridge, which would have led to an increase in slip rate and transpressional stress across the Shackleton Fracture Zone. Spectacular, high-relief ridges flanking the extinct spreading center, mapped for the first time using multibeam swath bathymetry, are interpreted as a consequence of a reduction in spreading rate, involving a temporary magma oversupply immediately prior to extinction.

[ES] Se describen las unidades litoestratigráficas correspondientes a los materiales jurásicos de la Isla de Mallorca, así como las asociaciones fósiles (ammonites, braquiópodos y microfósiles) que han sido identificadas. Los materiales jurásicos más antiguos tienen características litoestratigráficas similares a las que han sido descritas para otros ámbitos paleogeográficos del Tethys. La primera unidad, denominada Fm. Mal Pas, comprende brechas dolomíticas («carniolas») en las que no se han reconocido fósiles que permitan datarla, por lo que su atribución al Hettangiense se fundamenta en la edad de los materiales infra y suprayacente. A la segunda unidad se le ha denominado Fui. Sóller. Está constituida en su base por materiales carbonáticos organizados en secuencias somenzantes (Mb. Es Barraca), atribuidos al Sinemuriense-Pliensbachiense por su contenido micropaleontológico. Localmente, a techo de estas facies se individualizan margas amarillentas (Mb. Sa Moleta) con fósiles característicos de las Zonas Jamesoni e Ibex del Carixiense. La parte superior de la formación corresponde a materiales siliciclásticos (Mb. Es Racó) que probablemente representan la parte superior del Carixiense., [EN] The lithostratígraphic units and fossil assemblages (ammonites. brachiopods. microfossils) of the Jurassic in the Mallorca Island are described here. The oldest Jurassic sedimentary rocks (Mal Pas Fm.) are similar to the ones described in the Tethys realm. The unit consist of dolomitie breccias («Carniolas») and its stratigraphic position, overlying Norian sediments, suggest a possible Hettangian Age. Follows op the Sóller Fm. is subdivided in three members. The lower one, Es Barraca Mb.. is composed of shallowing upward carbonate sequences with a micropaleontological assemblage of Sinemurían- Pliensbachian Age. Ihe middle one. Sa Molleta Mb., that appears only in some arcas.. consist of yellow marís with a characteristic fossil assemblage of Jamesoni and Ibex Zones of the Carixian.The upperone. Es Racó Mb.. is composed of siliciclastic sediments probably Late Cartxian in age.