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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.

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.