A review of the European Neogene Mammal zones from integration of litho-, bio- and magnetostratigraphy in the Teruel Basin

The northern sector of the Teruel Basin (Spain) houses a dense and continuous record of late Neogene mammal fossil sites, as well as numerous biostratigraphic and magnetostratigraphic information making it a reference basin to define and refine the European mammal biostratigraphy from the Vallesian to the Villafranchian. The Neogene mammal chronology is in ongoing revision, and distinct correlations between basins and Europe provinces have been proposed based on their relative ages. New calibration methods based on numerical modelling have allowed the absolute ages of the paleontological sites to be refined. Nevertheless, some discrepancies arise, evidencing that ancho ring between absolute ages and mammal fossil record would benefit from a stronger stratigraphical framework. This work provides such a robust 3D stratigraphic framework of the whole basin that, together with magnetostratigraphy, allows establishing an accurate chronostratigraphic model and hence a precise chronology of sedimentary units and mammal sites. The absolute age of MN zones, or mammal stages, in the Teruel Basin has been revised on the basis of a detailed and confident stratigraphic correlation, and updated to the most recent Geomagnetic Polarity Time Scale. In particular, new accurate ages have been proposed for the boundaries MN 9/10 to MN 16/17 from data exclusively located in the Teruel Basin, with a precision generally of 0.1–0.2 Ma

Segmentation and increasing activity in the Neogene-Quaternary Teruel Basin rift (Spain) revealed by morphotectonic approach

The NNW-SSE trending Teruel Basin rift is the largest Late Miocene-Quaternary extensional intracontinental structure located within the central-eastern Iberian Chain (Spain). The structural and morphotectonic study carried out in the central-northern part of this half graben basin (north of Teruel city) has allowed us to analyse rift segmentation, deformation partitioning and rift evolution. Results are based on vertical displacement calculations (fault throw and bending) of the main border and intrabasin fault zones. We use two geomorfological-stratigraphical markers, the Intramiocene Erosion Surface (IES; 11.2 Ma) and the Fundamental Erosion Surface (FES; 3.5 Ma). While the first marker reveals rift initiation under an E-W extension, the late marker records vertical displacements associated to a second, Late Pliocene–Quaternary rifting stage characterized by a nearly multidirectional extension regime with prevailing ENE-WSW trending ó3. Despite the along-axis rift segmentation into three structural domains (northern, central and southern) and the distribution of deformation among border and intrabasin faults in the central and southern domains, a consistent average slip rate (post-IES) of 0.09 mm/a has been calculated on distinct transects across the basin, suggesting a homogeneous crustal-scale extension process in the region. The results also reveal that slip rates during the Late Pliocene-Quaternary (0.12–0.16 mm/a) are higher than the Late Miocene-Early Pliocene (0.05–0.07 mm/a). Slip rate increase is caused by (i) a westward propagation of deformation from the Valencia Through, and (ii) a change in the regional stress field, both enhanced by crustal doming affecting central-eastern Iberia, as well as progressive fault linkage. Throw vs. distance graphs suggest that the main faults are in a transient stage towards coalescence, less advanced within the southern domain. Regional Late Pliocene-Quaternary uplift, concomitant with increasing slip rates in the Teruel Basin rift, has caused the basin to rise, so that synrift sedimentation only took place in rapidly subsiding residual basins until the region became exorheic and the basin was incised by the present-day fluvial network

Alluvial sedimentation and tectono-stratigraphic evolution in a narrow extensional zigzag basin margin (northern Teruel Basin, Spain)

The northern part of the eastern margin of the extensional Neogene Teruel Basin (central-eastern Spain) consists of a non-linear, zigzag fault zone made of alternating ca. 2 km long, NNW-SSE trending segments and shorter NNE-SSW ones. Good outcrop conditions made possible a comprehensive integrated stratigraphic and structural study, especially focused on coarse clastic sediments deposited along the basin margin. Well-exposed stratal relationships with boundary faults, allowed the analysis of tectonic influence on sedimentation. Synsedimentary deformation includes growth faulting, rollover anticlines, and monoclines and associated onlap stratal terminations, angular unconformities, and other complex growth strata geometries. One of them is the onlap-over-rollover bed arrangement described here for the first time, which reveals the competition between tectonic subsidence and sedimentary supply. Both, the structural inheritance (dense Mesozoic fracture grid) and the dominant, nearly ‘multidirectional’ (s1 vertical, s2 ˜ s3), Pliocene extensional regime with s3 close to E-W, are considered to have controlled the margin structure and evolution. Tectono-stratigraphic evolution includes: (i) reactivation of inherited NNW-SSE faults and development of W-SW-directed small alluvial fans (SAF) while NNE-SSW segments acted as gentle relay ramp zones; (ii) progressive activation of NNE-SSW faults and development of NW-directed very small alluvial fans (VSAF); during stages i and ii sediments were trapped close to the margin, avoiding widespread progradation; (iii) linking of NNW-SSE and NNE-SSW structural segments, overall basin sinking and widespread alluvial progradation; (iv) fault activity attenuation and alluvial retrogradation. The particular structure and kinematic evolution of this margin controlled alluvial system patterns. Size of alluvial fans, directly set up at the border faults, was conditioned by the narrowness of the margin, small catchment areas, and proximity between faults, which prevented the development of large alluvial fans. The size of the relay zones, only a few hundred meters wide, acted in the same way, avoiding them to act as large sediment transfer areas and large alluvial fans to be established. These features make the Teruel Basin margin different to widely described extensional margins models

An approach to the seismic hazard at Teruel city associated to the Concud fault (NE Spain)

This paper presents the results ofa probabilistic seismic hazard analysis at Teruel city from seismological and geological information. The characteristic earthquake of the Concud fault (M ~ 6.8; recurrence period = 7.3 ±2.7 ka) has a probabilityof occurrence within a 500-yearperiod ranging from 2.3 to 26.1%. Its parameters fit precisely the magnitude-frequency pattern obtained from the historical seismicity of the Teruel and Jiloca grabens. This coherency supports an estimate of the maximum expectable seism within a 500-yearperiod: M = 5.4± 0.3. Empirical correlations indicate a potential intensity at Teruel overI= VII for this earthquake, and minimum peak ground acceleration ap = 0.105 g, higher than thatspecified by earthquake-resistant building regulationsSe presentan los resultados de un análisis probabilistico de peligrosidad sísmica en el entorno de Teruel a partir de la información geológica y sismológica. El terremoto característico de la falla de Concud (M ~ 6,8;periodo de retorno = 7,3 ±2,7 ka) tiene una probabilidad de ocurrencia en un plazo de 500 años de entre 2,3y26,1 %. Sus parámetros se ajustan bien a la extrapolación de la curva frecuencia-magnitud de la sismicidad histórica en el entorno de las fosas de Teruel yJiloca. En consecuencia, se hace una estimación de la magnitud del seísmo esperable en 500 años: M = 5,4± 0,3. Por correlación empírica se atribuye a éste una intensidad potencial en Teruel por encima de I = VII, y una aceleración de pico mínima ap = 0,105 g, superior a la especificada en la Norma Sismorresistent

Evaluating and comparing geochemical sampling protocols in dinosaur eggshells: refining Cretaceous ecosystem research

The geochemical signatures of dinosaur eggshells represent well-established proxies in paleoenvironmental and paleobiological research. The variable sampling procedures reported in the literature, however, deserve attention. In order to evaluate the impact of different sampling methodologies on carbon and oxygen isotope and elemental concentrations, grinding was contrasted with drilling to extract powder samples from eggshell fragments collected at several locations. Eggshell data were further contrasted with surface materials, encasing matrix and compared with independent proxies using petrographic and elemental techniques. Iron and manganese elemental concentrations revealed an enrichment sequence depending on the sampling strategy for the same eggshell fragment. This pattern can be mistaken for a variable state of preservation. In contrast, carbon and oxygen isotope values exhibited only subtle differences and lacked clear trends. This suggests that isotope data are less susceptible to different methodological approaches. It is shown that drilling offers a wider range of possibilities compared to grinding (e.g., faster and less destructive). Additionally, drilled powder samples can confidently be used for elemental and isotope analysis, excluding contamination, thus providing a more accurate set of proxy data from eggshell archives

refining Cretaceous ecosystem research

GeoBioTec Research Group (FCT – Fundação para a Ciência e Tecnologia, Portugal), by project PLEC2021-008203 project, funded by MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR” , by Gobierno de Aragón [Group E18: Aragosaurus: Recursos Geológicos y Paleoambientales]; and by project PID2021-122612OB-I00; Spanish Ministry of Science and Innovation MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR”,MCIN/AEI/10.13039/5011000110333. M. M-A is the recipient of a Ramon y Cajal contract RYC2021-034473-I. C. N.-L. is the recipient of a Juan de la Cierva-Formación contract FJC2020-044561-I, supported by the MCIN co-financed by the NextGenerationEU/PRTR. Sylvia Riechelmann is thanked for support during geochemical analysis and Cristina Sequeira for assisting SEM analysis. We thank Marcos Aurell (University of Zaragoza- Spain), for providing a vector file of the geological sketch in Fig. S1F . Constructive comments by two anonymous reviewers and editorial guidance provided by Eduardo Koutsoukos are also acknowledged. Publisher Copyright: © 2023 The Author(s)The geochemical signatures of dinosaur eggshells represent well-established proxies in paleoenvironmental and paleobiological research. The variable sampling procedures reported in the literature, however, deserve attention. In order to evaluate the impact of different sampling methodologies on carbon and oxygen isotope and elemental concentrations, grinding was contrasted with drilling to extract powder samples from eggshell fragments collected at several locations. Eggshell data were further contrasted with surface materials, encasing matrix and compared with independent proxies using petrographic and elemental techniques. Iron and manganese elemental concentrations revealed an enrichment sequence depending on the sampling strategy for the same eggshell fragment. This pattern can be mistaken for a variable state of preservation. In contrast, carbon and oxygen isotope values exhibited only subtle differences and lacked clear trends. This suggests that isotope data are less susceptible to different methodological approaches. It is shown that drilling offers a wider range of possibilities compared to grinding (e.g., faster and less destructive). Additionally, drilled powder samples can confidently be used for elemental and isotope analysis, excluding contamination, thus providing a more accurate set of proxy data from eggshell archives.publishersversionpublishe

Recent activity and paleoseismicity of an intraplate extensional fault: the Calamocha fault (Jiloca graben, central Iberian Chain)

The Calamocha fault is an 18-km-long, NNW–SSE striking pure normal fault that moves down the northern sector of the Jiloca graben with respect to the Neogene infill of the Calatayud basin (central Iberian Chain). Its structure and kinematics are characterized by means of detailed geological mapping, morphotectonic analysis and data recording at the outcrop scale. The Calamocha fault represents the inversion of a previous contractional fault zone under the recent tensional stress field (WSW–ENE trending σ3 trajectories). The extensional activity started during the Late Pliocene (ca. 3.8 Ma), accumulating a maximum net slip of 190–230 m (long-term slip rate of 0.05–0.06 mm/a). The palaeoseismological study of three artificial exposures near Calamocha town evidenced recurrent slip during the Late Pleistocene, which proves its active character. Analysis of faulted clastic alluvial units, dated by means of optically stimulated luminescence (OSL), reveals at least eight slip events since 145.9 ± 9.1 ka, the last one being younger than 13.8 ± 0.9 ka. Only a few events represent visible accumulated displacement on the main synthetic rupture surfaces; this allows a rough estimate of the short-term slip rate (during the Late Pleistocene) of about 0.1 mm/a, faster than the long-term rate. The Calamocha fault could potentially produce a characteristic earthquake (in the sense of Schwartz and Coppersmith, J Geophys Res 89:5681–5698, 1984) with moment magnitude Mw ≈ 6.7 ± 0.3 (Mw ≈ 6.9 ± 0.3 in a scenario of activation of the whole Calamocha–Daroca fault zone), average coseismic displacement of 0.5–1.3 m and average recurrence period under 15 ka

Mapa de asociaciones de facies Neógenas del sector norte de la Cuenca de Teruel

El relleno sedimentario mioceno superior-cuaternario del sector norte de la Cuenca de Teruel se caracteriza por asociaciones de facies referibles a abanicos aluviales, medios lacustres, palustres y, menos frecuentes, eólicos y deltaicos. La cartografía de dichas asociaciones de facies y de las estructuras tectónicas muestra una configuración propia de cuencas extensionales asimétricas. Los abanicos aluviales, principalmente procedentes de los márgenes oriental y occidental de la cuenca, presentaban diferentes dimensiones, siendo de mayor extensión los del margen occidental, tectónicamente inactivo durante el depósito de la serie estudiada. Los abanicos aluviales conectaban con lagos poco profundos situados en áreas centrales pero más próximas al margen activo. El espacio de acomodación generado por fallas sinsedimentarias intracuencales favoreció la preservación de asociaciones de facies eólicas y deltaicas, poco frecuentes en este tipo de cuencas continentales. The Upper Miocene-Quaternary sedimentary fill of the northern sector of the Teruel Basin is characterized by facies associations corresponding to alluvial fans, lakes and palustrine areas, as well as less common aeolian and deltaic environments. The map of facies associations corresponding to different sedimentary environments, and tectonic structures, reveals asymmetrical fill architecture. Alluvial fans were mainly sourced from the eastern (tectonically active) and western (passive) basin margins, connected downstream with shallow carbonate or evaporite lakes located in central basinal areas but closer to the active margin. The accommodation space created by synsedimentary intrabasinal faults enabled preservation of aeolian and deltaic associations, not very common in this type of basins

Aproximación a la peligrosidad sísmica en la ciudad de Teruel asociada a la falla de Concud (NE España)

Se presentan los resultados de un analisis probabilistico de peligrosidad sismica en el entorno de Teruel a partir de la informacion geologica y sismologica. El terremoto caracteristico de la falla de Concud (M . 6,8; periodo de retorno = 7,3} 2,7 ka) tiene una probabilidad de ocurrencia en un plazo de 500 anos de entre 2,3 y 26,1 %. Sus parametros se ajustan bien a la extrapolacion de la curva frecuencia-magnitud de la sismicidad historica en el entorno de las fosas de Teruel y Jiloca. En consecuencia, se hace una estimacion de la magnitud del seismo esperable en 500 anos: M = 5,4} 0,3. Por correlacion empirica se atribuye a este una intensidad potencial en Teruel por encima de I = VII, y una aceleracion de pico minima ap = 0,105 g, superior a la especificada en la Norma Sismorresistente. This paper presents the results of a probabilistic seismic hazard analysis at Teruel city from seismological and geological information. The characteristic earthquake of the Concud fault (M ˜6.8; recurrence period = 7.3 ± 2.7 ka) has a probability of occurrence within a 500-year period ranging from 2.3 to 26.1%. Its parameters fit precisely the magnitude-frequency pattern obtained from the historical seismicity of the Teruel and Jiloca grabens. This coherency supports an estimate of the maximum expectable seism within a 500-year period: M = 5.4 ± 0.3. Empirical correlations indicate a potential intensity at Teruel over I = VII for this earthquake, and minimum peak ground acceleration ap = 0.105 g, higher than that specified by earthquake-resistant building regulations

Iberfault 2022. IV Reunión Ibérica sobre Fallas Activas y Paleosismología. Volumen de resúmenes, Teruel, 7 al 10 de septiembre de 2022

SESIÓN 1: Tectónica activa y paleosismología de las Cordilleras Béticas (I) SESIÓN 2: Tectónica activa y paleosismología del resto de la Península Ibérica SESIÓN 3: Sismología y sismicidad inducida SESIÓN 4: Arqueosismología SESIÓN 5: Tectónica activa y paleosismología de las Cordilleras Béticas (II) SESIÓN 6: Tectónica activa en el medio marino SESIÓN 7: Geodesia aplicada a tectónica activa SESIÓN 8: Modelización sismotectónic