Primer registro de reptiles marinos triásicos (notosaurios, sauropterigios) del Complejo Alpujárride (Zonas Internas de la Cordillera Bética, España)

This work reports the first record in the Internal Zones of the Betic Cordillera of a vertebrate fossil remain, more exactly a rib, corresponding to a marine reptile (Sauropterygia). The development of epicontinental platforms restricted to the Tethys Ocean during the fragmentation of Pangea since the late Lower Triassic favoured the radiation of Sauropterygia, diapsid marine reptiles including Placodontiformes, Pachypleurosauria, Nothosauroidea, and Pistosauroidea. The Triassic of the Alpujarride Complex, in the Internal Zones of the Betic Cordillera, SE Spain, comprises the carbonate deposits of these epicontinental platforms developed during the Middle-Late Triassic in the northern margin of the Mesomediterranean Massif. The studied stratigraphic interval is located at Sierra de Lújar (Granada Province) and consists of 17.5-m thick succession of alternating fossiliferous marls and limestones with local intense bioturbation and abundance of macroinvertebrates. The studied interval represents shallow facies of the inter- to subtidal environment as deduced by the record of Lofer cycles and the record of carbonated breccia at the top of the sequence likely related to storm events. Lofer cycles display lamination at their bases and intense bioturbation and abundant bivalves towards the top. A 15-cm long dorsal rib of a sauropterygian, likely a nothosaur, was recorded in this succession. It is well preserved, without evidence of original fragmentation, borings, or encrustations. This study shows for the first time fossil bones of marine reptiles in the Alpujarride Complex, which inhabited the shallow-water environments during the Triassic, equivalent to the marine reptiles recorded in other areas such as the Iberian Palaeomargin and other central Europe basins.Este trabajo documenta el primer registro de vertebrados fósiles, concretamente de un reptil marino (sauropterygia), en las Zonas Internas de la Cordillera Bética. El desarrollo de plataformas epicontinentales en el Tetis durante la fragmentación de Pangea a partir del Triásico Inferior tardío favoreció la radiación de los sauropterigios, grupo de reptiles diápsidos marinos que incluye a los clados Placodontiformes, Pachypleurosauria, Nothosauroidea y Pistosauroidea. Los materiales triásicos del Complejo Alpujárride de las Zonas Internas de la Cordillera Bética, SE de España, incluyen los depósitos carbonatados correspondientes a las plataformas epicontinentales desarrolladas durante el Triásico medio-superior en el margen norte del Macizo Messomediterraneo. El intervalo estratigráfico seleccionado se encuentra en la Sierra de Lújar (Granada) y es una sucesión de 17,5 m de potencia con una alternancia de margas y calizas fosilíferas con abundante bioturbación y restos de macroinvertebrados. Se han identificado ciclos loferíticos con laminación a la base que cambia a un sedimento intensamente bioturbado con abundantes bivalvos hacia el techo del ciclo. El intervalo de estudio representa facies someras en un ambiente inter- o submareal como indican los ciclos loferíticos y la presencia de brechas carbonatadas en el techo de la secuencia, presumiblemente relacionadas con tormentas. Una costilla dorsal de 15 cm de longitud de un sauropterigio, probablemente un notosaurio, ha sido descubierta en esta serie en buen estado de conservación y sin evidencias de fragmentación, perforaciones o encostrantes. Este estudio muestra por primera vez la presencia de restos fósiles de reptiles marinos en el Complejo Alpujárride, reptiles que vivieron en aguas someras durante el Triásico al igual que se ha documentado en el Paleomargen Ibérico y en algunas cuencas triásicas de Europa central.Juan de la Cierva Program Ministerio de Ciencia, Innovación y Universidade

Foraminiferal morphogroups in dysoxic shelf deposits from the Jurassic of Spitsbergen

Analysis of benthic foraminiferal assemblages was performed in Bathonian to Kimmeridgian deposits through a section covering the lower half of the Agardhfjellet Formation in central Spitsbergen. The section consists mainly of organic-rich shales, which contain low-diversity agglutinated assemblages. In this foraminiferal succession five morphogroups were differentiated according to shell architecture (general shape, mode of coiling and number of chambers), integrated with the supposed microhabitat (epifaunal, shallow infaunal and deep infaunal) and feeding strategy (suspension-feeder, herbivore, bacterivore, etc.). The environmental evolution of the analysed section is interpreted by using the stratigraphic distribution of morphogroups, combined with species diversities and sedimentary data, in a sequence stratigraphic framework. The section comprises two depositional sequences, which demonstrate that species diversity and relative frequency of morphogroups are correlative with transgressive–regressive trends controlling depth and oxygenation of the water column. In both sequences, the maximum flooding interval is characterized by increased organic carbon content, dominance of the epifaunal morphogroups and reduced species diversity: features reflecting the increased degree of stagnation separating the transgressive phase from the regressive phase.The participation of J. Nagy in this research has been supported by the Statoil/Hydro VISTA programme. The contribution of M. Reolid and F.J. Rodríguez-Tovar has been supported by the projects CGL2005-06636-C0201 and CGL2005-0316/BTE, the EMMI group (RNM-178, Junta de Andalucía) and the Acción Integrada 30.AI.PO.1300 (University of Granada–University of Oslo). A grant of the Universidad de Jaén financed M. Reolid’s short stay at the University of Oslo

Lower/Middle Ordovician (Arenigian) shallow-marine trace fossils of the Pochico Formation, southern Spain: palaeoenvironmental and palaeogeographic implications at the Gondwanan and peri-Gondwanan realm

Nineteen ichnospecies belonging to thirteen ichnogenera (Archaeonassa, Catenichnus, Cochlichnus, Cruziana, Didymaulichnus, ?Diplichnites, Gordia, Lingulichnus, Lockeia, cf. Monocraterion, Planolites, Ptychoplasma, and Rusophycus) occur in the Pochico Formation (Arenigian) in the Aldeaquemada section, Sierra Morena, southern Spain, just above the Armorican Quartzite. They belong to the archetypal Cruziana ichnofacies, indicating a lower shoreface-upper offshore zone. The low degree of sediment reworking may be due to a high rate of sedimentation. The trace fossil assemblage, rich in large Cruziana, is typical of the Armorican Quartzite that developed on the margins of Gondwana and peri-Gondwanan microcontinents. The distribution of ichnofauna during the Early Ordovician was partly palaeogeographically controlled, although ichnological data from the literature point to paths of migration between Gondwana, Baltica and Laurentia. Differences between the ichnofauna of Gondwana and Baltica could be conditioned by facies (clastics in Gondwana and carbonates in Baltica) causing a taphonomic filter, because Cruziana requires diversified clastic deposits for preservation. The ichnofauna would also be influenced by trophic group amensalism between filter feeding and deposit feeding fauna, the former prevailing in Baltica and the latter in Gondwana.Se presenta el análisis sedimentológico/icnológico de los materiales de la Formación Pochico (Arenigian) de la sección de Aldeaquemada, Sierra Morena, Sur de España, provincia de Jaén, justo por encima la Cuarcita Armoricana. Se han reconocido diecinueve icnoespecies pertenecientes a trece icnogéneros (Archaeonassa, Catenichnus, Cochlichnus, Cruziana, Didymaulichnus, ?Diplichnites, Gordia, Lingulichnus, Lockeia, cf. Monocraterion, Planolites, Ptychoplasma, y Rusophycus). Las características icnológicas junto con los rasgos sedimentológicos permiten asignarlas a las icnofacies arquetípicas de Cruziana, comunes de las zonas de shoreface inferior a offshore superior. El grado de bioturbación relativamente bajo puede estar relacionado con una alta tasa de depósito. La asociación registrada, dominada por grandes Cruziana, es típica de la Cuarcita Armoricana desarrollada en los márgenes de Gondwana y peri-Gondwana. La distribucción de icnofósiles del Ordovícico temprano posee, en gran medida, un control paleogeográfico, aunque datos icnológicos procedentes de la literatura indican la existencia de migraciones entre Gondwana, Baltica y Laurentia. Las diferencias entre las asociaciones de Gondwana y Báltica pueden estar asociadas a las diferentes facies, con el dominio de materiales clásticos en Gondwana y de carbonatados en Báltica, causando un filtro tafonómico ya que el potencial de conservación de Cruziana es mucho mayor en las facies clásticas heterolíticas. A estos factores habría que añadir las estrategias de alimentación asociadas, diferenciando entre filtradores y aquellos que se alimentan de las partículas existentes en el sedimento, los primeros podrían verse favorecidos en Báltica y los segundos en Gondwana.Research by R.-T. was supported by Projects CGL2008-03007, and CGL2012-33281 (Secretaría de Estado de I+D+I, Spain), Project RNM-3715 and Research Group RNM-178 (Junta de Andalucía)

Evidence of phyllosilicate alteration processes and clay mineral neoformation promoted by hydrothermal fluids in the Padul Fault area (Betic Cordillera, SE Spain)

Acknowledgements We acknowledge the technical and human support provided by CICT of Universidad de Ja´en (UJA, MINECO, Junta de Andalucía, FEDER). Cecilia de la Prada is especially recognized for helping with the HRTEM work. The access to the HAADF Thermo Fisher Scientific TALOS F200X microscope was facilitated by the Centro de Instrumentaci´on Científica of the Universidad de Granada. The authors are indebted to responsible of the JUMA Quarry and El Mill´on Quarry. Thanks are extended to B. Dubacq and an anonymous reviewer for their critical reviews and helpful comments and suggestions.Supplementary data to this article can be found online at https://doi. org/10.1016/j.clay.2022.106669.Funding This research was supported by the project PGC2018-094573-B-I00 from the MCIU-AEIFEDER and the research groups RNM-325, RNM-200 and RNM-179 of the Junta de Andalucía.Geochemical changes and authigenic clays were detected in the fault rocks of the Padul Fault. An enrichment from the protolith to the ultracataclasites in Si, Al, Fe, Ca, Ti and also Zn but an impoverishment in Mg was detected. Although the protolith (dolostones) and fault rocks are mostly composed of carbonates, the fault rocks are also characterized by the presence of fine-grained clays in the matrix (mainly chlorite and Mg-rich biotite, but also smectite and punctually talc). Neither chlorite nor talc were detected in the protolith. The application of chlorite thermometry gives temperatures around 140–220 °C for chlorites lamellae located on the fault plane. These chlorites are compositionally homogeneous, whereas the chlorites detected in the cataclasites are more variable, although both of them are Mg-rich and have almost no Fe. As well, chlorites from the cataclasites usually include Zn in their composition and, as observed at nanoscale, they are genetically related to biotites, which come from the protolith. Talc grains (< 1 μm) are always found between dolomite and calcite. These observations point to clay mineral reactions in the fault rocks as the chlorite and talc precipitation promoted by circulation of fault-controlled hydrothermal fluids close to 200 °C. Other clays such as smectite are the result of the final step of the hydrothermal activity in the fault. The identification of authigenic clay minerals, which cause weakening mechanisms, is consistent with the geodetic characterization of the Padul Fault, which plays an important role in aseismic deformation.Project PGC2018-094573-B-I00 from the MCIU-AEIFEDERResearch groups RNM-325, RNM-200 and RNM-179 of the Junta de Andalucí

Dinamica eco-sedimentaria durante el oxfordiense medio-kimmeridgiense temprano en la zona prebética : interpretación ecoestratigráfica y secuencial

Esta investigación profundiza en el conocimiento de la plataforma epicontinental desarrollada en el Margen Sudibérico durante el intervalo Oxfordiense medio-Kimmeridgiense temprano (Jurásico superior), a partir del estudio de los materiales registrados en la Zona Prebética (Cordillera Bética). El resultado final se fundamenta en la consecucción de unos objetivos parciales cuyos resultados han sido los siguientes: 1,- El análisis de las microfacies y del estudio macroscópico de los materiales, ha permitido la caracterización de cinco grupos de liltofacies: litofacies grumosas, litofacies espongiolíticas, litofacies de ritmita margoso-calcárea, litofacies de mangas y litofacies de caliza con oolitos ferruginosos. 2,- El estudio detallado de los carbonatos de origen microbiano ha permtidio clasificar las microbialitas tanto desde el punto de vista microscópico como microscópico. La microbialita tiene un papel fundamental en la formación de las bioconstrucciones. Se han reconocido bioconstrucciones simples y complejas, constituidas por una fase de biohermo de esponjas y una fase de litohermo microbiano. 3,- El análisis de las asociaciones de foraminíferos, su distribución y relación con las litofacies ha permitido diferenciar una asociación relativamente proximal (Prebético Externo) de otra más distal (Prebético Interno). 4,- La bioestratigrafia a nivel de zona se ha basado en el análisis de los ammonoideos, reconociendo desde la Zona Transversarium (Oxfordiense medio) a la Zona Platynota (Kimmeridgiense inferior). 5,- Se ha realizado un estudio tafonómico de los macroinvertebrados fósiles registrados, centrado en: modalidad de conservación, tamaño de los ejemplares, posición en el estrato, "corrasion", fragmentación, epibiontes y encostramientos, desarticulación, desacoplamiento, facetado y deformación. Se han diferenciado cuatro tafofacies, I, II, III y IV. 6,- El análisis de la composición de las asociaciones de macroinvertebrados y de su diversidad permite reconocer las tendencias existentes de acuerdo con el gradiente proximal-distal de la plataforma y la diferenciación de asociaciones tipo para los macroinvertebrados bentónicos fósiles, así como su relación con las litofacies. 7,- La evolución ecoestratigráfica de las asociaciones en su contexto estratigráfico pone de manifiesto fenómenos de reducción y expansión del ecoespacio en respuesta a cambios del nivel relativo del mar. 8,- Finalmente se lleva a cabo un análisis integrado en el marco de la estratigrafia secuencial, con la interpretación de variaciones en el grado de proximalidad-distalidad relativa de los depocentros y del ecoespacio, en relación con fluctuaciones relativas del nivel del marUniversidad Granada, Departamento de Estratigrafía y Paleografía. Leída el 08-05-200

Textural and genetic relationships between glauconite and celadonite at the nanoscale: two different structural-compositional fields

We acknowledge the use of the LMA-INA (Universidad de Zaragoza) for access to dual beam equipment and expertise, the technical and human support provided by CICT of Universidad de Jaén (UJA, MINECO, Junta de Andalucía, FEDER), and the use of the PANalytical X'Pert Pro diffractometer of the Departamento de Mineralogía y Petrología, Universidad de Granada, Spain. María del Mar Abad is especially recognized for helping with the HRTEM work. The access to the HAADF FEI TITAN G2 microscope and the Philips CM20 (STEM) microscope was facilitated by the Centro de Instrumentación Científica of the Universidad de Granada. Thanks are extended to Javier Cuadros and an anonymous reviewer for their critical reviews and very helpful comments and suggestions.Glauconite and celadonite coexist at the nanometre scale in Early Jurassic submarine volcanic rocks of the Betic Cordillera (southern Spain) as a result of microbial activity. Samples from the limit between the two micas, recognizable in scanning electron microscopy, have been extracted using the focussed ion beam technique and studied by high-resolution analytical electron microscopy. Both micas are present as randomly oriented differentiated small crystals in the boundary area. They define clearly distinct compositional fields with gaps affecting to Fe, Mg and K. At the lattice scale, celadonite shows a high degree of order, with homogeneous orientation of the visible lattice parameters being a difference from glauconite, formed by packets no more than 10-layers thick. Smectite layers were also detected alongside glauconite packets, in accordance with X-ray diffractograms which indicate that glauconite is a mica-smectite interstratification being more than 90 % mica layers. The compositional gap indicates that celadonite is not the endmember of the glauconitic series and the two micas represent two different structural tendencies of mica, with glauconite having more distorted octahedral sheets, indicated by systematically higher b parameters than celadonite.MCIU-AEIFEDER PGC2018-094573-B-I00 ,PID2019-104624RB-I00 and RTI2018-093419-B-I00Junta de Andalucia RNM-325, RNM-200 and RNM-179Gobierno de Aragon E18_17REuropean Fun