Browsing by Author "Coronado Vila, Ismael"
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Publication A new early Visean coral assemblage from Azrou-Khenifra Basin, central Morocco and palaeobiogeographic implications(Springer, 2020) Rodríguez, Sergio; Somerville, Ian D.; Cózar Maldonado, Pedro; Sanz-López, Javier; Coronado Vila, Ismael; González, Felipe; Said, Ismail; El Houicha, MohamedA new early Visean coral assemblage has been recorded from turbidite facies in the southern part of the Azrou-Khenifra Basin, northwest of Khenifra, central Morocco. The newly discovered Ba Moussa West (BMW) coral fauna includes Siphonophyllia khenifrense sp. nov., Sychnoelasma urbanowitschi, Cravenia lamellata, Cravenia tela, Cravenia rhytoides, Turnacipora megastoma and Pleurosiphonella crustosa. The early Visean age of the coral assemblage is supported by foraminiferal and conodont data, with the recognition of the basal Visean MFZ9 Zone. This confirms that the first transgression in the Azrou-Khenifra Basin was during the earliest Visean. The allochthonous coral assemblage was recovered from coarse-grained proximal limestone debris flow and turbidite beds within a fault-bounded unit, lying to the west of a thrust syncline containing upper Visean limestones. No evidence exists of the former early Visean shallow-water platform from which the corals were derived. All other in situ platform carbonate rocks around the southern margin of the Azrou-Khenifra Basin are probably of late Visean (Asbian–Brigantian) age. The early Visean Ba Moussa West coral fauna can be compared with that at Tafilalt in eastern Morocco, as well as in other Saharian basins of Algeria. Many of the genera and species in the Ba Moussa West assemblage are identical to those in NW Europe, with which it must have had marine connections. The new rugose species described, Siphonophyllia khenifrense, is probably endemic to North Africa. Its ecological niche in NW Europe was occupied by S. cylindrica or S. aff. garwoodi.Publication Algal diversity during the onset of the Late Paleozoic Ice Age in low-latitude basins of the Western Palaeotethys(Elsevier, 2023-11) Cózar Maldonado, Pedro; Somerville, Ian D.; Hounslow, Mark W.; Mateos Carralafuente, José Ricardo; Coronado Vila, IsmaelA study of calcareous algae from the late Viséan to Serpukhovian interval in basins from the western margin of Palaeotethys (basins located currently in Western Europe and Northern Africa) shows varied responses in terms of palaeoecological diversity, specimen abundance, genus richness and taxonomic distinctness for the low-latitude basins. Algal associations are more similar in cratonic areas, although many local diversity peaks correspond to ecological/environmental factors. Terranes with Laurussian affinities contain the most unusual abundances and seem to be the most affected by palaeogeographic reorganization and local tectonics. Algae from the palaeo-equatorial zone show more dramatic changes than those in the southerly tropics. The varied results suggest that it is not suitable to extrapolate a particular diversity result from a single region to global conditions, since many factors have influenced the regional assemblages. The main taxonomic turnover of most fossil groups occurred from the uppermost Serpukhovian, linked to a severe cooling phase inferred by δ18O data from brachiopods. It coincides with the post-glacial phase C1 defined in eastern Australian basins. Most ecological changes occurred from the early Serpukhovian, predating the glacial phase C1 and coinciding with the Main Eustatic Signal. Far-field proxies used to define the onset of icehouse intervals in the LPIA are inconsistent and are located several million years before the main biota changes. This questions the definition of the onset of sustained icehouse glaciation at different levels of the low palaeolatitude Viséan, without the resulting modifications in the warm-water biota.Publication Alternating microbial mounds and ooidal shoals as a response to tectonic, eustatic and ecological conditions (late Viséan, Morocco)(Elsevier, 2022-04-01) Cózar Maldonado, Pedro; Coronado Vila, Ismael; García Frank, Alejandra; Izart, Alain; Somerville, Ian D.; Vachard, DanielThe succession in the Tizra Formation shows an excellent exposure of a small open marine platform where alternating microbial boundstones (buildups) and oolitic/bioclastic grainstone (shoals) and packstone facies tempestites occur repetitively for a sort interval only 0.55 Myr, an scenario unknown in the geological record. The relatively small extent of the platform allows a detailed study of facies and ecological variations, to determine the controlling factors for the growth and evolution of the platform (tectonics, glacioeustatism, terrigenous input), as well as the particular environmental/ecological conditions for the formation of microbial buildups and oolitic shoals (turbidity, energy, nutrients, chemical variations). Although microbial mounds are well-known during the Palaeozoic, the close relationship with ooids, as observed in the studied succession, is unusual, particularly for the frequent ooids embedded in the microbial facies, an ecological parameter used by previous authors to identified shallower stages in the microbial growths. Petrographic analysis of the ooids, as well as their ecological conditioning, suggest that less than 40% of samples yield ooids generated in situ, whereas there is a predominance of transported ooids. Ooids formed in situ, which include large irregular and elongated ooids, were generated in calmer water than the typical rounded and egg-shaped ooids. The occurrence of the predominant types of ooids in shallower-water grainstones with in situ generation, and in the deepest-water microbial facies, suggest their ease of transport. The higher production of ooids occurs during the shallowing phases of the cycles, whereas they were more easily transported during the deepening phases, whereas in the microbial buildups, no features of in situ ooid generation are found.Publication Análisis de microfacies de los montículos de la Formación Cosgaya. Sección de Las Ilces, Pensilvánico, Cantabria(Universidad Complutense de Madrid, Servicio de Publicaciones, 2009) Coronado Vila, Ismael; Rodríguez, SergioEl Grupo Potes (Pensilvánico, Valle de Liébana, Cantabria) está formado por una sucesión rítmica de pizarras y areniscas entre las que se intercala la Fm Cosgaya, constituida fundamentalmente por calizas. Estas calizas presentan un abundante contenido de algas y corales que en algunos puntos forman bioconstrucciones. Estas bioconstrucciones son especialmente notables en la sección de Las Ilces, donde se han identificado siete microfacies diferentes: MF-1, Wackestone bioclástico con pequeñas masas de Donezella estabilizantes; MF-2, Boundstone de organismos estabilizadores y soportantes; MF-3, Boundstone/Packstone de intraclastos y peloides; MF-4, Wackestone/Packstone bioclástico; MF-5, Boundstone/Packstone de Donezella, MF-6, Packstone peloidal bioclástico; MF-7, Mudstone/wackestone de calcisferas y ostrácodos. Estas microfacies corresponden a las distintas zonas de montículos formados por comunidades microbianas, algas y corales y a las áreas próximas a los mismos. [ABSTRACT] The Potes Group (Pennsylvanian, Liébana Valley, Cantabria N Spain) is composed of a rhythmic succession of shales and sandstones and contain the Cosgaya Formation. The Cosgaya Formation is composed of organic limestones that show abundant algae and corals and locally form mounds. Those mounds are conspicuous at Las Ilces Section where seven microfacies have been identified: MF-1, Bioclastic wackestone with Donezella stabilizing patches; MF-2, Boundstone of stabilizing and supporting organisms; MF-3, Boundstone/Packstone of intraclasts and peloids; MF-4, Bioclastic Wackestone/Packstone; MF-5, Donezella Boundstone/Packstone; MF-6, Bioclastic and peloidal Packstone; MF-7, Mudstone/wackestone with calcisferas and ostracods. These microfacies correspond to diferent parts (or zones) of mounds formed by microbial communities, algae and corals and the close areas of themPublication Bioacumulación de Filosilicatos en las Paredes de un Micro-Burrow de Gusano del Carbonífero.(Sociedad Española de Mineralogía, 2010-09) Coronado Vila, Ismael; Rodríguez, SergioPublication Biomineralización de los corales aulopóridos del carbonífero(Universidad Complutense de Madrid, 2015-07-03) Coronado Vila, Ismael; Rodríguez García, SergioEsta tesis se centra en la caracterización a escala biomineral de los esqueletos de los corales aulopóridos del Carbonífero, con la propuesta de establecer un modelo de biocristalización general y su implicación en la biomineralización de los corales paleozoicos. La mayor parte del material proviene de afloramientos carboníferos de la península ibérica, aunque también se ha contado con material Devónico y Carbonífero proveniente del Muséum National d¿Histoire Naturelle (MNHN) de París (Francia), así como material de corales actuales del mar de Alborán (Granada, España) a modo de comparación. La tesis está confeccionada por artículos publicados e inéditos. Primeramente se ha caracterizado la diversidad, paleoecología y bioestratigrafía de los aulopóridos de la península ibérica, que corresponde con la mayor parte del material de estudio. Posteriormente se ha realizado la caracterización biomineral a partir del estudio de las propiedades cristaloquímicas preservadas en los esqueletos fósiles. Para ello se ha empleado la microscopía petrográfica, microscopía electrónica de barrido (SEM), microscopía de fuerza atómica (AFM), difracción de electrones retrodispersados (EBSD), análisis de microsonda de electrones (EMPA), microscopía de polarización integrada por ordenador (CIP), microscopía de epifluorescencia (EFM), microscopía de barrido laser confocal (CLSM), espectroscopía de infrarrojo por transformada de Fourier (FTIR), electroforesis SDS-PAGE y análisis de aminoácidos. Se ha estudiado de manera multidisciplinar el estado de preservación de los corales fósiles con el fin de establecer los criterios para reconocer estructuras esqueléticas biogénicas y secundarias (derivadas de la alteración diagenética). Se han desarrollado y aplicado nuevas metodologías que ayudan en la identificación de estructuras secundarias producidas por alteración diagenética. Se han analizado las propiedades cristaloquímicas de los biominerales y se han vislumbrado los procesos de crecimiento, organización interna, ensamblaje y el rol de las matrices orgánicas en los esqueletos de los corales paleozoicos. Se ha extraído y caracterizado por primera vez las matrices orgánicas que conforman los esqueletos de corales paleozoicos y se ha comparado con las matrices de los escleractinios. La combinación de datos bioquímicos, estructurales y cristalográficos ha permitido confirmar un modelo de biocristalización similar al modo de crecimiento coordinado por pasos. Este modelo defiende la hipótesis de que un hidrogel orgánico controla la cristalización a nano- y microescala. Esta capa de hidrogel sería secretada por las células epiteliales y controlaría el crecimiento de los elementos estructurales y esqueléticos. Por otra parte los datos a nanoescala confirman que el crecimiento esquelético es producido por un mecanismo similar a puentes minerales en una distribución dendrítica por parches interdigitados durante el crecimiento. El crecimiento de los elementos estructurales microcristalinos se formaría a partir de un crecimiento competitivo entre ellos, como ocurre con otros grupos de organismos que generan sus esqueletos con CaCO3. Por último se ha enfatizado el empleo de los estudios de biomineralización en la resolución de problemas paleontológicos.Publication Caracterización de minerales de uranio con espectroscopía de reflectancia de laboratorio: estudio del yacimiento de fósiles de Córcoles, Guadalajara(Sociedad Geológica de España) Cruz, Juncal A.; Coronado Vila, Ismael; Ferrer Juliá, Montserrat; Fernández Díaz, Lurdes; García Meléndez, Eduardo; Colmenero Hidalgo, Elena; Fernández Martínez, EsperanzaEn la naturaleza, el ion uranilo se asocia comúnmente a arseniatos, fosfatos y vanadatos; uno de los orígenes secundarios más frecuentes del uranio está asociado a fosfatos cálcicos biogénicos. En este estudio se han caracterizado minerales de uranio con espectroscopia de reflectancia VNIR-SWIR de laboratorio (400-2500 nm). Entre las muestras estudiadas se han incluido los minerales secundarios de uranio: metatorbernita, metautunita y metauranocircita, así como fosfatos cálcicos (biogénicos e inorgánicos) y fósiles coexistentes con mineralizaciones de metatyuyamunita encontrados en el yacimiento de vertebrados del Mioceno inferior de Córcoles (Cuenca del Tajo, Guadalajara, España). Este yacimiento representa un ejemplo de la formación de minerales secundarios de uranio de tipo fosfatos. Su origen es el resultado de la interacción de los fósiles con aguas subterráneas u otros fluidos mineralizadores portadores de uranilo (UO2 2+) durante la diagénesis. Los minerales con uranilo muestran rasgos de absorción a 1100, 1330 y 1672 nm atribuidos a los aniones uranilo. Dada la escasa información preexistente, la caracterización de los minerales que contienen uranio aporta valiosa información con gran potencial para ser aplicada en teledetección. Los datos obtenidos pueden ser de utilidad en la exploración, caracterización y/o protección de los yacimientos de uranio.Publication Carboniferous auloporids from the Iberian Peninsula: palaeocology, diversity, and spatio-temporal distribution(Universidad Complutense de Madrid ; Consejo Superior de Investigaciones Científicas, 2014) Coronado Vila, Ismael; Rodríguez, SergioAuloporid corals are common in the Palaeozoic and very frequent in the Carboniferous buildups of the Iberian Peninsula. The aim of this study is to analyze the diversity of these corals through a taxonomical recognition of the species and morphotypes that occur in the Iberian Peninsula. Eighteen sections have been sampled between the Ossa-Morena (Mississippian) and Cantabrian (Pennsylvanian) zones dated as upper Viséan to early Kasimovian. In addition, other localities where auloporids occur and are cited in the literature have been also used for this study. The taxonomical identification has been carried out using the criteria proposed by Tchudinova (1980) with little modifications. Thus, eighteen morphotypes and two species belonging to nine nominal genera have been identified (Multithecopora sp.A-H, Syringopora sp. A-B, Aulopora sp. A-B, Cladochonus sp. A-B, Syringoalcyon sp., Roemeripora sp., Sinopora sp., Mastopora? sp., Multithecopora hontoriense and Neomultithecopora cantabrica). Through a classical microfacies study, the environments where the auloporids lived have been identified, as well as the growth patterns and the features of sedimentation. Finally, a preliminary biostratigraphic range chart for the Carboniferous auloporoids from the Iberian Peninsula has been achieved.Publication Computer-integrated polarisation (CIP) in the analysis of fossils: a case of study in a Palaeozoic coral (Sinopora, Syringoporicae, Carboniferous)(Taylor and Francis, 2015-07) Coronado Vila, Ismael; Pérez Huerta, Alberto; Rodríguez, SergioComputer-integrated polarisation (CIP) method has been applied satisfactorily in the study of fossils skeletons of Sinopora (tabulate coral, Auloporida and Carboniferous). A previous characterisation of sample by scanning electron microscopy, atomic force microscopy and cathodoluminescence (CL) with the purpose of distinguishing the diagenetical alteration was done. Subsequently, a crystallographic comparison between CIP and electron-backscattering diffraction has been made getting a very good correlation between both methods. The CIP method allows obtaining c-axis orientation images, pole figures, and measure and mapping the misorientation of uniaxial biominerals in recent and fossil skeletons. This technique can only be used in uniaxial biominerals (calcite, quartz and hydroxylapatite), limiting its use for biaxial or bimineralic and polimineralic biominerals. CIP method has good spatial resolution (limited by camera); in our example 90 nm. The main advantage of this technique, versus other with similar properties, is the fast acquisition of data in low and high magnifications. This method does not require special treatment of samples and can be very useful for the analysis of microstructures in thin and ultra-thin sections. CIP method detects diagenetic alterations in fossil skeletons by modifications in the inner arrangement of biominerals, which combined with CL offers valuable geochemical and crystallographic information.Publication Contrasting reef patterns during the evolution of the carboniferous azrou-khenifra basin (Moroccan Meseta)(Springer Nature, 2022-11-12) Cózar Maldonado, Pedro; Somerville, Ian D.; Rodríguez García, Sergio; El Houicha, Mohamed; Vachard, Daniel; García Frank, Alejandra; Coronado Vila, Ismael; Izart, AlainFive types of reefs are described from the northern and southern parts of the Azrou-Khenifra Basin generated by the interactions of microbes and coral communities. The type 1 microbial reefs grew in both shallow- and deep-water settings, with a strong control by glacioeustasy. Type 2 microbial reefs developed in more tranquil periods, associated with common intermounds, and where only a single major regressive-transgressive sequence is recognised. Type 3 microbial reefs developed in constant deeper water conditions, generated by higher rates of subsidence in the basin, and creating an overall deepening-upward sequence. Type 4 microbial reefs recognised in the northern part of the basin have no clear counterparts in southern outcrops, but they are likely the capping strata observed in the latter area. Rugose corals allow to define a Type 5 reef, unrelated to microbial facies, and are recorded in oolitic-bioclastic backshoals or quiet inner platform settings. The presence of similar reefs in both the northern and southern parts of the basin demonstrates that conditions were not as different as previously proposed, and a lithostratigraphical, environmental uniformity occurs, which permits the analysis of different subsidence rates and glacioeustastic influence. In the Azrou-Khenifra Basin, the reefs, as well as other regional features, suggest that the basin, overall, evolved from an extensional tectonic regime during the early Brigantian into a complex extensional or compressional regime during the early Serpukhovian, passing into a predominantly compressional phase during the late Serpukhovian in a polyphase tectonic inversion during the onset of the Variscan Orogeny in the region.Publication Coral assemblages of the Serpukhovian–Bashkirian transition from Adarouch (Morocco)(Springer, 2022-02-16) Rodríguez García, Sergio; Said, Ismail; Somerville, Ian D.; Cózar Maldonado, Pedro; Coronado Vila, IsmaelThe Carboniferous outcrops from Adarouch (central Morocco) are composed of siliciclastic and carbonate rocks, and the latter have yielded abundant fossils. The upper part of the marine succession in the Idmarrach Formation and its laterally equivalent Tirhela Formation belong to the Bashkirian. More recent investigations of poorly preserved coral assemblages from the upper part of Idmarrach 2 section and the upper part of the Tirhela Formation are here described. The assemblage from the upper Idmarrach Formation comprises several typical Mississippian taxa, such as Aulophyllum fungites, Dibunophyllum bipartitum, Koninckophyllum interruptum, Siphonodendron scaleberense and Lithostrotion decipiens, and some highly evolved forms previously undescribed of Mississippian genera such as Haplolasma sp., Arachnolasma sp., Siphonodendron sp., Diphyphyllum sp., Solenodendron sp., Clisiophyllum sp. and a new species Corwenia tirhelensis sp. nov. In addition, an undetermined petalaxid has been also recorded. Similarly, the assemblage from near the top of the Tirhela Formation yielded some species regarded usually as Mississippian, such as Palaeosmilia murchisoni and Lithostrotion decipiens. We also identified the long-ranging tabulate Syringopora sp., Corwenia tirhelensis sp. nov., and a single species of the fasciculate rugosan, Siphonodendron tindoufense, previously described from Bashkirian rocks in the Tindouf Basin (southern Morocco). The presence of the latter taxon in both the Idmarrach and Tirhela sections implies a communication between the Adarouch region and the Saharan basins. The occurrence of S. tindoufense at the approximately same stratigraphic level in Tindouf, Taoudenni, Reggan-Ahnet and Adarouch, demonstrates its important regional stratigraphic value in North Africa.Publication Corals from Asturian substage in Cantabrian Mountains: A review(International Union of Geological Sciences, 2022) Rodríguez García, Sergio; Coronado Vila, Ismael; Rodríguez Castro, IsabelThe subdivision of the Pennsylvanian divided the Namurian, Westphalian and Stephanian regional stages in substages named with letters. During the second half of the 20th Century, some of these substages were more properly defined. Westphalian A, B and C were defined as Langsettian, Duckmantian and Bolsovian. The Stephanian A was renamed as Barruelian and the transition between Westphalian and Stephanian as Cantabrian. The Westphalian D, defined in continental strata from Saar-Lorraine, was proposed to be substituted by the Asturian substage with the stratotype in the Cantabrian Mountains. An extensive documentation with assemblages and stratigraphic distribution of plants, fusulinids, brachiopods, corals, molluscs and ostracods was presented. But a formal definition of the stratotype was never proposed. The Asturian substage in the Cantabrian Mountains comprises both marine and terrestrial strata rich in fossils and allows easy correlations with other areas. Recent studies have improved the stratigraphic data and the knowledge on the coral assemblages, mainly in the eastern area of Asturias and Palencia. The entire coral assemblage from Asturian substage in the Cantabrian Mountains is composed of 48 named species and 20 species described in open nomenclature. The short stratigraphic range of many of them may be the basis for the characterization of the Asturian stage with corals. Although some species are endemic in the Cantabrian Mountains, there are some species that are also present in other regions of the Palaeotethys. At the generic level there are significant similarities that should be the basis for wider correlations with North America and East Asia.Publication Crystallographic orientations of structural elements in skeletons of Syringoporicae (tabulate corals, Carboniferous): Implications for biomineralization processes in Palaeozoic corals(Paleontological Society, 2015-01) Coronado Vila, Ismael; Rodríguez, Sergio; Perez-Huerta, Albertohe crystallographic orientation of structural elements in skeletons of representatives of Carboniferous Syringoporicae (Auloporida) has been analysed by scanning electron microscopy (SEM), petrographic microscopy and electron backscatter diffraction (EBSD) on specimens from the Iberian Peninsula. The skeletons of the tabulate corals of the Syringoporicae consist of biogenic calcite crystals, and their microstructure is composed of lamellae, fibres and granules, or of a combination of these. Independent of the microstructure, the c-axis is oriented towards the lumen, quasi-perpendicular to the growth direction of the skeleton (perpendicular to the morphological axis lamellae, parallel to fibres). Most phaceloid taxa have a turbostratic distribution, as a biogenic response to prevent the cleavage of crystals. Cerioid and some phaceloid corals, whose microstructure is conditioned by wall elements, do not exhibit turbostratic distribution. Wall elements are determined by the biology of each taxon. Holacanth septal spines are composed of fibres arranged in a cone-shape structure, sometimes clamped to the external part of the corallite and show a complex crystallography. Monacanth septal spines are spindle shaped and composed of bundles of fibres. Tabulae are composed of lamellae. Their development and crystallographic orientation depends on the position of the epithelium in each case. Shared walls are formed by a combination of the walls of two independent corallites with a median lamina, composed of granules; these have a crystallographic orientation between that of the two corallites. The growth of the microstructure is derived by a coordinated stepping mode of growth, similar to other groups of organisms such as molluscs and scleractinians. The nucleation and formation of packages of co-oriented microcrystals suggest a growth mode similar to mineral bridges with a competitive growth mode between each crystal. The growth pattern of corallites suggests that the growth direction is divided into two main components: a horizontal growth direction towards the lumen and a vertical direction towards the top.Publication Diagenetic and Biological Overprints in Geochemical Signatures of the Gigantoproductus Tertiary Layer (Brachiopoda): Assessing the Paleoclimatic Interpretation(Multidisciplinary Digital Publishing Institute, 2023) Mateos Carralafuente, José Ricardo; Coronado Vila, Ismael; Cruz Martínez, Juncal; Cózar Maldonado, Pedro; Fernández Martínez, Esperanza; Rodríguez, SergioVariations in the geochemical signatures of fossil brachiopod shells may be due to diagenesis and/or biological processes (i.e., ‘vital effects’). It is critical to characterise them in order to identify reliable shell areas suitable for paleoclimate studies. This investigation contributes to an in-depth understanding of geochemical variations in Gigantoproductus sp. shells (SW Spain, Serpukhovian age), throwing light onto the Late Paleozoic Ice Age interpretation. Microstructural, crystallographic, cathodoluminescence and geochemical (minor and trace elements, δ18O, δ13C, and strontium isotopes) characterisations have been performed on the tertiary layer of the ventral valve, to assess the preservation state. Poorly preserved areas exhibit microstructural and geochemical changes such as recrystallisation, fracturing and higher Mn and Fe enrichment. Moreover, these areas have a higher dispersion of ⁸⁶Sr, ⁸⁷Sr, δ18O and δ13C than well-preserved areas. Three structural regions have been identified in well-preserved areas of the ventral valve by differences in valve curvature and thickness, such as the umbonal and thick and thin regions. These regions have different proportions of Mg, S, Na, δ18O, and δ13C, which are interpreted as ‘vital effects’ and probably related to growth-rate differences during shell growth. The Gigantoproductus tertiary layer seems the most suitable for paleoclimate studies, because it retains the original microstructure and geochemical composition.Publication Earthworm granules: A model of non-classical biogenic calcium carbonate phase transformations(Elsevier, 2023-05) Mandera, Sara; Coronado Vila, Ismael; Fernández Díaz, Lurdes; Mazur, Maciej; Cruz, Juncal A.; Januszewicz, Bartomiej; Fernández Martínez, Esperanza; Cózar Maldonado, Pedro; Stolarski, JaroslawDifferent non-classical crystallization mechanisms have been invoked to explain structural and compositional properties of biocrystals. The identification of precursor amorphous nanoparticle aggregation as an onset process in the formation of numerous biominerals (crystallization via particle attachment) constituted a most important breakthrough for understanding biologically mediated mineralization. A comprehensive understanding about how the attached amorphous particles transform into more stable, crystalline grains has yet to be elucidated. Here, we document structural, biogeochemical, and crystallographic aspects of the formation as well as the further phase transformations of the amorphous calcium carbonate particles formed by cultured specimens of earthworm Lumbricus terrestris. In-situ observations evidence the formation of proto-vaterite after dehydration of earthworm-produced ACC, which is subsequently followed by proto-vaterite transformation into calcite through nanoparticle attachment within the organic framework. In culture medium spiked with trace amounts of Mn2+, the cauliflower-like proto-vaterite structures become longer-lived than in the absence of Mn2+. We propose that the formation of calcite crystals takes place through a non-classical recrystallization path that involves migration of proto-vaterite nanoparticles to the crystallization site, and then, their transformation into calcite via a dissolution-recrystallization reaction. The latter is complemented by ion-by-ion crystal growth and associated with impurity release. These observations are integrated into a new model of the biocrystallization of earthworm-produced carbonate granules which highlights the sensibility of this process to environmental chemical changes, its potential impact on the bioavailability of contaminants as well as the threat that chemical pollution poses to the normal development of its early stages.Publication Estudio preliminar de las mineralizaciones de Vanadatos de Uranio asociadas a dientes y huesos fósiles: Implicaciones genéticas y geoquímicas(Sociedad Española de Mineralogía, 2010-09) Cruz Martínez, Juncal; Coronado Vila, Ismael; Fernández Díaz, LurdesPublication Far-field correlation of palaeokarstic surfaces in Mississippian successions using high-frequency foraminiferal diversity trends(Elsevier, 2022-09-01) Cózar Maldonado, Pedro; Somerville, Ian D.; Hounslow, Mark W.; Coronado Vila, IsmaelThe degree to which emergent surfaces are correlated in late Asbian carbonate successions in Britain and Ireland is assessed by the integration of detailed biostratigraphy and diversity trends in foraminifers. Data are related to the Trowbarrow Quarry section in northern England, which provides a reference section for the upper Asbian because of its rich assemblages and high sampling density. Diversity trends are shown to be non-random, possess cyclic behaviour, and can be quantitatively correlated between sections. The assemblages allow stratigraphic segmentation into 13 intervals of foraminiferal diversity trends, which sub-divide the coarser-resolution biozones and sub-biozones. Similar foraminiferal trends are recognised in sections hundreds of kilometres away from Trowbarrow, in South Wales, and southeastern and western Ireland, facilitating a more precise correlation of strata. These highlight the coeval nature of emergent surfaces and rhythms between these regions, thus, establishing a precise stratigraphy. This new assessment also enables better discrimination of ‘missing beats’ and large hiatuses in the successions. The establishment of this rhythmic stratigraphy permits recognition of the late occurrence of some biostratigraphical markers, enabling amendment of biostratigraphic mismatches.Publication Foraminifers and conodonts in the Danlu section, South China: implications for the Viséan–Serpukhovian boundary (Mississippian)(Cambridge University Press, 2023) Liu, Chao; Cózar Maldonado, Pedro; Coronado Vila, Ismael; Liang, Tian; Liu, Xiaoxiao; Chen, Hao; Li, Xin; An, Haihua; Zhang, FukaiThe Viséan–Serpukhovian boundary is poorly defined in South China, hampering regional and global stratigraphical correlations. The foraminiferal and conodont distribution of the Baping Formation in the carbonate-slope Danlu section permits the recognition of an interval from the middle Viséan to the uppermost Serpukhovian in a continuous succession. The base of the Serpukhovian in Danlu is recognized by the first occurrences of Janischewskina delicata, Howchinia subplana and questionable ‘Millerella’ tortula. At a slightly younger level, the conodont Lochriea ziegleri is first recorded. A calibration on the first occurrence of L. ziegleri in different basins at a global scale has been revised compared to auxiliary markers within the ammonoids and foraminifers. The late occurrence of L. ziegleri in the Danlu section also supports a lack of synchronicity in the global first occurrence of this taxon. This study calls for the recognition of a new base for the Serpukhovian under a far better correlation between different zonal schemes and fossil groups.Publication GEODIVULGAR: Geología y Sociedad(2021-06) García Frank, Alejandra; Canales Fernández, María Luisa; Muñoz-García, María Belén; González Acebrón, Laura; Rodríguez García, Sergio; Alonso-Zarza, Ana María; Martínez Gutiérrez, Gemma; Herrero Domínguez, Santiago; Cózar Maldonado, Pedro; Calonge García, María Amelia; Gómez Heras, Miguel; Fraguas Herráez, Ángela Raquel; Henriques, María Helena Paiva; Coronado Vila, Ismael; Díaz Megías, Isabel; Alonso Recio, Carlos; Navarro Terrón, Esther; Alonso García, Rocío; Sánchez Fontela, Noelia; Gamarra González, Jesus; Mateos Carralafuente, José Ricardo; Acedo Peñato, Abel; García Peco, Víctor; Ozkaya de Juanas, Senay Amalia; Sanz Pérez, Dánae; Cambronero García-Miguel, Irene; Galán Casado, José Miguel; Chiri Pérez, Oliver; Gómez-Escalonilla Canales, Víctor; Oliete Puertas, Elena; García Osuna, David; Vega Carricondo, Alejandro; Martín Aguilar, Lourdes; Carvajal de Lago, Alba María; Corbalán García, Judit; Portales Núñez, Killian; Montesinos del Valle, Mercedes; Gamallo Paz, Isabel; Armendáriz Sanz, Andrés; Vitón García, Íñigo; Salas Herrera, Javier; Cervilla Muros, Miguel Ángel; Iglesias Álvarez, Núria; Hontecillas Tamayo, Daniel; Pérez Garrido, Carlos; Fesharaki, Omid; Díez García, Irene Pilar; Rodrigo Sanz, Ana; del Moral González, Begoña; Mediato Arribas, José Francisco; Pérez Martín del Campo, Daniel; Chicote Alvira, Gabriel; López Martín, Valle; Campos Millán, Eduardo; Fajardo Portera, Pilar; Nacenta Torres, Pablo; Rodríguez García de Castro, Isabel; Salazar Ramirez, Roselis WaikiriaPublication Geodivulgar: Geología y Sociedad(2023-07-07) García Frank, Alejandra; Acedo Peñato, Abel; Alonso Zarza, Ana Maria; Alonso Garcia, Rocio; Armendáriz Sanz, Andrés; Berrocal Casero, Mélani; Calonge García, Mª Amelia; Cambronero García-Miguel, Irene; Campos Millán, Eduardo; Canales Fernandez, María Luisa; Carvajal De Lago, Alba María; Cazorla Bermejo, Miguel; Cernadas Garrido, Antonio; Cervilla Muros, Miguel Ángel; Chicote Alvira, Gabriel; Chiri Pérez, Oliver; Corbalán García, Judit; Coronado Vila, Ismael; Cózar Maldonado, Pedro; Del Moral González, Begoña; Diaz Megias, Isabel; Díaz Olías, Ana; Díez García, Irene Pilar; Esteve Serrano, Jorge Vicente; Fajardo Portera, Pilar; Fesharaki, Omid; Fraguas Herráez, Ángela Raquel; Fuentes Rodriguez, María; Gamallo Paz, Isabel; Gamarra González, Jesús; García Martín, Gema; García Peco, Víctor; Gómez Recio, Marta; Gómez Heras, Miguel; González Acebrón, Laura; Gutiérrez Gálvez, María; Henriques, Maria Helena Paiva; Herrero Maire-Richard, Laura; Herrero Dominguez, Santiago; Hontecillas Tamayo, Daniel; Iglesias Álvarez, Núria; Martín Perea, David Manuel; Martín Aguilar, Lourdes; Martínez Álvarez, Leyre; Martínez Gutiérrez, Gemma; Mateos Carralafuente, José Ricardo; Mediato Arribas, José Francisco; Mejía Ruiz, Irene; Molero Monsonis, Andrea; Montesinos Del Valle, Mercedes; Moreno Muñoz, Alberto; Muñoz García, María Belen; Nacenta Torres, Pablo; Navarro Terrón, Esther; Oliva Martín, Anabel; Ozkaya De Juanas, Senay; Portales Núñez, Killian; Quesada García, Álvaro; Rodrigo Sanz, Ana; Rodríguez García, Sergio; Rodríguez García De Castro, Isabel; Romero García, Santiago Alejandro; Salas Herrera, Javier; Salazar Ramírez, Roselis Waikiria; Sánchez Fontela, Noelia; Sanz Pérez, Dánae; Suárez Pérez, María Gabriela; Torices Hernandez, Angélica; Vega Carricondo, Alejandro; Vitón García, Íñigo; Yubero Martínez, Miguel