Person: Suárez González, Pablo
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First Name
Pablo
Last Name
Suárez González
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Geodinámica, Estratigrafía y Paleontología
Area
Estratigrafía
Identifiers
9 results
Search Results
Now showing 1 - 9 of 9
Item Revisiting the phosphorite deposit of Fontanarejo (central Spain): new window into the early Cambrian evolution of sponges and the microbial origin of phosphorites(Geological magazine, 2021) Reitner, Joachim; Luo, Cui; Suárez González, Pablo; Duda, Jan-PeterFossils within early Cambrian phosphorites worldwide are often well preserved due to early diagenetic permineralization. Here, we examine the fossil record contained within phosphorites of the Lower Cambrian Pusa Formation (late Fortunian to Cambrian Stage 2) in Fontanarejo, central Spain. The sedimentology and age of these phosphorites have been controversial and are here reviewed and discussed, providing also an updated geological map. The Pusa Formation is composed of fine clastic sediments that are partly turbiditic, with channels of quartz-rich conglomerates and abundant phosphorites in the upper part of the succession. The microfacies and mineralogy of these channel deposits are studied here for the first time in detail, showing that they are mainly composed of subspherical apatite clasts, with minor mudstone intraclasts, quartzite and mica grains. Numerous sponge spicules, as well as entirely preserved hexactinellid sponges and demosponges, were collected within these phosphorites and likely represent stem groups. In addition to sponges, other fossils, such as small shelly fossils (SSF) of the mollusc Anabarella sp., were found. The phosphorites exhibit multiple evidence of intense microbial activity, including diverse fabrics (phosphatic oncoidal-like microbialites, thrombolites, stromatolites and cements) and abundant fossils of filamentous microbes that strongly resemble extant sulphur-oxidizing bacteria. Our findings strongly suggest that microbial processes mediated the rapid formation of most of the Fontanarejo apatite, probably accounting for the exceptional preservation of fragile fossils such as sponge skeletons. The apparent presence of taxonomically diverse hexactinellid and demosponge communities at the lowermost Cambrian further corroborates a Precambrian origin of the phylum Porifera.Item Contrasting Modes of Carbonate Precipitation in a Hypersaline Microbial Mat and Their Influence on Biomarker Preservation (Kiritimati, Central Pacific)(Minerals, 2022) Shen, Yan; Suárez González, Pablo; Reitner, JoachimMicrobial mats represented the earliest complex ecosystems on Earth, since fossil mineralized examples (i.e., microbialites) date back to the Archean Eon. Some microbialites contain putative remains of organic matter (OM), however the processes and pathways that lead to the preservation of OM within microbialite minerals are still poorly understood. Here, a multidisciplinary study is presented (including petrographic, mineralogical and organic geochemical analyses), focusing on a modern calcifying mat from a hypersaline lake in the Kiritimati atoll (Central Pacific). The results show that this mat has a complex history, with two main growth phases under hypersaline conditions, separated by an interruption caused by desiccation and/or freshening of the lake. The mineral precipitates of the mat are predominantly aragonitic and two contrasting precipitation modes are observed: the main growth phases of the mat were characterized by the slow formation of irregular micritic particles with micropeloidal textures and subspherical particles, linked to the degradation of the exopolymer (EPS) matrix of the mat; whereas the interruption period was characterized by the rapid development of a thin but laterally continuous crust composed of superposed fibrous aragonite botryoids that entombed their contemporaneous benthic microbial community. These two precipitation modes triggered different preservation pathways for the OM of the mat as the thin crust shows a particular lipid biomarker signature, different from that of other layers and the relatively rapid precipitation of the crust protecting the underlying lipids from degradation, causing them to show a preservation equivalent to that of a modern active microbial community, despite them being >1100 years old. Equivalent thin mineral crusts occur in other microbialite examples and, thus, this study highlights them as excellent targets for the search of well-preserved biomarker signatures in fossil microbialites. Nevertheless, the results of this work warn for extreme caution when interpreting complex microbialite biomarker signatures, advising combined petrographic, mineralogical and geochemical investigations for the different microbialite layers and mineral microfabrics.Item Ice-rafted dropstones at midlatitudes in the Cretaceous of continental Iberia: Comment(Geology, 2024) Benito Moreno, María Isabel; Quijada, Isabel Emma; García Martín, Martín; Pertuz Dominguez, Alejandro; Suárez González, Pablo; Torices Hernández, Angélica; Campos Soto, SoniaItem Constraints of applying strontium isotope stratigraphy in coastal and shallow marine environments: insights from Lower Cretaceous carbonates deposited in an active tectonic setting (N Iberian Basin, Spain)(Journal of Iberian Geology, 2020) Benito Moreno, María Isabel; Suárez González, Pablo; Campos Soto, Sonia; Rodríguez Martínez, MartaThe Lower Cretaceous Leza Formation is an essentially carbonate unit deposited at the northernmost active margin of the Cameros Basin (N Spain) under an extensional tectonic regime. This unit is composed of freshwater, marine-influenced, marginal-marine and hypersaline marine carbonate facies, interbedded with variable amounts of alluvial deposits, mainly derived from the erosion of the Jurassic substrate. 87Sr/86Sr, δ18O and δ13C analyses were obtained from carbonate facies of the Eastern and Western sectors of the basin. δ18O values follow the expected trend in both sectors: they are more negative (down to − 7.9‰) in freshwater carbonates and more positive (up to + 2.8‰) in marginal-marine to hypersaline facies. However, independently of the seawater or freshwater influence, in the Western Sector the 87Sr/86Sr values (0.707373–0.707801) are significantly lower and closer to the published Lower Cretaceous seawater 87Sr/86Sr ratios, than those of the Eastern Sector (0.707988–0.709033), where the overall marine influence was relatively high and the alluvial input low. These data strongly suggest that 87Sr/86Sr ratios were mainly controlled by those of the riverine freshwater arriving to the coastal and marine areas after the weathering and erosion of the Jurassic carbonates or siliciclastic rocks, in the Western and Eastern sectors, respectively. Thus, data indicate that, in coastal and shallow marine carbonates, the influence of the riverine water on the 87Sr/86Sr ratios should be systematically evaluated. This is particularly necessary in active tectonic settings, where the uplifted areas are significantly prone to weathering and erosion and where alluvial fan systems commonly developed, eventually discharging into coastal and shallow marine areas.Item Ooids forming in situ within microbial mats (Kiritimati atoll, central Pacific)(Paläontologische Zeitschrift, 2021) Suárez González, Pablo; Reitner, JoachimOoids (subspherical particles with a laminated cortex growing around a nucleus) are ubiquitous in the geological record since the Archean and have been widely studied for more than two centuries. However, various questions about them remain open, particularly about the role of microbial communities and organic matter in their formation and development. Although ooids typically occur rolling around in agitated waters, here, we describe for the first time aragonite ooids forming statically within microbial mats from hypersaline ponds of Kiritimati (Kiribati, central Pacific). Subspherical particles had been previously observed in these mats and classified as spherulites, but these particles grow around autochthonous micritic nuclei, and many of them have laminated cortices, with alternating radial fibrous laminae and micritic laminae. Thus, they are compatible with the definition of the term ‘ooid’ and are in fact very similar to many modern and fossil examples. Kiritimati ooids are more abundant and developed in some ponds and in some particular layers of the microbial mats, which leads to the discussion and interpretation of their formation processes as product of mat evolution, through a combination of organic and environmental factors. Radial fibrous laminae are formed during periods of increased supersaturation, either by metabolic or environmental processes. Micritic laminae are formed in closer association with the mat exopolymer (EPS) matrix, probably during periods of lower supersaturation and/or stronger EPS degradation. Therefore, this study represents a step forward in the understanding of ooid development as influenced by microbial communities, providing a useful analogue for explaining similar fossil ooids.Item Columnar microbialites of the upper Miocene of Mallorca (Spain): A new morphogenetic model based on concurrent accretion and bioturbation – uncommon or overlooked?(Sedimentology, 2021) Suárez González, Pablo; Benito Moreno, María Isabel; Arenas Abad, Concepción; Pomar, LuisBioturbation has long been considered an antagonist of microbialite development and preservation, because metazoan grazing and burrowing destroy benthic microbial communities. However, metazoan bioturbation, in conjunction with microbial accretion, may have had a significant role in the morphogenesis of some columnar microbialites, as suggested by the case study presented and by some Phanerozoic and Upper Proterozoic analogues discussed here. Late Miocene in age, the studied microbial biostrome developed in a western Mediterranean restricted shallow-water platform dominated by grainy sediments and with a notable influence of bioturbation. This study is focused on the complex accretionary history of the columnar microbialite biostrome and on its striking dark grey colour, which is attributed to Mn-oxyhydroxides precipitated during meteoric diagenesis linked to subaerial exposure. The characteristic columnar structure of the microbialite biostrome has features consistent with an accretionary origin of the columns, but also has features suggesting metazoan disruption. Therefore, a new morphogenetic model for columnar microbialites is presented, highlighting the concomitant roles of microbial accretion, bioturbation and grainy sediment infill of the intercolumn space. Whether this model is an exception or a rule, should be tested on other examples of Phanerozoic and Upper Proterozoic columnar microbialites. Nevertheless, this model is a step forward in understanding the complex microbe–metazoan interactions as constructive coexistence rather than just as destructive competition.Item Challenges to carbonate-evaporite peritidal facies models and cycles: Insights from Lower Cretaceous stromatolite-bearing deposits (Oncala Group, N Spain)(Sedimentary Geology, 2020) Quijada, I. Emma; Benito Moreno, María Isabel; Suárez González, Pablo; Rodríguez Martínez, Marta; Campos Soto, SoniaPeritidal carbonate-evaporite successions, since they are developed in the transition between continental and marine realms, provide essential keys for palaeobathymetric and palaeoclimatic interpretations. As a result, several facies models have been proposed to assist on the interpretation of ancient tidal flat deposits, and peritidal successions have been extensively used for cyclicity analyses. In this study, well-exposed, Lower Cretaceous peritidal deposits (Oncala Group, Cameros Basin, N Spain) are analysed and compared with the most commonly-used present-day analogues (from Shark Bay, the Arabian Gulf and the Bahamas) and with ancient peritidal successions, providing their palaeoenvironmental and palaeoclimatic interpretation, assessing the usefulness and limitations of the facies models, and evaluating the suitability of these deposits for analysis of decimetre to metre-scale cycles. The studied peritidal deposits consist of thinly-bedded to laminated dolostones, dolomitic stromatolites, stromatolite breccias, flat-pebble and edgewise breccias, and calcite and quartz pseudomorphs after anhydrite nodules. Abundant resemblances of the peritidal deposits of the Oncala Group with those of Shark Bay, including that they are largely composed of microbialites and intraclasts, makes the peritidal deposits of the Oncala Group one of the best fossil analogues of this present-day setting. However, the presence of anhydrite nodules indicates pervasive evaporite precipitation in the supratidal zone, which is a feature that does not occur in supratidal flats of Shark Bay, but is characteristic of arid sabkhas of the Arabian Gulf. Nevertheless, the fact that carbonate-evaporite tidal flats of the Oncala Group were laterally related with siliciclastic tidal flats with large freshwater input and broadly inhabited by dinosaurs, suggests that anhydrites precipitated under less arid climates than those of the Arabian Gulf nowadays, pointing to semiarid climatic conditions during deposition. Moreover, the fact that peritidal deposits with anhydrite nodules were exclusively formed in a low-subsidence area of the Cameros Basin suggests that the rate of accommodation space creation also played an important role in their development. Regarding the comparison with other fossil peritidal sediments, the studied deposits show more abundant similarities with Proterozoic and Cambrian successions, composed mainly of stromatolites, microbial laminites, and intraclasts, than with other Mesozoic peritidal deposits, in which bioclasts and burrowing are usually more abundant. This highlights the difficulties for assigning specific features to certain geological ages. Finally, peritidal facies of the Oncala Group may change laterally and vertically to any other facies, showing a patchy lateral distribution of facies and an unsystematic vertical stacking pattern. The sedimentary features of the stromatolite, breccia and thinly-bedded to laminated dolostone facies do not allow their assignment to a unique tidal zone. Moreover, sedimentary features indicative of subaerial exposure, such as anhydrite nodules formed in the capillary zone, occur within any of the carbonate facies and show limited lateral extent. This results in a succession that cannot be clearly subdivided into subsequent shallowing-upward cycles not even by using erosive surfaces or the anhydrite nodule layers as marker horizons of the upper part of the cycles, because their limited lateral extent prevents reliable correlations. Similar composite lateral and vertical facies relationships have been documented both in the present-day analogues and in ancient successions, which suggests that this kind of facies relationships may be common in peritidal successions and highlights the caution that must be taken when trying to perform cyclicity analysis on them.Item Where humid and arid meet: Sedimentology of coastal siliciclastic successions deposited in apparently contrasting climates(Sedimentology, 2022) Campos Soto, Sonia; Benito Moreno, María Isabel; Mountney, Nigel P.; Plink-Björklund, Piret; Quijada, Isabel Emma; Suárez González, Pablo; Cobos, AlbertoDeciphering the palaeoenvironmental and palaeoclimatic setting of ancient successions that include deposits typical of different climates can be challenging. This is the case in the Late Jurassic succession cropping out in eastern Spain (South-Iberian and western Maestrazgo basins), where deposits characteristic of both arid to semiarid and humid to subhumid settings have been identified through a detailed analysis of eight stratigraphic sections. These sections comprise shallow marine carbonates changing upward and laterally to a predominantly siliciclastic coastal and alluvial succession, including abundant dinosaur remains. Deposition of coastal and alluvial sediments occurred in flood plains, ephemeral and perennial fluvial channels, aeolian dunes, deltas, distributary mouth-bars and associated distributary channels, and shallow water bodies influenced by both fresh and marine waters. Some of these deposits, notably those of aeolian and ephemeral fluvial origin, are characteristic of arid to semiarid climates. However, there are also abundant deposits that can be demonstrably shown to have a coeval origin, which are indicative of permanent water courses: (i) sediments of seasonal discharge fluvial channels with perennial to semi-perennial flow, displaying subcritical and supercritical flow sedimentary structures; (ii) deltaic sediments deposited in permanent freshwater bodies; and (iii) abundant plant and dinosaur remains, especially of herbivorous dinosaurs, which required the presence of permanent water sources and abundant vegetation. These apparently contrasting sedimentary features indicate that deposition occurred under a seasonal climate controlled by monsoonal-type precipitation. These deposits are analogous to those observed nowadays in the Lençóis Maranhenses National Park (north-east Brazil), where a subhumid tropical climate with a seasonal precipitation pattern prevails. Thus, this study shows that only through careful facies analysis and interpretation of depositional processes that can be shown to be occurring concurrently in neighbouring and related depositional systems can the detailed palaeoenvironmental and palaeoclimatic setting of complex coastal sedimentary successions be confidently reconstructed in detail.- Project number: 245
Item Aplicación didáctica mediante virtualización de afloramientos geológicos por medio herramientas digitales de muy alta resolución(2022) García Lorenzo, María De La Luz; Abati Gómez, Jacobo; Álvarez Sierra, María De Los Ángeles; Ancochea Soto, Eumenio; Arribas Mocoroa, María Eugenia; Arroyo Rey, Xabier; Benito Moreno, María Isabel; Campos Soto, Sonia; Castiñeiras García, Pedro; Crespo Feo, María Elena; Fernández Barrenechea, José María; García Romero, Emilia; Granja Bruña, José Luis; Huertas Coronel, María José; Ignacio San José, Cristina de; López De Andrés, María Sol; Martín Chivelet, Javier; Martínez Santos, Pedro; Montero González, Esperanza; Muñoz Martín, Alfonso; Orejana García, David; Pieren Pidal, Agustín Pedro; Piña García, Rubén; Sánchez Donoso, Ramón; Suárez González, Pablo; Pertuz Dominguez, AlejandroTras la situación sanitaria del curso 2019-2020 y a través del Proyecto INNOVA Gestión 223 de la convocatoria del año 2020-2021, la Facultad de Ciencias Geológicas ha adquirido una herramienta para la virtualización de afloramientos geológicos. Durante el curso 2020-2021 se ha virtualizado una salida de campo de cada uno de los grados que se imparten en la Facultad, Grado en Geología y Grado en Ingeniería Geológica. Además, la mayor parte de la actividad de campo de este curso tendrá lugar durante el mes de mayo, por lo que los profesores van a poder realizar la virtualización de sus salidas de campo mientras realizan la salida presencial con los estudiantes, o incluso en algunas asignaturas los propios estudiantes van a ser los responsables de la virtualización de las mismas. Por ello, la herramienta GIGAPAN no sólo es de elevada utilidad en momentos en los que las restricciones de movilidad impiden la realización del campo sino que también permiten aplicar metodologías docentes invertidas durante la realización de los campamentos. De este modo los estudiantes pasan a tener un papel activo en relación a su proceso de aprendizaje. La herramienta GIGAPAN permite que se combinen imágenes fotográficas de megapíxeles de alta resolución para crear imágenes panorámicas de gigapíxeles que luego se pueden explorar a muchas escalas haciendo zoom y visión panorámica. Los GigaPans son gigapíxeles panorámicos, imágenes digitales con billones de píxeles. Gigapan crea panorámicas enormes, para conseguir elevado detalle con mucha nitidez. Además de proporcionar una experiencia de aprendizaje alternativa, estos recursos permiten una visita 'virtual' que puede ser una herramienta de aprendizaje útil en cualquier escenario docente. La utilidad del material generado tiene validez más allá de la pandemia, ya que puede ser utilizado por los estudiantes en el estudio de las asignaturas de la titulación, con un enorme potencial didáctico hasta ahora poco explorado. Hasta la fecha el GIGAPAN se ha venido utilizando con cámaras personales de profesores de la Facultad, por lo que se hace necesario completar esta herramienta con una cámara compatible con el módulo que permita ser usada tanto por profesores que no dispongan de la misma como por estudiantes de la Facultad.