A study of Coniacian-Santonian (Upper Cretaceous) gastropod fauna was carried out on two sections of the Cap-Estérias region, which belongs to the Gabonese Coastal Basin. This study led to the identification of eight gastropod genera, including four species, that were previously unknown in this region. The genera Akera Müller, 1776, Latirus Montfort, 1810, and Fasciolaria Lamarck, 1799, as well as the species Turritella aff. rigida Sowerby, 1835, and ?Voluta (Aulica) stromboides Munier-Chalmas, 1881 are reported for the first time from the Gabonese Coastal Basin. Similarly, the stratigraphic range of the genera Voluta and ?Nerita in the Gabonese Coastal Basin is extended to the Santonian.
Thallium (Tl) is a non-essential element for living beings and is a ubiquitous metal in the Earth's crust, with an average concentration of approximately 0.5 mg/kg. This metal is commonly recovered as a byproduct during the processing of pyrite concentrates and polymetallic sulfides (Cu-Pb-Zn). Tl may exhibit a high potential for cytotoxicity and genotoxicity to humans in its two major oxidation states (I and III). The Tl content of soils and surface waters is strongly conditioned by the geological substrate. Although surface concentrations of Tl in soils range between 0.1 and 2 mg/ kg, elevated concentrations of Tl found in the Earth's crust are associated with sulfides or potassium-rich minerals. The weathering of rocks rich in these minerals leads to increasing levels of this metal in soils, waters and sediments. The present study examines the origin, mobility and ultimate fate of Tl in areas affected by acid mine drainage in the Iberian Pyrite Belt, one of the most significant polymetallic massive sulfide districts globally.
An effective way to teach basic Geoscience concepts is in field-based Geology courses. However, it is not always possible to perform this type of teaching, or it is done in very short campaigns. The objective of this study has been to search for a palliative to this problem through an accessible alternative in the form of a new YouTube channel specifically designed to teach Geology in the field. The study method consisted of producing 43 Geology-in-the-field videos over seven years using modern cinematographic techniques, high-level geological exploration and research methodologies, geological teaching scripts, specifically designed for intermediate educational levels that can be understood by a general public. In this work we include interesting technical details about the scripts, cinematographic resources, settings, lighting, sound, field filming and editing and editing of geological dissemination videos. The numerical results of the YouTube channel entitled "Geologia en el campo" are 46 videos, more than 1,417,686 views, 96,423 hours of viewing, 23,316 subscribers plus hundreds of grateful comments, especially from Spanish-speaking countries.
The record of sea-level changes during the interglacials of the last 450 ka, (MIS-5, MIS-7, MIS-9 and MIS-11) is analyzed. Based on the knowledge obtained over the last 40 years, the sequences studied on the peninsular and insular Mediterranean coast are compared with the established sea level curves, allowing the calculation of vertical movement rates for each area. The comparison of these rates with those obtained in other areas of the Iberian Peninsula indicates that the highest uplift rates are recorded in Gibraltar, decreasing both eastwards and westwards, with another maximum at Cape San Vicente. This higher uplift trend is conditioned by the proximity to the boundary between the Iberian and Nubian microplate. The highest uplift rates on the Mediterranean coast are recorded in sequences locally affected by active faults associated to the Eastern Betic Shear Zone, and specifically to its southern and northern terminal splays. The rates calculated on the peninsular Mediterranean coasts for MIS-5, 9 and 11 show a moderate uplift with maxima never exceeding 0.1 mm/yr. The values calculated for MIS-7 generally show higher values (<0.2mm/yr) incongruent with those calculated for each sequence. The calculated rates for Mallorca (Campo de Tiro, Cala Blava) show a slight uplift or stability.
The Gredos massif occupies the central part of the Spanish Central system batholith. It primarily comprises calc-alkaline granodiorites and monzogranites rich in alkalis, with lesser amounts of leucogranitic and basic rocks. In areas where detailed studies have been conducted, the intrusive units form tabular bodies emplaced within the metamorphic rocks that constituted the mid-crust during the Late Carboniferous, remaining as septa of metasediments and migmatites between the intrusive sheets. The recent history of uplift and glaciation in the Si erra de Gredos has exposed many of these plutonic and metamorphic rocks, revealing excellent outcrops that provide opportunities to observe world-class examples of magmatic processes at the emplacement level. The study of field relations in outcrops such as the Gredos massif has enabled an in-depth discussion on the origin of magmatic fabrics and structures, the observation of the variety of enclave types and how these contribute to a deeper understanding of petrogenetic and rheological aspects, as well as a more precise interpretation of the interaction (assimilation) processes between intrusive magmas and the host metasediments. This work represents a journey into the crust where all these magmatic processes occurred, highlighting their main characteristics based on field relationships and supported by geochemical, petrological, structural, experimental, and geochronological evidence.
The generic name of roofing slate is used to describe a series of metamorphic rocks whose main characteristic is that they can be cleaved into thin, flat plates, ideal for use as roof coverings. The construction possibilities ofthese rocks have meant that they have been used since prehistoric times, although the oldest documented evidence dates back to the Roman Empire. Over the centuries, the slate industry shaped and defined the extraction regions. In Europe, the use of these rocks was of great importance from the Middle Ages to the mid-twentieth century in countries such as France, the United Kingdom and Germany. The centuries-old exploitation of the Central European deposits led to their progressive depletion. In the mid-1960s, the deposits in northwestern Spain burst onto the world market, monopolizing it. The production process for roofing slate has been incorporating the technological advances in the extraction of ornamental rock in recent centuries, although it remains relatively simple. Roofing slate is extracted from the rock mass, exfoliated and cut according to predefined formats, and is then ready for use without further modifications. This paper reviews the chronology of this material worldwide. It also defines the characteristics of the different types of roofing slate, as well as its current extraction areas and production process, detailing the applied aspects of teaching this industry in secondary education.
The Meteorite Collection of the National Museum of Natural Sciences in Madrid houses several specimens of historical significance. Among these, the Madrid Meteorite (17167/MET-E-28) stands out, with its fall thoroughly documented in 1896. Scientific investigation of this specimen began in the same year and was expanded in subsequent decades through the application of various analytical techniques. Non-destructive methods have been particularly advantageous, as they ensure the long-term preservation of such unique material. The correlated application of these techniques to a specific region of the meteorite, combined with a full micro-computed tomography scan, enabled the confirmation of extra-terrestrial phosphates and evidence of impact-induced thermal processes. This case study demonstrates the effectiveness of integrating complementary analytical approaches, supported by the use of a reference marker, to enhance the structural and compositional analysis of rare meteoritic samples.
This article presents a characterization of the four bezoar stones preserved in the Geology and Fine Arts collections of the National Museum of Natural Sciences of Madrid (MNCN). First of all, a precise definition of these curious mineral samples generated in the digestive processes of ruminant mammals has been sought, and then the presence of these artfacts in the collections of the aforementioned museum has been placed in their historical context. In this sense, historiographic sources have been sought, especially those coming from the historical chroniclers ofAmerica, to explain the interest in bezoar stones of naturalists, collectors and scholars of both medicine and pharmacological products of popular tradition (Ars Medica). Two of the bezoar stones studied are set in silver, so that, in addition to being geological goods, they can also be classified as objects of the decorative arts. From this perspective, and for the first time, the goldsmith marks detected in the silver settings have been analyzed to determine their place and date of manufacture. Special em phasis is placed on the analyses carried out by non-destructive laboratory techniques by Professor Javier Garcia Guinea, which have made it possible to clarify the chemical and mineral components of these specimens. The last section of this work focuses on the comparison of the MNCN specimens with those from other European museums.
The Historical Collection of Feldspars at the Museo Nacional de Ciencias Naturales (MNCN-CSIC) began its formation with the founding and development of the Real Gabinete de Historia Natural (RGHN) in the mid-18th century, in the context of the Age of Enlightenment, at the dawn of the development of feldspar mineralogy and terminology. The collection grew and was later improved during the 19th and early 20th centuries. It currently consists of 324 mineral specimens, with feldspars being the main mineral phase. Thanks to the handwritten documents available in the Archivo Hist & oacute;rico MNCN, we can trace the history of the collection's formation and its protagonists. Several historical specimens stand out in the collection, such as the Labrador Stone (labradorite), the adularia from the Alps, and the large potassium feldspar crystals and twins from Bustraviejo (Madrid). In addition, we document historical and mineralogical details of the "valencianite" specimens from the Valenciana mine, Guanajuato (Mexico), a mineral that has recently been proposed as a new mineral species in the group of potassium feldspars.
La Colección Histórica de Feldespatos del Museo Nacional de Ciencias Naturales (MNCN-CSIC) empezó a formarse con la fundación y el desarrollo de Real Gabinete de Historia Natural (RGHN) a mediados del siglo XVIII, en el contexto de la Ilustración, en los inicios del desarrollo de la mineralogía y la terminología de los feldespatos. La colección creció y mejoró más tarde durante el siglo XIX y principios del siglo XX, con diversos aportes. Actualmente, consta de 324 ejemplares minerales con los feldespatos como fase principal. Gracias a los documentos manuscritos, disponibles en el Archivo Histórico del MNCN, podemos trazar la historia de la formación de la colección, y sus protagonistas. En la colección destacan varios ejemplares históricos, como la Piedra de Labrador (labradorita), las adularias de los Alpes, y los grandes cristales y maclas de feldespato potásico de Bustraviejo (Madrid). Finalmente, se presentan detalles históricos y mineralógicos de los especímenes de “valencianita” de la mina Valenciana, Guanajuato (Méjico), mineral que ha sido propuesto, recientemente, como una nueva especie mineral en el grupo de los feldespatos potásicos.
El macizo de Gredos ocupa la parte central del batolito del Sistema Central español. Está constituido principalmente por granodioritas y monzogranitos de afinidad calco-alcalina, ricos en álcalis, con cantidades menores de rocas leucograníticas y básicas. Donde se han estudiado con detalle, las unidades intrusivas forman cuerpos tabulares emplazados en las rocas metamórficas que conformaban la corteza media en el Carbonífero tardío, que quedan como septas de metasedimentos y migmatitas entre las láminas intrusivas. La historia reciente de levantamiento y glaciarismo en la Sierra de Gredos ha permitido que muchas de sus gargantas y laderas expongan excelentes afloramientos rocosos que ofrecen la oportunidad de observar ejemplos de interés mundial de procesos magmáticos en el nivel de emplazamiento. El estudio de las relaciones de campo en afloramientos como el del macizo de Gredos ha permitido discutir en profundidad el origen de las fábricas y estructuras magmáticas, observar la variedad de tipos de enclaves y como estos ayudan a profundizar en aspectos petrogenéticos y reológicos, o interpretar más precisamente los procesos de interacción (asimilación) entre los magmas intrusivos y los metasedimentos encajantes. Este trabajo representa un viaje al interior de la corteza donde se produjeron todos estos procesos magmáticos, mostrando sus principales características basandonos en las relaciones de campo, y apoyados en otro conjunto de evidencias geoquímicas, petrológicas, estructurales, experimentales y geocronológicas.
En este artículo se plantea una caracterización de las cuatro piedras bezoares conservadas en las colecciones de Geología y Bellas Artes del Museo Nacional de Ciencias Naturales de Madrid MNCN). En primer lugar, se ha buscada una definición precisa de estas curiosas muestras minerales generadas en los procesos digestivos de los mamíferos rumiantes, para a continuación poner en su contexto histórico la presencia de estos objetos en las colecciones del citado museo. En este sentido, se han buscado las fuentes historiográficas, sobre todo las procedentes de los cronistas históricos de América, para explicar el interés por las piedras bezoares de los naturalistas, los coleccionistas y los estudiosos tanto de la medicina como de los productos farmacológicos de tradición popular (Ars Medica). Dos de las piedras bezoares estudiadas están engarzadas en plata, es por ello que además de bienes geológicos también se pueden clasificar como objetos del campo de las artes decorativas. Es desde esta perspectiva, y por primera vez, que se han analizado las marcas de orfebre detectadas en los engarces de plata para determinar su lugar de fabricación y la fecha de su manufactura. Se pone especial énfasis en las analíticas realizadas mediante técnicas de laboratorio no destructivas por el profesor Javier García Guinea, que han permitido aclarar cuáles son los componentes químicos y minerales de estos ejemplares. El último apartado de este trabajo se centra en comparar los ejemplares del MNCN con otras piedras bezoares conservadas en otros museos europeos.
Se analiza el registro de los cambios del nivel del mar a lo largo de los interglaciares ocurridos en los últimos 450 ka, correspondientes a los MIS-5, MIS-7, MIS-9 y MIS-11. A partir del conocimiento obtenido a lo largo de los últimos 40 años, se comparan las secuencias estudiadas en el litoral mediterráneo peninsular e insular, con las curvas del nivel del mar establecidas, lo que permite calcular tasas de movimiento vertical para cada zona. La comparación de estas tasas con las obtenidas en otras zonas de la península ibérica indica que las mayores tasas de levantamiento se registran en el estrecho de Gibraltar disminuyendo tanto hacia el este como hacia el oeste, con un nuevo máximo en el Cabo de San Vicente. Esta tendencia al levantamiento está condicionada por la cercanía al límite entre la microplaca ibérica y la nubia. Las mayores tasas de levantamiento en la costa mediterránea se registran en secuencias afectadas localmente por fallas activas asociadas a la zona de desgarre de las béticas orientales y, en concreto, a sus aperturas terminales meridional y septentrional. Las tasas calculadas en las costas mediterráneas peninsulares para los MIS-5, 9 y 11 muestran un levantamiento moderado, con máximos que nunca sobrepasan los 0,1 mm/año. Los valores calculados para el MIS-7 por lo general muestran valores más altos (<0,2 mm/año) incongruentes con los calculados para cada secuencia. Las tasas calculadas para Mallorca (Campo de Tiro, Cala Blava) muestran un ligero levantamiento o estabilidad.
A brief review is provided of the applications of lithium mineral resources for the manufacture of vitreous materials: glass, enamels, and glass-ceramics. First, are reviewed the general situation regarding lithium applications in other fields of products and main sources of lithium-containing minerals and rocks are also reviewed. It is shown and described the pioneer research conducted in Spain in last decades for the crystallization of glasses in the Li₂O-SiO₂ binary system, without and with oxide nucleating agents, as well as the use of this basic system for the formulation of new glasses and glass-ceramics with applications as neutron absorbent materials. Otherwise, it is reviewed the results in the obtaining of those vitreous materials formulated from Spanish and Portuguese lithium minerals of amblygonite, lepidolite, vermiculite, and muscovite mining wastes. Main conclusion it was that is possible to obtain aventurine glass-ceramics where is formed a new lithium phosphate spodumene with surface segregation of iron oxides. Finally, the main future prospects in this field are discussed.
La Colección de Meteoritos del Museo Nacional de Ciencias Naturales de Madrid alberga en sus fondos diversos ejemplares de origen histórico. Entre ellos destaca el denominado Meteorito de Madrid (17167/MET-E-28) cuya caída fue documentada ampliamente en 1896. El estudio de este ejemplar comenzó en el mismo año de su caída y se fue ampliando en décadas posteriores empleando distintas técnicas, siendo las no destructivas las más adecuadas para asegurar la preservación de un ejemplar de este tipo. La aplicación de este tipo de técnicas de forma correlativa en una zona concreta del meteorito junto con una microtomografía del ejemplar completo, ha permitido corroborar la presencia de fosfatos de origen extraterrestre, así como los procesos de calentamiento por impacto sufridos por el mismo. De esta forma se muestra la utilidad de combinar de modo correlativo las capacidades de distintas técnicas mediante el empleo de un marcador de referencia al estudio de un ejemplar.
Una buena manera de enseñar conceptos básicos de Geología es mediante cursos impartidos en el campo. Sin embargo, no siempre es posible hacer este tipo de docencia, o se realiza en campañas muy cortas. El objetivo de este estudio ha sido la búsqueda de un paliativo a este problema a través de videos educativos diseñados para enseñar Geología en el Campo, disponibles a través de un canal de YouTube. El método de estudio ha consistido en elaborar 43 vídeos de geología-en-el-campo, durante siete años, utilizando técnicas cinematográficas modernas, metodologías de exploración e investigación Geológica y guiones didácticos de Geología, específicamente diseñados para niveles educativos intermedios que puedan ser entendidos por el público general. En este trabajo incluimos detalles técnicos sobre guionización, recursos cinematográficos, escenarios, iluminación, sonido, filmación en campo y montaje y edición de vídeos de divulgación Geológica. Los resultados numéricos del canal YouTube “Geología en el campo” son 46 vídeos, más de 1.417.686 visualizaciones, 96.423 horas de visualización, 23.316 suscriptores junto con centenares de comentarios agradecidos, sobre todo desde países de habla hispana.
In recent years, elevated concentrations of arsenic (As) have been detected in the Tertiary detrital aquifer of Madrid. A significant number of areas where waste from old mining operations, rich in metals and metalloids, accumulate may partially explain contamination events by toxic elements. In these environments, colloidal particles can act as nanovectors for the dispersion of As, enhancing its migration and contamination of surrounding soils. This work studies the mobilization of As-rich colloids from a waste zone of an old mining operation in the Community of Madrid. These wastes, mainly composed of arsenopyrite [FeAsS] ([As] = 0.2 g kg-1), are deposited near a natural stream and exposed to environmental conditions. In order to follow the mobility of As-rich colloids, the combined techniques of asymmetric flow field flow fractionation and inductively coupled plasma mass spectrometry (AF4-ICP-MS) are used to obtain the size distribution of the colloidal fraction and associated As, while X-ray absorption spectroscopy (XAS) techniques are utilized for the study of the chemical speciation of As in the solid phase. In addition, geochemical modeling allows prediction of the thermodynamically favored phases in each of the studied areas. The mobilization of colloidal As from mining waste to water and soil located up to 1 km from the source of contamination is described. The essential role of colloidal Fe oxyhydroxides as As mobilizing nanovectors is also highlighted.
Luminescence emission is observed from many minerals and it provides important information about the physical and chemical processes taking place in both inorganic and biogenic materials (silicates, carbonates, phosphates, etcetera). It is equally valuable for geological and archaeological dating, detection of irradiated foods, or retrospective applications. Examples described here emphasize some of the career successes of Prof. Dr. Javier García Guinea who has advanced the topic with major contributions to the fields of physics and chemistry of minerals by the study of luminescent emission from natural materials. Geological materials are particularly challenging, as they are highly variable, thus, it has been an achievement to understand the underlying processes and his dedication and expertise have greatly influenced the fields of luminescence spectroscopy and its applications in geosciences, material sciences, retrospective dosimetry and biomedical engineering. He has inspired and guided many researchers, and will undoubtedly continue to do so into his retirement.
Climate models predict an increase in extreme hydrological events (droughts and floods) as global temperatures respond to anthropogenic increases in greenhouse gases. This change in the pattern of extreme events due to global climate change raises uncertainties in assessing the risk of future droughts and floods. Conventionally, this problem has been addressed from a “top-down” approach based on downscaling of climate models. The development of this approach generates a high uncertainty that, in practice, does not allow determining in a reasonable and operational manner the magnitude of the change. Recently, it has been proposed to move towards a “bottom-up” approach of progressive adaptation to change based on the experience of recent events. It is assumed that future climate change will not create entirely new types of extreme weather events that have never before occurred on the planet. In this work, we review the main paleo-records (geological and botanical), which allow us to characterize and quantify hydrological extremes and their relation to climate variability at multi-decadal and secular time scales. This information is relevant to advance in the adaptation to extreme events in the context of climate change, particularly in the design of infrastructures, urbanism and territorial planning.
