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.
