Mantos inducidos por microbialitas en sedimentos siliciclásticos plio-cuaternarios? Del NO de Iberia

[EN] Microbial mats are organo-sedimentary deposits formed by bacteria that trap or synthesize certain chemical elements. This type of activity gives rise to the formation of lamellar and/or columnar bioconstructions (stromatolites) and/or concentric structures (oncolites and thrombolites). The study of microbial mats used to be restricted mainly to marine and coastal environments related to the formation of ancient carbonate sediments (Palaeozoic/Proterozoic), and/or extreme conditions in hypersaline environments. However, in recent years, the presence of these forms has been identified in continental siliciclastic rocks and sediments with a temporal distribution that reaches into modern times. In this study, several levels of ferruginous crusts associated with microbial activity are found, interspersed in a Cenozoic deposit located in the province of Zamora. This deposit consists of concentric, laminated iron structures filled with silt, interspersed throughout a clayey-silt layer of variegated colors which shows signs of bioturbation and desiccation due to fluid escape. These findings allow the inference of the sedimentary and climatic conditions responsible for the growth and preservation of microbial mats in the siliciclastic sediments of the north-western edge of the Duero Basin.[ES] Los mantos microbiales constituyen depósitos organosedimentarios formados por bacterias que atrapan o sintetizan determinados elementos químicos. Este tipo de actividad da lugar a la formación de estructuras laminares y/o columnares (estromatolitos) y/o concéntricas (oncolitos y trombolitos). Su estudio, por tanto, quedaba reducido principalmente a ambientes marinos y litorales relacionados con la formación de sedimentos carbonatados de edad muy antigua (Paleozoico/ Proterozoico), y/o condiciones extremas en ambientes hipersalinos. Sin embargo, en los últimos años, se ha identificado la presencia de estas formas en rocas y sedimentos de afinidad continental y carácter siliciclástico, que se extienden temporalmente hasta la actualidad. En este estudio, se presenta el hallazgo de varios niveles de costras ferruginosas asociadas a la actividad microbiana, intercalados en un depósito cenozoico de la provincia de Zamora. Se trata de una serie de niveles caracterizados por la presencia de capas ferruginosas laminadas y concéntricas, constituidas por limos que aparecen en el techo y muro de un nivel arcilloso-limoso de colores abigarrados y signos de bioturbación y desecación por escape de fluidos. Este singular hallazgo permite establecer las condiciones sedimentarias y climáticas responsables del crecimiento y conservación de mantos microbianos en sedimentos siliciclásticos del borde noroccidental de la cuenca del DueroSIThis work was partially funded by the Projects 0284_Esmimet_3_E (Interreg V-A Programa de Cooperación España-Portugal, 2014-2020) and LE167G18 (Junta de Castilla y León, Spain)

Geotourism and local development based on geological and mining sites utilization, zaruma-portovelo, Ecuador

This study offers a detailed assessment of the geosites and mining sites present in the Zaruma-Portovelo mining district (Ecuador) through their qualitative and quantitative assessment. It shows up the potentiality of this area taking advantage of its geological-mining heritage. The methodological process includes: (i) compilation and inventory of all the sites within the study area with particular geological or mining interest; (ii) preparation of reports and thematic cartography, (iii) assessment and classification of the elements of geological-mining interest; (iv) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis and TOWS (Threats, Opportunities, Weaknesses, Strengths) matrix preparation seeking strategies to guarantee the viability of geotourism. A total of 16 sites of geological interest and 11 of mining interest were identified. The 77% of these sites was proved to be of high and very high interest in scientific terms. Likewise, their susceptibility to degradation assessed from their vulnerability and fragility was found to be high or very high in the 30% of the cases. As for the protection priority, all the studied sites obtained a medium-high result. Finally, the study based on the SWOT-TOWS revealed the possibility of applying action strategies in order to facilitate the compatibility of geotourism with the current productive activities, despite the difficult situation in the study area created by mining activities

Microscopic and NanoSIMS characterization of black shale-hosted pre-kinematic pyrites: Possible gold source of the orogenic gold deposits in the Truchas Syncline (Variscan Iberian Massif)

[EN] The Truchas Syncline contains orogenic gold deposits (OGDs), hosted mainly by the Armorican Quartzite Fm. In order to look for the source of gold in these deposits, pre-kinematic sulphides from black shales from the overlying Luarca Fm. were studied using both optical and scanning electron (SEM) microscopy, as well as nanoscale secondary ion mass spectrometry (NanoSIMS). NanoSIMS images allowed the observation of relevant structures (pyrite with high As content nodules) hidden to SEM. Microscopy and 36S, 75As32S, 75As, 75As34S, and 197Au mappings, as well as δ34S analysis (‰ Vienna-Canyon Diablo Troilite) allowed 4 types of pyrite to be characterized. According to their sequence of deposition, the pyrite types identified are the following: (1) framboid nuclei (FmPy), with δ34S between +4.1‰ and +57.5‰; (2) overgrowths (OgPy), with presence of Au, As and δ34S of approximately +20.5‰; (3) pyrite with high As content (AsPy), replacing previous pyrites, with δ34S of approximately +23‰, nodular shapes and non-detected Au; (4) subhedral pyrite (ShPy), with δ34S of approximately +19.7‰ and Au and As distribution showing (a) nuclei, (b) rims with Au and As and (c) structures interpreted as replacements of previous pyrite. Luarca Fm. pyrite framboids reach 75 μm in size, larger than framboids described in most previous NanoSIMS work, with microcrystals sufficiently large to be analyzed without contamination from edge effects. The FmPy formed in early diagenetic conditions by dissimilatory reduction of marine sulphate plus Rayleigh distillation or anaerobic oxidation of methane processes. The first FmPy nuclei formed in the periphery of framboids, and then started to form in the central region until completion of the framboidal structure. Growth of OgPy, AsPy and ShPy corresponded to more advanced diagenetic conditions, although the last stage of ShPy growth followed an aggregation model, in which ShPy metamorphic pyrites grew over ShPy diagenetic pyrites. The sulphur isotopic signature of the four types of pyrite is in good agreement with a source from Ordovician marine sulphate. A hypothesis stating that the source of Au in OGDs in the district could be in Luarca Fm. is supported by the results of the present research. Firstly, a source of Au in the district could have been the replacement of previous pyrites by AsPy and the release of Au to the system, instead of the framboidal to euhedral pyrite recrystallization process observed in other gold deposits. Secondly, by the correspondence between δ34S isotopic signature of the pyrites from Luarca Fm. and those from sulphides in OGDs. However, these results do not rule out other possible sources.SIThis project was funded by Project 0284_ESMIMET_3_E (INTERREG V-A Spain-Portugal Cooperation Programme, 2014-20) and by Project LE167G18 (Junta de Castilla y Le´on, Spain)

A GIS-supported Multidisciplinary Database for the Management of UNESCO Global Geoparks: the Courel Mountains Geopark (Spain)

[Abstract] The management of a UNESCO Global Geopark (UGGp) requires a vast wealth of miscellaneous scientific knowledge that can be successfully organised using a Geographical Information System (GIS). This paper presents a pragmatic GIS database to assist in the suitable governance of the Courel Mountains UGGp (2017) in Northwest Spain. The database is structured in 66 coverages compiled from public sources and previous works or produced through traditional mapping (combining fieldwork and photointerpretation) and GIS tools. The acquired data was later homogenised and validated by a multidisciplinary team and archived in independent coverages. Forty thematic maps illustrate the broad range of cartographic information included in the GIS database. Among them, 25 basic maps provide an overview of the UGGp and 15 new maps focus on crosscutting and technical issues. All maps illustrate the huge potential of GIS to create new resources combining coverages and adapting the legend according to their purpose and audience. The database facilitates the suitable publishing of consistent outputs (e.g., brochures, books, panels, webpages, web serves), as well as the elaboration of technical data to assist the park management. The database furnishes information on the design of education actions, touristic routes, activities and Geopark facilities. The GIS database is also a supportive tool for scientific research and provides the necessary knowledge to conduct geoconservation actions based on land use, geological hazards and the occurrence of natural and cultural heritages. Altogether, the GIS database constitutes a powerful instrument for policy-making, facilitating the identification and evaluation of alternative strategy plans.This work was developed in the framework of the Scientific Program of the Courel Mountains UGGp with the cooperation of tourism agents (A.M. Arza and A. López), roofing slate quarries (Pizarras de Villarbacú, Pizarras de Quiroga) and local people (M. Reinosa, G. Díaz, O. Álvarez). We are deeply grateful to J.R. Martínez Catalán (Universidad de Salamanca), A. Pérez-Alberti and J. Guitián (both from Universidade de Santiago de Compostela), J.R. Gutiérrez-Marco (ICOG, Universidad Complutense de Madrid/CSIC), J. Vegas (IGME-CSIC), L. González-Menéndez (IGME-CSIC), J.M. García Queijeiro (Universidade de Vigo), L. Santos and A. Grandal-D’Anglade (both from Universidade da Coruña) for their assistance supplying information involved in the database. We thank also E. de Boer for proofreading the article. DB is grant holder of Plan Andaluz de Investigación, Desarrollo e Innovación 2021, funded by Junta de Andalucí

Geology and metallogeny of the W-Sn and Au deposits in the Northwest of the Iberian Peninsula : Peña do Seo (West Astur Leonese Zone) and Trucas Syncline (Central Iberian Zone)

161 p.[ES] Esta Tesis Doctoral pretende contribuir al conocimiento de la geología regional del NW de Iberia, con especial énfasis en los yacimientos minerales variscos (W-Sn, Au), mediante un estudio detallado de la petrología, mineralogía, geoquímica de las rocas y procesos de formación de minerales que conducen a concentraciones económicas de metales. Se ha trabajado en dos áreas: Peña do Seo (Zona Asturoccidental Leonesa, WALZ) y El Sinclinal de Truchas (Zona Centroibérica, CIZ).[EN] This PhD Thesis aims at improving the knowledge of the regional geology in NW Iberia, with particular emphasis placed on Variscan mineral deposits (W-Sn, Au), through a detailed study of the petrology, mineralogy, geochemistry of the rocks and ore-forming processes leading to economic concentrations of metals. The work has been performed in two areas: Peña do Seo (West Asturian-Leonese Zone, WALZ) and The Truchas Syncline (Central Iberian Zone, CIZ).Unión Europea [0284_ESMIMET_3_E (INTERREG V-A Spain-Portugal Cooperation Programme, 2014-20)

Cómo distinguir minerales en base a sus propiedades

Serie: Semana de la Ciencia de Castilla y León 202

Tres casos de empresas internacionales con éxito: estudio de las estrategias de comunicación interna

Internal communication strategies have become a key element for business success of any company. This paper breaks down and analyzes the different internal communication policies of three major international companies and its structure. Channels of horizontal, transverse, descending and ascending communication employees in each of the corporations are defined, evaluating their effectiveness. Finally, this dissertation highlights the strengths of the strategies chosen in each case and are proposed as examples of good practice, and suggestions are made to improve management.As estratégias de comunicação interna têm sido convertidas em um elemento chave e indispensável para o êxito empresarial de qualquer companhia ou negócio. Este ensaio examina as diferentes políticas de comunicação interna de três grandes empresas internacionais e sua estrutura. Nesse sentido, serão descritos e definidos os canais e instrumentos de comunicação horizontal, transversal, descendente e ascendente empregados em cada uma das corporações, e avaliada sua efetividade. Finalmente, o trabalho sublinha as fortalezas das estratégias, escolhidas em cada caso, afim de propô-las como exemplos de boas práticas. Também são apresentadas sugestões para melhorar a gestão da comunicação interna em organizações.Las estrategias de comunicación interna se han convertido en un elemento indispensable y clave para erigir el éxito empresarial de cualquier compañía o negocio. Este ensayo desglosa y analiza las diferentes políticas de comunicación interna de tres grandes empresas internacionales y su estructura. Se definen los canales e instrumentos de comunicación horizontal, transversal, descendente y ascendente empleados en cada una de las corporaciones, evaluando su efectividad. Finalmente, esta disertación pone de relieve las fortalezas de las estrategias escogidas en cada caso y se proponen como ejemplos de buenas prácticas, al tiempo que se realizan sugerencias para mejorar su gestión

Tres casos de empresas internacionales con éxito: estudio de las estrategias de comunicación interna

As estratégias de comunicação interna têm sido convertidas em um elemento chave e indispensável para o êxito empresarial de qualquer companhia ou negócio. Este ensaio examina as diferentes políticas de comunicação interna de três grandes empresas internacionais e sua estrutura. Nesse sentido, serão descritos e definidos os canais e instrumentos de comunicação horizontal, transversal, descendente e ascendente empregados em cada uma das corporações, e avaliada sua efetividade. Finalmente, o trabalho sublinha as fortalezas das estratégias, escolhidas em cada caso, afim de propô-las como exemplos de boas práticas. Também são apresentadas sugestões para melhorar a gestão da comunicação interna em organizações.Internal communication strategies have become a key element for business success of any company. This paper breaks down and analyzes the different internal communication policies of three major international companies and its structure. Channels of horizontal, transverse, descending and ascending communication employees in each of the corporations are defined, evaluating their effectiveness. Finally, this dissertation highlights the strengths of the strategies chosen in each case and are proposed as examples of good practice, and suggestions are made to improve management.Las estrategias de comunicación interna se han convertido en un elemento indispensable y clave para erigir el éxito empresarial de cualquier compañía o negocio. Este ensayo desglosa y analiza las diferentes políticas de comunicación interna de tres grandes empresas internacionales y su estructura. Se definen los canales e instrumentos de comunicación horizontal, transversal, descendente y ascendente empleados en cada una de las corporaciones, evaluando su efectividad. Finalmente, esta disertación pone de relieve las fortalezas de las estrategias escogidas en cada caso y se proponen como ejemplos de buenas prácticas, al tiempo que se realizan sugerencias para mejorar su gestión

Geotourism and Local Development Based on Geological and Mining Sites Utilization, Zaruma-Portovelo, Ecuador

This study offers a detailed assessment of the geosites and mining sites present in the Zaruma-Portovelo mining district (Ecuador) through their qualitative and quantitative assessment. It shows up the potentiality of this area taking advantage of its geological-mining heritage. The methodological process includes: (i) compilation and inventory of all the sites within the study area with particular geological or mining interest; (ii) preparation of reports and thematic cartography, (iii) assessment and classification of the elements of geological-mining interest; (iv) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis and TOWS (Threats, Opportunities, Weaknesses, Strengths) matrix preparation seeking strategies to guarantee the viability of geotourism. A total of 16 sites of geological interest and 11 of mining interest were identified. The 77% of these sites was proved to be of high and very high interest in scientific terms. Likewise, their susceptibility to degradation assessed from their vulnerability and fragility was found to be high or very high in the 30% of the cases. As for the protection priority, all the studied sites obtained a medium-high result. Finally, the study based on the SWOT-TOWS revealed the possibility of applying action strategies in order to facilitate the compatibility of geotourism with the current productive activities, despite the difficult situation in the study area created by mining activities

The Peña do Seo W-Sn deposit, NW Iberia: Petrology, fluid inclusions and O-H-S isotopes

[EN] The Pe˜na do Seo W-Sn ore deposit in NW Iberia consists mainly of quartz veins hosted in schists. Vein mineralogy comprises wolframite, cassiterite and minor molybdenite. Peraluminous S-type granites and minor metaluminous granitoid breccias crop out in the same location. Whole rock geochemistry, mineral characterization, fluid inclusions and stable isotope geochemistry have been combined to infer hydrothermal mineralization conditions. A pre-ore stage (0) involving the alteration of host rocks, three stages of mineralization (I, II and III), and a supergene stage (IV) have been identified. Stage I (oxide-halide-sulfide stage) consisted of a cassiterite-pyritefluorite mineralization in granitoid breccias. Stage II (main oxide stage) involved wolframite-rich selvages and wolframite-cassiterite-(molybdenite) quartz veins. Stage III (main sulfide stage) consisted of a sulfide mineralization in quartz veins comprising pyrite and minor arsenopyrite and chalcopyrite. Three types of fluid inclusions were found in vein quartz: (1) aqueous two-phase inclusions, with homogenization temperatures (Th) between 445 ◦C and 280 ◦C and moderate salinities (9–14 wt% NaCl eq.), (2) aqueous-carbonic three-phase fluid inclusions, with Th from 340 ◦C to 260 ◦C and low salinities (2–7 wt% NaCl eq.), and (3) aqueous two-phase fluid inclusions, with Th from 270 ◦C to 155 ◦C and low salinities (0–6 wt% NaCl eq.). δ18O values in quartz from mineralized veins range from +11.2‰ to +13.4‰, and between +15.0‰ and +15.4% in quartz from mineralized granitoid breccias. δ34S values in sulfides (pyrite, arsenopyrite and chalcopyrite) range between +13.0 ‰ and +37.1 ‰, thus suggesting a marine source of sulfate and possible equilibration with host-rock sulfides. δD values in muscovite and chlorite from quartz veins range between 105.7 ‰ and 71.5 ‰ and between 69.4 ‰ and 67.1 ‰, respectively, indicating a transition from magmatic to magmatic-metamorphic conditions. An aqueous (H2O–NaCl) magmatic-hydrothermal fluid led to the W-Sn mineralization, as deduced from the studied fluid inclusions and isotopic signatures. High W and Sn contents in the peraluminous granites indicate that the W-Sn mineralization in Pe˜na do Seo could partially be related to the granites and granitoid breccias. Whereas the Sn (±W) likely derived from hydrothermal fluids exsolving from the crystallizing magmas, host quartz schists would have supplied other elements required for wolframite deposition such as Fe and Mn. Sulfide mineralization in stage III was probably driven by fluid dilution.This work was funded by Project 0284_ESMIMET_3_E (INTERREG VA Spain-Portugal Cooperation Programme, 2014-20) and by Project LE167G18 (Junta de Castilla y Le´on, Spain). Research of PC is funded by a PhD grant from the University of Le´on (Spain). The authors are grateful to Matthieu Harlaux, Editor Lisard Torr´o and an anonymous reviewer for their constructive comments, which significantly improved the quality of the manuscript. The excellent editorial handling by Editor-in- Chief Franco Pirajno is also greatly appreciated