Re-evaluation of the geothermal potential of the granites of Galicia based on geochemical and radiological cartography

[Resumen] el flujo de calor en la corteza superior determina la posibilidad de utilizar la energía geotérmica en una determinada zona. Este flujo es muy heterogéneo por lo que el aprovechamiento de la energía geotérmica es muy variable y requiere un estudio de cada zona. Donde no existen condicionantes geológicos que produzcan un flujo de calor anómalo y elevado, el aprovechamiento de esta energía es más limitado, dependiendo de las propiedades de las rocas del substrato, pero aun así enormemente variable. Los estudios realizados en Galicia hasta la fecha indican que el aprovechamiento geotérmico en esta comunidad es limitado debido a la ausencia de anomalías y a la litología, existiendo un potencial geotérmico bajo. Sin embargo, los principales estudios orientados a este fin, aun considerando información geológica, han sido genéricos, imprecisos y conservadores. La existencia de nuevos datos geoquímicos y de radiación gamma permite una reevaluación de estos estudios. Esta reevaluación muestra un potencial mayor del estimado inicialmente, lo que sugiere la necesidad de realizar estudios más detallados de la geoquímica de las rocas para obtener una evaluación más precisa y exacta, algo necesario para un desarrollo adecuado del aprovechamiento de esta energía en la comunidad[Abstract] The heat flux in the upper crust determines the availabili of geothermal energy resources whose use depending on the properties of the rocks substrate. In Galicia the geothermal exploitation is limited, because the low potential. However the existence of new geochemical and gamma radiation allows a re-evaluation carrying out more detailed studies of rock geochemistry to obtain a more precise evaluatón for an adequate development of the use of this energy

Geological materials as sources of Rn emissions

This is an author’s version (C. Alves) and not the final published text. The final published text can be found in Proceedings 2019, 24(1), 17; https://doi.org/10.3390/IECG2019-06193Geological materials are a potential source of pollutants, among which there is the radioactive isotope 222Rn, which result of radioactive decay of daughter radionuclides of uranium (238U). It is emitted as a gas that it can be released to the air to enter the human body, with the potential to affect internal organs (mostly the lungs) by alpha particles production. While the presence of uranium in the materials is a necessary condition for the production of Rn-222, the amount of gas emitted by the material depends on other characteristics that allow the migration of the gas. The main aim of this communication concerns a statistical analysis of results from diverse types of rocksThe Lab2PT—Landscapes, Heritage and Territory laboratory - AUR/04509 is supported by the Portuguese “Fundação para a Ciência e a Tecnologia” (Portuguese funds and where applicable the FEDER cofinancing, in the aim of the new partnership agreement PT2020 and COMPETE2020 - POCI 010145 FEDER 007528)

Electronic systems and offsite touristic activities based on geological concepts: a speculative discussion

The COVID-19 pandemic has caused havoc in many economic areas such as those related to tourism. This creates the need for alternative activities in this sector, especially given that it is not clear when the present emergency will end and there could be new situations of this kind. We consider here two main possibilities (virtual models and remote observations) for tourism related to geological objects (including those used by humans) and processes. These approaches could help to promote remote-operated tourism in other celestial bodies, helping to promote this kind of enterprise. These activities could be prepared with variable connection to education (for publics with diverse age ranges), prompting their use at any time of the year (hence minimizing the issue of seasonality). Our discussion suggests that remote observations will be the most interesting option since they could potentially give the users an unlimited diversity of experiences, it might give higher returns to local communities (but also higher loads on local environments) and they could find additional value in other geological applications. While our analysis is certainly very speculative at present, it can be submitted to falsification by the financial resultsThe Lab2PT‐Landscapes, Heritage and Territory laboratory ‐ UIDB/04509/2020 is supported by the Portuguese FCT ‐ “Fundação para a Ciência e a Tecnologia”. The authors also gratefully acknowledge the support of the CERENA (funded by a strategic project of the FCT-UIDB/04028/2020) and the LAMPIST of the DECivil, Instituto Superior Técnico, University of Lisbon, Portugal. The University Institute of Geology of the University of A Coruña (Spain) receives support from the Xunta de Galicia from the program “Consolidación y estructuración de unidades de investigación competitivas: Grupos de potencial de crecimiento” (ED431B 2018/47) and Redes de investigación (R2017/008)

Rock features and alteration of stone materials used for the built environment: a review of recent publications on ageing tests

This work presents a review of recent publications, with publication date between 2017 and 2019, with information on the relation between rock characteristics and the effects of diverse agents associated with alteration of stone materials in the built environment. It considers information obtained from ageing tests performed under laboratory conditions and by exposure to outdoor agents. Several lithological groups were considered, with sedimentary carbonate rocks being the most frequently studied lithotypes and silicate metamorphic rocks being the group with scarcer information. In terms of ageing tests, salt weathering was the most frequent one while there was a noticeable lesser amount of information from tests with biological colonization. The collected data showed the influence of diverse features, from specific minerals to whole-rock properties and the presence of heterogeneities. These information are discussed in the context of formulating a general framework for stone decay.The Lab2PT-Landscapes, Heritage and Territory laboratory-AUR/04509 is supported by the Portuguese FCT-“Fundação para a Ciência e a Tecnologia” (Portuguese funds and where applicable the FEDER co-financing, in the aim of the new partnership agreement PT2020 and COMPETE2020-POCI 010145 FEDER 007528). The authors also gratefully acknowledge the support of the CERENA (funded by a strategic project of the FCT-UID/ECI/04028/2019) and the LAMPIST of the Instituto Superior Técnico, University of Lisbon. The University Institute of Geology of the University of A Coruña (Spain) receives support from the Xunta de Galicia from the programme “Consolidación y estructuración de unidades de investigación competitivas: Grupos de potencial de crecimiento” (ED431B 2018/47) and Redes de investigación (R2017/008)

Assessment by portable gamma spectrometry of external gamma radiation hazard due to granitic materials and indoor space typology

Building materials can contribute to ionizing radiation hazards due to their variable content in radioactive isotopes. Uranium, thorium, and potassium radioisotopes are present in various building materials due to their presence in raw materials: minerals and rocks. Among natural building materials, granite is one of those deserving more attention in terms of radioactive hazards. Granites are commonly used in historical buildings of NW Portugal and NW Spain, due to the geological characteristics of these areas. However, radioactive isotopes are present in variable proportions in granites, and thus, in relation to other potential building materials, granites might present a higher radiological hazard. This work discusses multivariate analysis results obtained by spectrometry of a portable range in indoor spaces, presenting different proportions of granite used as a building material in order to evaluate a typology proposed for assessing gamma radiation hazards.The Lab2PT—Landscapes, Heritage and Territory laboratory—AUR/04509 is supported by the Portuguese “Fundação para a Ciência e a Tecnologia” (Portuguese funds and where applicable the FEDER co-financing, in the aim of the new partnership agreement PT2020 and COMPETE2020—POCI 01 0145 FEDER 007528). The University Institute of Geology of the University of A Coruña (Spain) received support from Xunta de Galicia with funds from “Consolidación y estructuración de unidades de investigación competitivas—Grupo de potencial de crecimiento” (GPC2015/024) and “Redes de Investigación (ED431D 2017/08). We also would like to thank Mara Dória and Tomaz Assunção for their collaboration in the field work.info:eu-repo/semantics/publishedVersio

An Interdisciplinary Study of Early Mediaeval Churches in North-Western Spain (Galicia)

[Abstract:] Over the last five years, the EMCHAHE (Early Medieval Churches: History, Archaeology and Heritage) Project has analysed the architecture, archaeology and history of numerous rural churches of the High Middle Ages in Galicia (NW Spain), through its historical, stratigraphic and chronological study. As a result, the knowledge of this historical period has been broadened and even changed, as well as an interdisciplinary methodology on how to approach this type of study. According to the results obtained, the project has allowed us to reflect on two issues, the potential of a relatively low-cost type of study to understand, assess and disseminate this type of heritage and the special appreciation and ownership that local communities have towards these churches as an engine of sustainable social development

Covering layers on granite buildings of northwestern Iberian Peninsula: when observable characteristics and lab characterization do not match

[Abstract] Illustrated glossaries on stone pathologies help to describe deterioration forms in built heritage without resorting to any laboratory analyses. In this way, terms such as crust, deposit, and soiling which according to ICOMOS-ISCS: Illustrated Glossary on Stone Deterioration Patterns may include exogenic material, a patina which results from ageing of the material in an endogenous process, and a film included under the broad term of a coating layer in the glossary, can be macroscopically identified on site. However, a definition on the basis of characteristics only observable with the naked eye (without further analysis in the laboratory) is certainly complicated, and if in addition, the case studies are on granitic rock (a major building stone used across Europe), the picture becomes even more complicated. The intention of this brief report is to engender an open, constructive debate about the casuistry of the covering layers on granite (a poorly reactive and less porous rock) and the difficulty of using the ICOMOS nomenclature on them.Xunta de Galicia; ED431C 2018/32Xunta de Galicia; GPC2015/02

An overview of radiological hazards related to geological external Gamma radiation in outdoor environments

Rocks and soils are an important source of external gamma radiation due to their content in U, Th, and K. The dose rate derived from the emission of gamma-rays of radioisotopes can be directly measured or assessed from their content. In the present study, values of outdoor gamma radiation absorbed dose rate are analyzed to explore the implications of levels related to those values in terms of the exposure time necessary for attaining a certain yearly effective dose. We propose simple relations with the absorbed dose rate and with the gamma index of materials.The Lab2PT- Landscapes, Heritage and Territory laboratory - AUR/04509 is supported by the Portuguese “Fundação para a Ciência e a Tecnologia” (Portuguese funds and where applicable the FEDER co-financing in the aim of the new partnership agreement PT2020 and COMPETE2020 - POCI 01 0145 FEDER 007528). The University Institute of Geology of the University of A Coruña (Spain) received support from Xunta de Galicia with funds from “Consolidación y estructuración de unidades de investigación competitivas - Grupo de potencial de crecimiento” (GPC2015/024).info:eu-repo/semantics/publishedVersio

Evaluación de la meteorización de rocas graníticas en edificios históricos urbanos por medio de indices geoquímicos

Weathering involves important processes that alter the original structure, texture and chemical components of rocks and minerals. Bulk changes produced by weathering in granitic rocks have been studied by several methods, including chemical weathering indices. They are based on the assumption that some ions are more easily leached from minerals in relation to others. Such methods have also been briefly tested on building stone but not in urban environments, where fast stone weathering rates are typically observed, mainly due to interaction of minerals with several pollutants and where other specific processes, such as salt weathering, can occur. The aim of this work is to discuss the use of weathering indices in the study of weathering rates on granitic stones applied in four historical buildings of an urban area. Results suggest that some factors can cause scatter of results in the relation indices vs. exposition age in the built environment, namely previous weathering degree in rock massifs and the quarry, different orientation of façades and different exposure to urban pollutants. Indices that consider some highly mobile cations that are present in other building materials (namely Ca that is related to leaching from mortar joints) should be avoided due to the uptake of such elements by the stone pores or used to assess this some types of weathering. Moreover, the use of some indices shows more reliable results.La meteorización implica importantes procesos que alteran la estructura, textura y componentes quimicos originales de las rocas y minerales. Los cambios producidos por la meteorización en rocas graniticas han sido estudiados por varios métodos, incluyendo los índices de meteorización química. Éstos se basan en la suposición de que algunos iones son lavados de los minerales más fácilmente que otros. Tales métodos también se han probado, aunque en pocos casos, en rocas de edificios, pero no de ambientes urbanos, en donde se han observado tipicamente elevadas tasas de meteorización, principalmente por la interacción de los minerales con varios compuestos contaminantes y en dónde otros procesos específicos, tales como la erosión por sales, pueden producirse. El objetivo de este trabajo es discutir el uso de indices de meteorización en el estudio de las tasas de meteorización de rocas usadas en cuatro edificios históricos de un área urbana. Los resultados sugieren que algunos factores pueden causar la dispersión de los resultados obtenidos a través de los indices en relación al tiempo de exposición en el ambiente construido, principalmente por el grado de meteorización previo de la roca en los macizos rocosos y en la cantera, la orientación de las fachadas y la diferente exposición a compuestos contaminantes. Los índices que consideran algunos cationes altamente móviles que están presentes en otros materiales de construcción (principalmente el Ca que se relaciona con la meteorización de morteros en las juntas) deben ser evitados debido a que penetran en los poros de las rocas de edificios o deben ser usados para evaluar algunos tipos de meteorización. Por otra parte, el uso de algunos índices muestra resultados más fiables.Este trabalho insere-se nas atividades do Projeto Lab2PT- Laboratório de Paisagens, Património e Território - AUR/04509 que tem o apoio financeiro da FCT/MCTES através de fundos nacionais (PIDDAC) e o cofinanciamento do Fundo Europeu de Desenvolvimento Regional (FEDER), refª POCI-01-0145-FEDER-007528, no âmbito do novo acordo de parceria PT2020 através do COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI).info:eu-repo/semantics/publishedVersio

Remote operations could be the future for Earth Sciences teaching: a speculative discussion

[Abstract] The current COVID-19 pandemic has created havoc in the regular workings of many institutions, such as those dedicated to teaching; therefore, there is an urge for alternatives to traditional face-to-face teaching. However, for certain subjects, such as Earth Sciences, distance-teaching approaches could be seen as counterintuitive to the essential foundations of the subject (where empirical information, especially from fieldwork, is considered paramount for its foundation and growth). In this work, we consider remote operations that could complement, improve, and perhaps even replace the traditional approach for teaching Earth Sciences, potentially producing better learning outcomes, even in relation to laboratory and fieldwork, including studies involving locations outside of planet Earth. Additionally, we consider the possible advantages for other professional settings related to this area, such as those concerning terrain characterization for engineering works, mineral resources, and environmental studies, as well as possible support for space missions and stations in other astronomical bodies (where mineral exploration and extraction could be developed and, hence, benefit from remote operations).Portugal. Fundação para a Ciência e a Tecnologia; FCT-UIDB/04509/2020Portugal. Fundação para a Ciência e a Tecnologia; FCT-UIDB/04028/2020Xunta de Galicia; ED431B 2018/47Xunta de Galicia; R2017/00