Density and magnetic susceptibility relationships in non-magnetic granites; a “wildcard” for modeling potential fields geophysical data

EGU2020: Sharing Geoscience Online, 4-8 May 2020Geophysical surveying (both gravity and magnetic) is of great help in 3D modeling of granitic bodies at depth. As in any potential-field geophysics study, petrophysical data (density [r], magnetic susceptibility [k] and remanence) are of key importance to reduce the uncertainty during the modeling of rock volumes. Several works have already demonstrated that ¿18O or [SiO2] display a negative correlation to density and to magnetic susceptibility. These relationships are particularly stable (and linear) in the so-called ¿non-magnetic¿ granites (susceptibilities falling within the paramagnetic range; between 0 and 500 10-6 S.I.) and usually coincident with calc-alcaline (CA) compositions (very common in Variscan domains). In this work we establish robust correlations between density and magnetic susceptibility at different scales in CA granites from the Pyrenees. Other plutons from Iberia were also considered (Veiga, Monesterio). The main goal is to use the available and densely sampled nets of anisotropy of magnetic susceptibility (AMS) data, performed during the 90¿s and early 2000¿s, together with new data acquired in the last few years, as an indirect measurement of density in order to carry out the 3D modelling of the gravimetric signal. We sampled some sections covering the main range of variability of magnetic susceptibility in the Mont Louis-Andorra, Maladeta and Marimanha granite bodies (Pyrenees), all three characterized by even and dense nets of AMS sites (more than 550 sites and 2500 AMS measurements). We performed new density and susceptibility measurements along two main cross-sections (Maladeta and Mont Louis-Andorra). In these outcrops, numerous measurements (usually more than 50) were taken in the field with portable susceptometers (SM20 and KT20 devices). Density data were derived from the Arquimedes principle applied on large hand samples cut in regular cubes weighting between 0.3 and 0.6 kg (whenever possible). These samples were subsampled and measured later on with a KLY-3 susceptibility bridge in the laboratory. Additionally, some density data were derived from the geometry and weighting of AMS samples. After the calibration of portable and laboratory susceptometers, density and magnetic susceptibility were plotted together. Regressions were derived for every granite body and they usually followed a linear function similar to: r = 2600 kg/m3 + (0.5 * k [10-6 S.I.]). As previously stated, this relationship is only valid in CA and paramagnetic granites, where iron is mostly fractioned in iron-bearing phyllosilicates and the occurrence of magnetite is negligible (or at least its contribution to the bulk susceptibility). These relationships allow transforming magnetic susceptibility data into density data helping in the 3D modelling of the gravimetric signal when density data from rock samples are scarce. Given the large amount of AMS studies worldwide, together with the quickness and cost-effectiveness of susceptibility measurements with portable devices, this methodology allows densifying and homogenizing the petrophysical data when modelling granite rock volumes based on both magnetic and gravimetric signal

Basement and cover architecture in the Central Pyrenees constrained by gravity data

A new gravity survey (1164 gravity stations and 180 samples for density analysis) combined with two new geological cross sections has been carried out in a sector of the Central Pyrenees in order to improve the characterization of basement and cover architecture. From North to South, the study area comprises the southern half of the Axial Zone and the northernmost part of the South-Pyrenean Zone. New gravity data were combined with previous existing databases to obtain the Bouguer and residual anomaly maps of the study area. The two cross sections, oriented NNE–SSW, were built from field data and previous surficial and subsurface data and cross the La Maladeta plutonic complex. The residual anomaly map shows values ranging from −18 to 16 mGal and anomalies mainly oriented N120E. The two 2.5D modelled cross sections show similar observed gravity curves coinciding with similar interpreted structural architecture. Data show a gravity high oriented N120E coinciding with the Orri basement thrust sheet and an important gravity depression, with the same orientation, coinciding with the leading edge at depth of the Rialp basement thrust sheet and interpreted as linked to a large subsurface accumulation of Triassic evaporites. The volume at depth of the La Maladeta and Arties granites has been constrained through gravity modelling. This work highlights that the combination of structural geology and gravity modelling can help to determine the structural architecture of an orogen and localize accumulations of evaporites at depth.This work is part of the project CGL2017-84901-C2-2-P funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe” and project PID2020-114273GB-C22 funded by MCIN/AEI/10.13039/501100011033 from Spanish Ministry of Science, Innovation and Universities. Seequent has provided us the GM-SYS module of the Oasis Montaj. The authors acknowledge the contribution of José María Llorente and Agustin González for the acquisition of the gravity data. We thank to Aigüestortes National park and Alt Pirineu Natural park their logistic support. We thank anonymous reviewer for improving the content in the manuscript. This study represents a contribution to GeoAp Research Group (E01-20R) (Aragón Government).Peer reviewe

Charla video "Una historia ilustrada de minerales accesorio y procesos ígneos: El Circón." Geoloquios Virtuales. Centro de Estudiantes de Geología (CEG UCN), Universidad Católica del Norte (Chile)

Geoloquios Virtuales. Centro de Estudiantes de Geología (CEG UCN), Universidad Católica del Norte (Chile): Décimo Geoloquio Virtual del mes de julio. Una historia ilustrada de minerales accesorio y procesos ígneos: El Circón. Por Nia Schamuells, Geóloga, Doctorante de la Universidad de Barcelona. CSIC Geosciences Barcelona

Charla via Youtube "Mineralizaciones Vinculadas a Procesos Magmáticos-Hidrotermales en los Pirineos Catalanes. (España) para el SEG Student Chapter UNSA-Arequipa (IV ciclo de conferencias)

IV Ciclo de Conferencias Student Chapter UNAS-AREQUIPA (Perú) Mineralizaciones Vinculadas a Procesos Magmáticos-Hidrotermales en los Pirineos Catalanes por Nia Schamuells. Charla para el SEG Student Chapter UNSA-Arequipa (IV ciclo de conferencias

Charla via youtube "Tips para libretas de campo: cómo dibujar columnas y cortes geológicos"

Charla a cargo de Nia Schamuells @salirconunageologa. ESA: Encuentro de Sociabilidad Académica. Universidad de Río Negro (Universidad Nacional- Argentina

Charla video "Razones para dibujar la Geología" por Stefania (Nia) Schamuells Para «Ciència en confinament»: 18n. Organizador: Joan Antón Català

Charla video "Razones para dibujar la Geología" por Stefania (Nia) Schamuells Para «Ciència en confinament»: 18n

Morphometric analysis of the post-caldera monogenetic volcanoes at Deception Island, Antarctica: implications for landform recognition and volcanic hazard assessment

EGU2020: Sharing Geoscience Online, 4-8 May 2020Deception Island is one of the most active volcanoes in Antarctica, with more than 20 monogenetic eruptions during the Holocene. The latest episodes of 1967, 1969 and 1970 have shown that volcanic activity on Deception Island can become a concern for tourists, scientists, and military personnel working on or near the island. The objective of this work is, therefore to identify eruptive processes and the evolution of post-caldera volcanic edifices at Deception Island by morphometric analysis, supported by field observations. This methodology has been used since the 1970s to analyse mafic monogenetic volcanoes but it has not been fully developed until recently. Tuff cones and rings, as a result of magma-water interaction, represent the most common eruptive events occurring during Deception Island's recent geological past and are therefore the most likely to occur in the near future. This work provides an opportunity to incorporate for the first time at Deception Island geomorphological observations for a better comprehension of the potential evolution of a future eruption and for a broader understanding of volcanic hazards on this island.This research was supported by the MICINN grant CTM2011- 13578-E and was partially funded by the POSVOLDEC project (CTM2016-79617-P) (AEI/FEDER-UE). A.G. is grateful for her Ramón y Cajal contract (RYC-2012-11024). D.P. is grateful for his Beatriu de Pinós (2016 BP 00086) and Juan de la Cierva (IJCI-2016-30482) contracts. This research is part of POLARCSIC and AntVolc activitie

Earth Scientist and Social Media: approaching our planet to young people and general public using comics and illustration.

vEGU21: Gather Online | 19-30 April 2021Earth Sciences are booming in social media, an unexampled scenario a few years ago. In the last year, these numbers have increased because of the COVID-19, citizens are consuming even more digital information, at the same time they are looking for more simplified and easy-understanding scientific concepts. It is very important to remark the value of entertainment, humor, and visual contents, which have a light universal language to approach Earth Sciences to citizens and experts beyond the pure academic frontiers. In this work, we share some successful examples through the use of illustration, comic, and infographic content between two Instagram accounts (@ohmagmamia and @salirconunageologa) which addend more than 13,000 followers and have a potential reach up to 37.1k (based on their account insights). The audience for this content is international although it has gained great popularity among the Spanish-speaking public (the initial target audience), little by little creating an interesting and growing movement. Countries such as Chile, Argentina, Colombia, and Spain have the greatest impact according to statistics. Age range is between 18-34 years for 87% of the audience, with a clearly female predominance (55% in @Ohmagmamia and 60% in @Salirconunageologa). One of the principal goals of these accounts is to develop visual, artistic and easy-understanding content that fits the audience. On one hand @Ohmagmamia uses photographic material (e.g. landscapes, outcrops, hand specimen samples or micro-photographies), simple geological sketches and infographic content along with small descriptions in the post captions. This approach has been well received by both Earth Science students and non-professional enthusiasts, as well as biology-geology teachers and public examination trainers. On the other hand, @Salirconunageologa (Dating a geologist) uses cartoons, humour and comics to approach Earth Sciences to professionals and the general public. Its visual material focuses on storytelling to explain what it means to be a geologist using all its universe of friendly characters. In the first season of ¿Dating a Geologist Universe¿ (with 17 episodes), the main character, Nia Stone, is involved in different hilarious situations related to Earth Sciences, like volcanoes, trilobites, or Dr. Gems (the main Villain). This ¿geocomics¿ have been very well received, being the first chapter the one which records the best audience data, with 10k accounts reached on Instagram. Social media statistics data provide interesting information about the success of these scientific dissemination¿s new methods. In the last 6 months of the 2020 both accounts reached an average of 11,000 Instagram accounts with an average more than 1,000 ¿likes¿ per post and with an engagement rate that varies from 9 to 12%. In addition, the use of other social media such as Twitter or YouTube able us to reach more people and/or accounts by using Twitter ¿threads¿ or sharing videos of invite talks or ¿webinars¿, whose popularity grew during the quarantine period. All these results show the importance of a perfect relation between visuals, art and Earth Science and its capability to reach people from all around the globe

Talleres : >La baralla del temps geològic> , >Taller de vulcanologia>, >Falles i terratrèmols>

Talleres : >La baralla del temps geològic> de Armand Hernández, >Taller de vulcanologia>de Darío Pedrazzi y Stefania Schamuells, >Falles i terratrèmols>de Irene Pérez y Irene de Felipe a EXPOMINER 201

GEODA: Geological Society of Spain Outreach Commission

X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - GasteizUna de las tareas más relevantes de la ciencia es transmitir sus conocimientos más allá de lo estrictamente científico. La divulgación en Ciencias de la Tierra sigue siendo una tarea en desarrollo, una disciplina que en los últimos años ha ido ganando relevancia con la figura de las/os divulgadoras/es científicas/os. La Comisión de Divulgación de la Sociedad Geológica de España -GEODA- nace como respuesta a este movimiento en auge. Dentro de los objetivos de la Comisión se establece crear y compartir contenido único y original, con un lenguaje ameno, cercano e inclusivo, así como favorecer el intercambio de experiencias entre divulgadoras/es. Además pretende promover la divulgación geológica responsable y establecer mecanismos de difusión en todos los formatos disponibles que contribuyan a la información, formación, participación y sensibilización en la divulgación geológica y disciplinas afines. Se impulsará la creación y consolidación de un repositorio propio y base de datos web con las páginas de divulgación en Ciencias de la Tierra. A su vez se evaluará el desarrollo de acciones y estrategias de divulgación para crear vías de conexión con las administraciones públicas y demás instituciones sociales, científicas y medios de comunicación. Para todos estos fines se organizarán diversas actividades, como congresos y encuentros, charlas presenciales o virtuales, salidas de campo, actividades abiertas al público y encuentros de divulgadores. El contenido creado y compartido se publicará periódicamente en la web de GEODA y sus redes sociales (Instagram, Twitter y Facebook). Se realizarán reuniones de carácter divulgativo, publicaciones, investigaciones, estudios y artículos de interés general y cualquier otro medio que lleve a un mayor acercamiento y cooperación entre sus colaboradores y público, así como con grupos y asociaciones de características similares.One of the most important tasks of science is to transmit its knowledge beyond the scientific community. Earth Sciences outreach is still a work in progress, a discipline that in recent years has been gaining relevance with the figure of science communicators. The GEODA Outreach Commission of the Geological Society of Spain was born in response to this movement. One of the goals of the Commission is to create and share unique and original content, with a pleasant, friendly and inclusive language, and to promote the interchange of experiences between disseminators. In addition, to promote responsible geological outreach and to establish dissemination mechanisms in all formats that contribute to information, training, participation and awareness-raising in geological outreach and related disciplines. The consolidation and creation of a repository and web database of Earth Sciences outreach pages will be promoted. The development of dissemination actions and strategies will be evaluated in order to create and develop channels of connection with public administrations, social and scientific institutions and the media. For all these purposes, various activities will be organised: congresses and meetings, face-to-face or virtual talks, field trips, activities open to the public and meetings of disseminators. Contents created will be published periodically on the GEODA website and its social media (Instagram, Twitter and Facebook). The Commission will carry out informative meetings, research, scientific publications, studies and articles of general interest, and any other methods to strengthen the cooperation between GEODA’s collaborators and the public or other groups/associations with similar characteristics