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.
In this work we establish reliable correlations between density and magnetic susceptibility in three paramagnetic granites from the Pyrenees. In total, 128 sites (310 density measurements and >2600 susceptibility ones) were studied in the Mont Louis-Andorra, Maladeta and Marimanha granitic plutons covering the main range of variability of magnetic susceptibility. Regressions were calculated for every granitic body and an integrated linear function was obtained for the entire dataset: ρ (kg/m3) = 2566 (kg/m3) + 0.541κ (10−6 S.I.) (R:0.97). This relationship is only valid in the paramagnetic domain, 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). This relationship, likely different in other bodies, allows for transforming magnetic susceptibility data into density data, helping to constrain gravity modelling 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 for densifying and homogenizing the petrophysical data when modelling granite rock volumes based on both magnetic and gravimetric signals.
<p>Earth 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 (<strong>@ohmagmamia</strong> and <strong>@salirconunageologa</strong>) 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).</p><p>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 &#8220;Dating a Geologist Universe&#8221; (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 &#8220;<strong>geocomics&#8221;</strong> have been very well received, being the first chapter the one which records the best audience data, with 10k accounts reached on Instagram.&#160;</p><p>Social media statistics data provide interesting information about the success of these scientific dissemination&#8217;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 &#8220;likes&#8221; 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 &#8220;threads&#8221; or sharing videos of invite talks or &#8220;webinars&#8221;, 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.</p>
<p>In the Central Pyrenees, where density contrast between the Paleozoic rocks and the intruded granitic bodies is measurable, geological cross-sections constrained with gravity data help to unravel the subsurface geometry of the granites.</p><p>With this goal in mind, during 2018 and 2019 several gravimetric surveys were carried out in the Central Pyrenees to improve the existent spatial resolution of the gravity data from the databases of the Spanish and Catalan Geological Surveys, especially in La Maladeta and Andorra Mont-Louis granites&#8217; area. After the gravity reductions, we obtained the Bouguer gravity anomaly from which we calculated the residual gravity anomaly by subtracting a third degree polynomial which represents the regional anomaly in agreement with the geometry of the crust in this region.</p><p>The gravimetric response over La Maladeta and Andorra Mont-Louis granites is markedly dissimilar pointing out differences in the composition and geometry at depth of the two granites. La Maladeta granite shows a gravimetric zonation with small variations in its amplitude from one zone to the next, consistent with small lateral changes in its composition, predominantly granodioritic. By contrast, the Andorra Mont-Louis pluton is characterized by a relative minimum suggesting a more granitic composition.</p><p>With respect to the inferred geometry at depth, the results obtained from gravity modelling show that the La Maladeta granite displays a laccolithic shape with its basal contact deeping to the North whereas the Andorra Mont-Louis granite has a more batholitic shape. Although the emplacement age of both granites is similar (Late Carboniferous &#8211; Early Permian), their different geometry at depth suggests that either (1) their emplacement mechanisms were different or (2) the subsequent Alpine orogeny affected both granites in different ways better preserving the original geometry of the Andorra Mont-Louis granite.</p>
Integrated, Coordinated, Open, Networked (ICON) science aims to enhance synthesis, increase resource efficiency, and create transferable knowledge (Goldman et al., 2021). This article belongs to a collection of commentaries spanning geoscience on the state and future of ICON science. Global Collaboration, Reproducibility, Data Sharing and InfrastructureFair access to meaningful and well-documented data is the foundation of implementing ICON-FAIR (FAIR = Findable, Accessible, Interoperable, Reusable, Wilkinson et al., 2016) principles in GPE science. Data sharing comprises the "C" for the necessary coordinated effort, "O" for openly available data and processing tools and "N" for the networked effort to contribute data to a wider community for mutual benefit. It further allows for integration across disciplines ("I"), for example, between geophysics and space physics. Here we compare data sharing practices in GPE subdisciplines, identify causes of the status quo, and pathways toward equitable data access. These may also apply to model and software sharing.The three GPE communities include Geomagnetism (studying Earth's recent magnetic field variations), Paleomagnetism (studying the Earth's past field recorded in rocks) and Electromagnetism (EM) (imaging the subsurface with electromagnetic field variations). Geomagnetism has a long data sharing tradition and established
Integrated, Coordinated, Open, Networked (ICON) science aims to enhance synthesis, increase resource efficiency, and create transferable knowledge (Goldman et al., 2021). This article belongs to a collection of commentaries spanning geoscience on the state and future of ICON science. Global Collaboration, Reproducibility, Data Sharing and InfrastructureFair access to meaningful and well-documented data is the foundation of implementing ICON-FAIR (FAIR = Findable, Accessible, Interoperable, Reusable, Wilkinson et al., 2016) principles in GPE science. Data sharing comprises the "C" for the necessary coordinated effort, "O" for openly available data and processing tools and "N" for the networked effort to contribute data to a wider community for mutual benefit. It further allows for integration across disciplines ("I"), for example, between geophysics and space physics. Here we compare data sharing practices in GPE subdisciplines, identify causes of the status quo, and pathways toward equitable data access. These may also apply to model and software sharing.The three GPE communities include Geomagnetism (studying Earth's recent magnetic field variations), Paleomagnetism (studying the Earth's past field recorded in rocks) and Electromagnetism (EM) (imaging the subsurface with electromagnetic field variations). Geomagnetism has a long data sharing tradition and established
<p>Geophysical 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 &#8706;<sup>18</sup>O or [SiO<sub>2</sub>] display a negative correlation to density and to magnetic susceptibility. These relationships are particularly stable (and linear) in the so-called &#8220;non-magnetic&#8221; granites (susceptibilities falling within the paramagnetic range; between 0 and 500 10<sup>-6</sup> 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&#8217;s and early 2000&#8217;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.</p><p>&#160;</p><p>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.</p><p>&#160;</p><p>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/m<sup>3</sup> + (0.5 * k [10<sup>-6</sup> 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.</p>
<p>Deception 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.</p><p>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.</p><p>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.</p><p>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 Ram&#243;n y Cajal contract (RYC-2012-11024). D.P. is grateful for his Beatriu de Pin&#243;s (2016 BP 00086) and Juan de la Cierva (IJCI-2016-30482) contracts. This research is part of POLARCSIC and AntVolc&#160;activities</p>
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