De Salamanca a la Antártida: clase de vulcanología desde la base antártica española Gabriel de Castilla (volcán de Isla Decepción)

Memoria ID-0035. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2017-2018

Noble gas variation during partial crustal melting and magma ascent processes

Noble gas isotopes, although present in trace amounts, are generally more reliable and less ambiguous recorders of their source than the major volatile species. In volcanic settings in particular, this advantage derives from their chemical inertness, as noble gas isotopic and elemental fractionations are strongly coupled to their source and modified only by physical processes during magma ascent and eruption. The Neogene volcano El Hoyazo (Betic Cordillera, SE Spain) is a highly favourable natural laboratory to study the links between partial crustal melting processes occurring at depth and the eruptive products at the surface, because partially melted crustal xenoliths are preserved in silicic lavas. Comparing the noble gas isotopic compositions of xenoliths and lavas has the potential to yield new insights into volatile behaviour during melting processes at inaccessible depths in the crust. At El Hoyazo, noble gases trapped in lava glasses, and the fluid/melt inclusions within xeno- and phenocrysts, provide novel information on: (i) their response to the crustal melting process including mechanisms such as magma mixing (and crustal assimilation) of two endmembers: i.e. the extracted felsic melt from the country metapelitic crust, and the basic-intermediate magma from the underplating in the region. The results reveal significant modification of magmatic noble gases by the interaction with the partially melted crust; (ii) noble gas variations during degassing and magma ascent, showing higher atmospheric influence in the lava samples from shallower depths than in the deeper lavas and minerals; and (iii) higher magmatic influence in crystals of garnet from deeper lava than in both shallower crystals of amphibole, and garnet crystals within the crustal xenoliths. In addition, we find that noble gases in melt inclusions are also likely accumulating in their shrinkage bubbles, and not only remaining dissolved in the melt.Postprint3,51

Introducción a la investigación científica en geoquímica aplicada

Memoria ID12-0030. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2012-2013

Author Correction: Noble gas isotopes reveal degassing-derived eruptions at Deception Island (Antarctica): implications for the current high levels of volcanic activity

Peer reviewe

Integration of Methodologies for the Evaluation of Offer Curves in Energy and Capacity Markets through Energy Efficiency and demand Response

[EN] The objectives of improving the efficiency, and integration, of renewable sources by 2030-2050 are complex in practice and should be linked to an increase of demand-side flexibility. The main challenges to achieving this flexibility are the lack of incentives and an adequate framework. For instance, customers' revenue is usually low, the volatility of prices is high and there is not any practical feedback to customers from smart meters. The possibility of increasing customer revenue could reduce the uncertainty with respect to economic concerns, improving investments in efficiency, enabling technology and thus, engaging more customers in these policies. This objective could be achieved by the participation of customers in several markets. Moreover, Demand Response and Energy Efficiency can share ICT technologies but this participation needs to perform an aggregation of demand. The idea of this paper is to present some methodologies for facilitating the definition and evaluation of energy versus cost curves; and subsequently to estimate potential revenues due to Demand Response. This can be accomplished by models that estimate: demand and energy aggregation; economic opportunities and benefits; impacts on customer convenience; customer feedback and price analysis. By doing so, we would have comprehensive information that can help customers and aggregators to define energy packages and their monetary value with the objective of fostering their market participation.This work was supported by the Ministerio de Economia, Industria y Competitividad (Spanish Government) under research projects ENE2015-70032-REDT, ENE-2016-78509-C3-1-P&2-P and EU FEDER funds. Authors have also received funds from these grants for covering the costs to publish in open access.Gabaldón, A.; Álvarez, C.; Ruiz-Abellón, M.; Guillamón, A.; Valero-Verdú, S.; Molina, R.; Garcia-Garre, A. (2018). Integration of Methodologies for the Evaluation of Offer Curves in Energy and Capacity Markets through Energy Efficiency and demand Response. Sustainability. 10(2):1-27. https://doi.org/10.3390/su10020483S12710

The timing and widespread effects of the largest Holocene volcanic eruption in Antarctica.

The caldera collapse of Deception Island Volcano, Antarctica, was comparable in scale to some of the largest eruptions on Earth over the last several millennia. Despite its magnitude and potential for far-reaching environmental effects, the age of this event has never been established, with estimates ranging from the late Pleistocene to 3370 years before present. Here we analyse nearby lake sediments in which we identify a singular event produced by Deception Island's caldera collapse that occurred 3980 ± 125 calibrated years before present. The erupted tephra record the distinct geochemical composition of ejecta from the caldera-forming eruption, whilst an extreme seismic episode is recorded by lake sediments immediately overlying the collapse tephra. The newly constrained caldera collapse is now the largest volcanic eruption confirmed in Antarctica during the Holocene. An examination of palaeorecords reveals evidence in marine and lacustrine sediments for contemporaneous seismicity around the Antarctic Peninsula; synchronous glaciochemical volcanic signatures also record the eruption in ice cores spread around Antarctica, reaching >4600 km from source. The widespread footprint suggests that this eruption would have had significant climatic and ecological effects across a vast area of the south polar region

Noble gas isotopes reveal degassing-derived eruptions at Deception Island (Antarctica): implications for the current high levels of volcanic activity

Deception Island is one of the most active volcanoes in Antarctica with more than twenty explosive eruptions in the past two centuries. Any future volcanic eruption(s) is a serious concern for scientists and tourists, will be detrimental to marine ecosystems and could have an impact to global oceanographic processes. Currently, it is not possible to carry-out low and high frequency volcanic gas monitoring at Deception Island because of the arduous climatic conditions and its remote location. Helium, neon and argon isotopes measured in olivine samples of the main eruptive events (pre-, syn- and post caldera) offer insights into the processes governing its volcanic history. Our results show that: (i) ascending primitive magmas outgassed volatiles with a MORB-like helium isotopic signature (3He/4He ratio); and (ii) variations in the He isotope ratio, as well as intensive degassing evidenced by fractionated 4He/40Ar* values, occurred before the beginning of the main eruptive episodes. Our results show how the pre-eruptive noble gas signals of volcanic activity is an important step toward a better understanding of the magmatic dynamics and has the potential to improve eruption forecasting.This research was supported by the Spanish Government (MICINN) projects: RECALDEC (CTM2009-05919-E/ANT), PEVOLDEC (CTM2011-13578-E/ANT), POSVOLDEC (CTM2016-79617-P)(AEI/FEDER, UE), VOLGASDEC (PGC2018-095693-B-I00)(AEI/FEDER, UE), HYDROCAL (PID2020-114876GB-I00)(MCIN/AEI/10.13039/501100011033), EruptING (PID2021-127189OB-I00) (MCIN/AEI/10.13039/501100011033), and Programa Propio’s project (Universidad de Salamanca-2019 modalidad 1B). A.A-V also thanks the JSPS invitation fellowship (S18113) at the University of Tokyo. A.P.S is grateful for his PhD grant “Programa Propio III Universidad de Salamanca-2021 cofounded by Banco de Santander”.Peer reviewe

Volcanism and climate change as drivers in Holocene depositional dynamic of Laguna del Maule (Andes of central Chile – 36° S)

Late Quaternary volcanic basins are active landscapes from which detailed archives of past climate and seismic and volcanic activity can be obtained. A multidisciplinary study performed on a transect of sediment cores was used to reconstruct the depositional evolution of the high-elevation Laguna del Maule (LdM) (36∘ S, 2180 m a.s.l., Chilean Andes). The recovered 5 m composite sediment sequence includes two thick turbidite units (LT1 and LT2) and numerous tephra layers (23 ash and 6 lapilli). We produced an age model based on nine new 14C AMS dates, existing 210Pb and 137Cs data, and the Quizapú ash horizon (1932 CE). According to this age model, the relatively drier Early Holocene was followed by a phase of increased productivity during the mid-Holocene and higher lake levels after 4.0 ka cal BP. Major hydroclimate transitions occurred at ca. 11, 8.0, 4.0 and 0.5 ka cal BP. Decreased summer insolation and winter precipitation due to a southward shift in the southern westerly winds and a strengthened Pacific Subtropical High could explain Early Holocene lower lake levels. Increased biological productivity during the mid-Holocene (∼8.0 to 6.0 ka cal BP) is coeval with a warm–dry phase described for much of southern South America. Periods of higher lake productivity are synchronous to a higher frequency of volcanic events. During the Late Holocene, the tephra layers show compositional changes suggesting a transition from silica-rich to silica-poor magmas at around 4.0 ka cal BP. This transition was synchronous with increased variability of sedimentary facies and geochemical proxies, indicating higher lake levels and increased moisture at LdM after 4.0 ka cal BP, most likely caused by the inception of current El Niño–Southern Oscillation and Pacific Decadal Oscillation (ENSO–PDO) dynamics in central Chile.Postprin

Noble gas signals in corals predict submarine volcanic eruptions

Deep-water corals growing in close proximity to the 2011 submarine eruption at Tagoro (El Hierro Island; Canary Archipielago, Spain) have revealed their ability to record the magmatic helium (3He) signal during a period of months prior to the eruption with magmatic 3He/4He ratios of 3.6-5.0 RA This is similar to the range of He isotope values (3-10 Ra) obtained from olivine samples from basinites erupted during the 2011 Tagoro eruption. Whip-like black corals (Anthozoa: Antipatharia: Antipathidae: Stichopathes) growing on basaltic rocks trapped 3He within their skeletons. We used a theoretical growth rate to estimate the time of trapping of 3He between release from the magmatic source at depth to trapping by the aquatic organisms. Our findings suggest that magmatic 3He emission occurred a few months before the beginning of the seismic activity in the region, the latter occurring four months in advance of the beginning of the eruption. This discovery implies that corals living in submarine volcanic areas may act as archives of noble gases released before the beginning of an eruption, and that the continuous monitoring of 3He may help to constrain the arrival time of a subaqueous eruption with potential applications in volcano eruption forecasting.En prens