Resolving Io’s Volcanoes from a Mutual Event Observation at the Large Binocular Telescope

Unraveling the geological processes ongoing at Io’s numerous sites of active volcanism requires high spatial resolution to, for example, measure the areal coverage of lava flows or identify the presence of multiple emitting regions within a single volcanic center. In de Kleer et al. (2017) we described observations with the Large Binocular Telescope during an occultation of Io by Europa at ∼6:17 UT on 2015 March 8 and presented a map of the temperature distribution within Loki Patera derived from these data. Here we present emission maps of three other volcanic centers derived from the same observation: Pillan Patera, Kurdalagon Patera, and the vicinity of Ulgen Patera/PV59/N Lerna Regio. The emission is localized by the light curves and resolved into multiple distinct emitting regions in two of the cases. Both Pillan and Kurdalagon Paterae had undergone eruptions in the months prior to our observations, and the location and intensity of the emission are interpreted in the context of the temporal evolution of these eruptions observed from other facilities. The emission from Kurdalagon Patera is resolved into two distinct emitting regions separated by only a few degrees in latitude that were unresolved by Keck observations from the same month.

Active volcanism in Colombia and the role of the Servicio Geológico Colombiano

The Servicio Geológico Colombiano (SGC) was created in 1916 and has been dedicated to the research and monitoring of active volcanoes in the country since the disaster resulting from the eruption of Nevado del Ruíz Volcano in 1985, where more than 25000 people died due to lahars. Today the SGC has three Volcanological and Seismological Observatories in the cities of Manizales (SGC-OVSM), Popayán (SGC-OVSPop), and Pasto (SGC-OVSP), from where 23 active volcanoes are monitored. The three observatories manage an instrumental network of about 740 stations (permanent and portable) as well as signal repeaters, and cover the disciplines of seismology, geodesy, geochemistry, and potential field, amongst others. Volcanic hazard assessment is also carried out by the SGC, producing hazard maps and reports. These tasks are complemented by programs for promoting geoscience knowledge transfer to the public, developed through different strategies. Although at this time, data derived from volcanic monitoring are not available online, the SGC is analysing this need, for implementation in the near future. El Servicio Geológico Colombiano (SGC) fue creado en 1916, y se ha dedicado a la investigación y monitoreo de los volcanes activos en el país desde el desastre resultante de la erupción del volcán Nevado del Ruíz en 1985, donde más de 25000 personas murieron debido a la ocurrencia de lahares. Hoy en día, el SGC tiene tres Observatorios Vulcanológicos y Sismológicos en las ciudades de Manizales (SGC-OVSM), Popayán (SGC-OVSPop) y Pasto (SGC-OVSP), desde donde se monitorean 23 volcanes activos. Los tres observatorios manejan una red instrumental de aproximadamente 740 estaciones (permanentes y portátiles), como también repetidoras de señal, y cubren las disciplinas de sismología, geodesia, geoquímica y campos de potencial, entre otras. La evaluación de la amenaza volcánica también es realizada por el SGC, produciendo mapas e informes. Estas tareas se complementan con programas para promover transferencia de conocimientos geocientíficos al público, desarrollados a través de diferentes estrategias. Aunque en este momento los datos derivados del monitoreo volcánico no están disponibles en línea, el SGC está analizando esta necesidad para su implementación en un futuro cercano.

Volcanically extruded phosphides as an abiotic source of Venusian phosphine

We hypothesize that trace amounts of phosphides formed in the mantle are a plausible abiotic source of the Venusian phosphine observed by Greaves et al. [Nat. Astron., https://doi.org/10.1038/s41550-020-1174-4 (2020)]. In this hypothesis, small amounts of phosphides (P3− bound in metals such as iron), sourced from a deep mantle, are brought to the surface by volcanism. They are then ejected into the atmosphere in the form of volcanic dust by explosive volcanic eruptions, which were invoked by others to explain the episodic changes of sulfur dioxide seen in the atmosphere [Esposito, Science 223, 1072–1074 (1984)]. There they react with sulfuric acid in the aerosol layer to form phosphine (2 P3− + 3H2SO4 = 2PH3 + 3SO42-). We take issue with the conclusion of Bains et al. [arXiv:2009.06499 (2020)] that the volcanic rates for such a mechanism would have to be implausibly high. We consider a mantle with the redox state similar to the Earth, magma originating deep in the mantle—a likely scenario for the origin of plume volcanism on Venus—and episodically high but plausible rates of volcanism on a Venus bereft of plate tectonics. We conclude that volcanism could supply an adequate amount of phosphide to produce phosphine. Our conclusion is supported by remote sensing observations of the Venusian atmosphere and surface that have been interpreted as indicative of currently active volcanism.

Chapter 5.2a Erebus Volcanic Province: volcanology

The Erebus Volcanic Province is the largest Neogene volcanic province in Antarctica, extending c. 450 km north–south and 170 km wide east–west. It is dominated by large central volcanoes, principally Mount Erebus, Mount Bird, Mount Terror, Mount Discovery and Mount Morning, which have sunk more than 2 km into underlying sedimentary strata. Small submarine volcanoes are also common, as islands and seamounts in the Ross Sea (Terror Rift), and there are many mafic scoria cones (Southern Local Suite) in the Royal Society Range foothills and Dry Valleys. The age of the volcanism ranges between c. 19 Ma and present but most of the volcanism is <5 Ma. It includes active volcanism at Mount Erebus, with its permanent phonolite lava lake. The volcanism is basanite–phonolite/trachyte in composition and there are several alkaline petrological lineages. Many of the volcanoes are pristine, predominantly formed of subaerially erupted products. Conversely, two volcanoes have been deeply eroded. That at Minna Hook is mainly glaciovolcanic, with a record of the ambient mid–late Miocene eruptive environmental conditions. By contrast, Mason Spur is largely composed of pyroclastic density current deposits, which accumulated in a large mid-Miocene caldera that is now partly exhumed.

Dust arriving in the Amazon basin over the past 7,500 years came from diverse sources

A large amount of dust from the Sahara reaches the Amazon Basin, as observed with satellite imagery. This dust is thought to carry micronutrients that could help fertilize the rainforest. However, considering different atmospheric transport conditions, different aridity levels in South America and Africa and active volcanism, it is not clear if the same pathways for dust have occurred throughout the Holocene. Here we present analyses of Sr-Nd isotopic ratios of a lacustrine sediment core from remote Lake Pata in the Amazon region that encompasses the past 7,500 years before present, and compare these ratios to dust signatures from a variety of sources. We find that dust reaching the western Amazon region during the study period had diverse origins, including the Andean region and northern and southern Africa. We suggest that the Sahara Desert was not the dominant source of dust throughout the vast Amazon basin over the past 7,500 years.

Genetically different organogenic buildups in isotope values δ 13С and δ 18О

The isotopic composition of carbon and oxygen of 165 samples of carbonate rocks of genetically different organogenic structures: the Upper Ordovician Bol'shaya Kos'yu reef, the Upper Devonian Shar'yu microbial mound, the Kozhym skeletal mound, the Upper Miocene Kazantip bioherm complex and deep-water organogenic-carbonate structures of the north of the Mid-Atlantic Ridge was studied. The reef and microbial mound are characterized by δ 13СPDB values within the limits close to normal-sedimentary marine carbonates (–0.33—3.13 ‰) and (0.8—3.0 ‰), but with significant variations in δ 18ОSMOW — (22.24—30.0 ‰) and (20.4—26.3 ‰), respectively. The most isotopically-heavy carbon composition (5.1—7.3 ‰) in combination with varying δ 18ОSMOWvalues (22.4— 30.0 ‰) is characteristic of limestones and brachiopods of the skeletal mound. Fluctuations of δ 13СPDB and δ 18ОSMOW values in carbonate rocks of the Kazantip bioherm complex are the most expressive (–2.76—7.17 ‰) and (24.20—33.1 ‰), respectively. Deepwater organogenic structures from the bottom of the axial zone with active volcanism, in contrast to others, showed stable δ 13СPDB values (–0.98—0.83 ‰) within the area of normal-sedimentary marine carbonates, whereas for oxygen the values are istopic-heavy (32.27—39.75 ‰). As a result, the specificity of the development of the objects under study, established by lithological-paleoecological and chemical-physical methods, found its substantiation in isotopic values, paleosalinity and paleotemperatures caused by paleogeographic and climatic conditions.

Geoheritage and Geotourism in Regions with Extinct Volcanism in Germany; Case Study Southwest Germany with UNESCO Global Geopark Swabian Alb

Geotourism has become more popular in recent decades. Volcanism is an essential part of geoheritage and attracts a high number of visitors. In contrast to active volcanism, Tertiary volcanism is often not identified as such by a lay audience and is understandably perceived as less spectacular. The challenge is therefore to protect the volcanic heritage, to communicate its values, and to enhance it with the help of adequate geotourism offers. Germany does not have active volcanism, but a very high quality volcanic geological heritage, especially from the Tertiary period. Fortunately, this heritage is being increasingly valued and presented in an attractive way for a lay audience. The two Geoparks in the Eifel (Rhineland-Palatinate) are pioneers in this field. The UNESCO Global Geopark Swabian Alb actually offers a well camouflaged potential. The Swabian volcano, with an area of 1600 km2, is one of the most important tuff vent areas on earth, but hardly known outside of expert groups. A comprehensive strategy for the geotouristic valorization of the Tertiary volcanic phenomena does not yet exist in the Geopark Swabian Alb.