scholarly journals Volcanic Outgassing and Magmatic Volatiles

2020 ◽  
Author(s):  
Marie Edmonds
1981 ◽  
Vol 8 (7) ◽  
pp. 757-760 ◽  
Author(s):  
J. C. Eichelberger ◽  
H. R. Westrich
Keyword(s):  

Author(s):  
E.G. Kalacheva ◽  

This report provides a brief description of the field work on the Kuril Islands. It was performed within the framework of the R&D theme, projects of the RSF and the RFFR, which are realized in the laboratory of postmagmatic processes of the Institute of Volcanology and Seismology FEB RAS. Hydrological and hydrochemical works were performed on the rivers draining the slopes and thermal fields of the Sinarka, Kuntomintar volcanic massifs (Shiashkotan Island), and the Vernadsky and Karpinsky Ridges (Paramushir Island). The study of the chemical erosion of volcanic islands and the assessment of the hydrothermal export of magmatic volatiles are the goals of this work. Infrared photography was taken and the total flux of volcanic SO2 and diffusion flux of CO2 were measured on thermal fields in the caldera of Golovnin volcano. A detailed hydrogeochemical survey was made on the thermal fields of the Ebeko volcano to study the relationship of volcanic and hydrothermal activity of the volcano. For further analytical work, a large number of water and gas samples were taken and a representative collection of rocks and sediments was collected during the expedition.


1984 ◽  
pp. 35-58
Author(s):  
Richard V. Fisher ◽  
Hans-Ulrich Schmincke
Keyword(s):  

2021 ◽  
Author(s):  
Manuel Scherf ◽  
Herbert Lichtenegger ◽  
Sergey Dyadechkin ◽  
Helmut Lammer ◽  
Raven Adam ◽  
...  

<p>Mars likely had a denser atmosphere during the Noachian eon about 3.6 to 4.0 billion years ago (Ga). How dense this atmosphere might have been, and which escape mechanisms dominated its loss are yet not entirely clear. However, non-thermal escape processes and potential sequestration into the ground are believed to be the main drivers for atmospheric loss from the present to about 4.1 Ga.</p> <p>To evaluate non-thermal escape over the last ~4.1 billion years, we simulated the ion escape of Mars' CO<sub>2</sub> atmosphere caused by its dissociation products C and O atoms with numerical models of the upper atmosphere and its interaction with the solar wind (see Lichtenegger et al. 2021; https://arxiv.org/abs/2105.09789). We use the planetward-scattered pick-up ions for sputtering estimates of exospheric particles including <sup>36</sup>Ar and <sup>38</sup>Ar isotopes, and compare ion escape, with sputtering and photochemical escape rates. For solar EUV fluxes ≥3 times the present-day Sun (earlier than ~2.6 Ga) ion escape becomes the dominant atmospheric non-thermal loss process until thermal escape takes over during the pre-Noachian eon (earlier than ~4.0 - 4.1 Ga). If we extrapolate the total escape of CO<sub>2</sub>-related dissociation products back in time until ~4.1 Ga, we obtain a theoretical equivalent to CO<sub>2</sub> partial pressure of more than ~3 bar, but this amount did not necessarily have to be present and represents a maximum that could have been lost to space within the last ~4.1 Ga.</p> <p>Argon isotopes can give an additional insight into the evolution of the Martian atmosphere. The fractionation of <sup>36</sup>Ar/<sup>38</sup>Ar isotopes through sputtering and volcanic outgassing from its initial chondritic value of 5.3, as measured in the 4.1 billion years old Mars meteorite ALH 84001, until the present day can be reproduced for assumed CO<sub>2</sub> partial pressures between ~0.2-3.0 bar, depending on the cessation time of the Martian dynamo (assumed between 3.6-4.0 Ga) - if atmospheric sputtering of Ar started afterwards. The later the dynamo ceased away, the lower the pressure could have been to reproduce <sup>36</sup>Ar/<sup>38</sup>Ar.</p> <p>Prior to ~4.1 Ga (i.e., during the pre-Noachian eon), thermal escape should have been the most important driver of atmospheric escape at Mars, and together with non-thermal losses, might have prevented a stable and dense CO<sub>2</sub> atmosphere during the first ~400 million years. Our results indicate that, while Mars could have been warm and wet at least sporadically between ~3.6-4.1 Ga, it likely has been cold and dry during the pre-Noachian eon (see also Scherf and Lammer 2021; https://arxiv.org/abs/2102.05976).</p>


2021 ◽  
pp. 301-312
Author(s):  
Paul J. Wallace
Keyword(s):  

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 462 ◽  
Author(s):  
Takumi Imura ◽  
Yusuke Minami ◽  
Tsukasa Ohba ◽  
Akiko Matsumoto ◽  
Antonio Arribas ◽  
...  

Aluminum-phosphate-sulfates (APS) of the alunite supergroup occur in igneous rocks within zones of advanced argillic and silicic alteration in porphyry and epithermal ore environments. In this study we report on the presence of woodhouseite-rich APS in ash from the 27 September 2014 hydrothermal eruption of Ontake volcano. Scanning electron microscope coupled with energy dispersive X-ray spectrometer (SEM-EDS) and field emission (FE)-SEM-EDS observations show two types of occurrence of woodhouseite: (a) as cores within chemically zoned alunite-APS crystals (Zoned-alunite-woodhouseite-APS), and (b) as a coherent single-phase mineral in micro-veinlets intergrown with similar micro-veinlets of silica minerals (Micro-wormy-vein woodhouseite-APS). The genetic environment of APS minerals at Ontake volcano is that of a highly acidic hydrothermal system existing beneath the volcano summit, formed by condensation in magmatic steam and/or ground waters of sulfur-rich magmatic volatiles exsolved from the magma chamber beneath Mt. Ontake. Under these conditions, an advanced argillic alteration assemblage forms, which is composed of silica, pyrophyllite, alunite and kaolinite/dickite, plus APS, among other minerals. The discovery of woodhouseite in the volcanic ash of the Ontake 2014 hydrothermal eruption represents the first reported presence of APS within an active volcano. Other volcanoes in Japan and elsewhere with similar phreatic eruptions ejecting altered ash fragments will likely contain APS minerals derived from magmatic-hydrothermal systems within the subvolcanic environment. The presence of APS minerals within the advanced argillic zone below the summit vent of Ontake volcano, together with the prior documentation of phyllic and potassically altered ash fragments, provides evidence for the existence within an active volcano in Japan of an alteration column comparable to that of porphyry copper systems globally.


2011 ◽  
Vol 308 (3-4) ◽  
pp. 391-400 ◽  
Author(s):  
M. Grott ◽  
A. Morschhauser ◽  
D. Breuer ◽  
E. Hauber
Keyword(s):  

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