Oxygen, hydrogen, and sulfur isotope systematics of the crater lake system of Poas Volcano, Costa Rica.

Rowe, Jr. Gary L.

doi:10.2343/geochemj.28.263

Cited by 47 publications

(6 citation statements)

References 50 publications

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“…Thus, for the case of open vent volcanoes we consider magmatic gases to be more representative of the primary S isotope composition than scoria or lavas. High-temperature gas samples from Momotombo (Ba/La > 100) [Carr and Rose, 1987], located S of Masaya, have 34 S values of þ4.2 to þ6.8% [Menyailov et al, 1986] (comparing well with our Momotombo gas value of þ6.2%; see section 3.2) and high-temperature SO 2 from Poas volcano in Costa Rica has 34 S values of $þ7% [Rowe, 1994]. The SO 2 flux from Masaya represents $23% of the total SO 2 flux from the Central American arc [Hilton et al, 2002;Mather et al, 2006b] and we thus consider a value of þ5% to be a reasonable representative of S emitted from the Central American arc segment.…”

Section: Implications For S Isotope Fractionation and S Sources In Ma...supporting

confidence: 75%

Sulfur degassing at Erta Ale (Ethiopia) and Masaya (Nicaragua) volcanoes: Implications for degassing processes and oxygen fugacities of basaltic systems

Moor

Fischer

Sharp

et al. 2013

Geochem Geophys Geosyst

114

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/ P S with extent of S degassing at Erta Ale, indicating negligible effect on fO 2 , and further suggesting that H 2 S is the dominant gas species exsolved from the S 2À -rich melt (i.e., no redistribution of electrons). High SO 2 /H 2 S observed in Erta Ale gas emissions is due to gas re-equilibration at low pressure and fixed fO 2. Sulfur budget considerations indicate that the majority of S injected into the systems is emitted as gas, which is therefore representative of the magmatic S isotope composition. The composition of the Masaya gas plume (þ4.8%) cannot be explained by fractionation effects but rather reflects recycling of high 34 S oxidized sulfur through the subduction zone.

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Section: Implications For S Isotope Fractionation and S Sources In Ma...supporting

confidence: 75%

Sulfur degassing at Erta Ale (Ethiopia) and Masaya (Nicaragua) volcanoes: Implications for degassing processes and oxygen fugacities of basaltic systems

Moor

Fischer

Sharp

et al. 2013

Geochem Geophys Geosyst

114

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“…This value is the first result for δ 34 S reported for Lastarria volcano; it is fairly light compared to average MORB glasses (-0.91‰ ± 0.50‰; Fischer et al, 1998). The obtained value of -6.10‰ is heavier than the range observed for elemental sulfur at Poás (-12.3 to -9.4‰; Oppenheimer, 1992;Rowe, 1994) and within the range (-9 to +7‰; Ueda et al, 1979) obtained for 44 different volcanic sites in Japan. Then, our δ 34 S value is closer to the lighter values found in floating spherules at Kawah Ijen (-4.2 to -1.4‰; Delmelle et al, 2000;Kusakabe et al, 2000) and subsurface native sulfur at Campi Flegrei (-5.5‰ to 0‰; Piochi et al, 2015).…”

Section: Sulfur Isotopic Compositionsupporting

confidence: 52%

Physical and chemical characteristics of active sulfur flows observed at Lastarria volcano (northern Chile) in January 2019

Inostroza¹,

Fernández

Aguilera

et al. 2023

Front. Earth Sci.

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Molten sulfur is found in various subaerial volcanoes. However, limited records of the pools and flows of molten sulfur have been reported: therefore, questions remain regarding the physicochemical processes behind this phenomenon. A suite of new sulfur flows, some of which active, was identified at the Lastarria volcano (northern Chile) and studied using satellite imagery, in situ probing, and temperature and video recording. This finding provides a unique opportunity to better understand the emplacement mechanisms and mineral and chemical compositions of molten sulfur, in addition to gaining insight into its origin. Molten sulfur presented temperatures of 124–158°C, with the most prolonged sulfur flow reaching 12 m from the source. Photogrammetric tools permitted the identification of levees and channel structures, with an estimated average flow speed of 0.069 m/s. Field measurements yielded a total volume of 1.45 ± 0.29 m3 of sulfur (equivalent to ∼2.07 tons) mobilized during the January 2019 event for at least 408 min. Solidified sulfur was composed of native sulfur with minor galena and arsenic- and iodine-bearing minerals. Trace element analysis indicated substantial enrichment of Bi, Sb, Sn, Cd, as well as a very high concentration of As (>40.000 ppm). The January 2019 molten sulfur manifestations in Lastarria appear to be more enriched in As compared to the worldwide known volcanoes with molten sulfur records, such as the Shiretoko-Iozan and Poás volcanoes. Furthermore, their rheological properties suggest that the “time of activity” in events such as this could be underestimated as flows in Lastarria have moved significantly slower than previously thought. The origin of molten sulfur is ascribed to the favorable S-rich chemistry of fumarolic gases and changes in host rock permeability (fracture opening). Molten sulfur in Lastarria correlates with a peak in activity characterized by high emissions of SO2 and other acid species, such as HF and HCl, in addition to ground deformation. Consequently, molten sulfur was framed within a period of volcanic unrest in Lastarria, triggered by changes in the magmatic-hydrothermal system. The appearance of molten sulfur is related to physicochemical perturbations inside the volcanic system and is perhaps a precursor of eruptive activity, as observed in the Poás and Turrialba volcanoes.

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“…Incidentally, although the main water source of any crater lake is generally meteoric precipitation, Yugama Crater Lake water is more enriched in δD and δ 18 O than the local meteoric water, and the δD/δ 18 O slope is 4.7 (Figure 9A). This slope very much resembles the slope of about 5, which typically results from the evaporation of lake water at ambient temperature (e.g., Matsubaya and Sakai, 1978;Rowe, 1994;Balistrieri et al, 2007). According to Ohba et al (2000), however, this isotopic enrichment mainly results from evaporation, but there is a small contribution of isotopically heavy Cl-rich fluids.…”

Section: Hcl Input Into the Hydrothermal Reservoirmentioning

confidence: 58%

“…In other words, fresh magma or actively degassing volcanic systems are not necessarily required to trigger phreatic eruptions. The water temperature in the Yugama Crater Lake has remained relatively cold for decades, although it once reached 55.5 °C just after the eruption in 1982 (Tokyo Institute of Technology et al, 1983), compared to the hyperacid lake of Poás volcano (up to 94 °C; Rowe, 1994), where magmatic or phreatomagmatic eruptions occur. This seems to support the idea that the contact between groundwater and the hot plastic rocks, which triggered the recent phreatic eruptions at Yugama Crater Lake, was not caused by magma intrusion, or magma intrusions at Yugama Crater Lake might be fairly small in volume with no critical mass to destabilize the hydrothermal system and trigger eruptions.…”

Section: Self-sealing Zone Breach Due To Magmatic Fluids Ascendmentioning

confidence: 99%

Groundwater Interacting at Depth With Hot Plastic Magma Triggers Phreatic Eruptions at Yugama Crater Lake of Kusatsu-Shirane Volcano (Japan)

2021

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Interpreting the triggering mechanisms for phreatic eruptions is a key to improving the hazard assessment of crater lakes. Yugama Crater Lake at Kusatsu-Shirane volcano, Japan, is the site of frequent phreatic eruptions with the recent eruptions in 1982–83, 1989, and 1996, as well as volcanic unrest, including earthquake swarms in 2014 and 2018. To understand the magma–hydrothermal interaction beneath Yugama Crater Lake, we analyzed lake waters from November 2005 to May 2021. From 2005 to 2012, Cl and SO4 concentrations decreased slowly, suggesting the development of a self-sealing zone surrounding the crystallizing magma. We focused on Ca, Al, and Si concentrations as representatives of the breach and dissolution of minerals comprising the self-sealing zone and the Mg/Cl ratio as an indicator for enhanced interaction between groundwater and hot plastic rock within the self-sealing zone. In 2006–2007, the Ca, Al, Si concentrations and the Mg/Cl ratio increased. No Cl and SO4 increase during this period suggests the self-sealing zone was leached by deep circulating groundwater rather than by magmatic fluids injection. After the 2014 earthquakes, Ca, Al, and Si increased again but were associated with a significant Cl increase and a pH decrease. We believe that the HCl-rich magmatic fluids breached the self-sealing zone, leading to fluids injection from the crystallizing magma to the Yugama crater. During this period, the Mg/Cl ratio did not increase, meaning that magmatic fluids ascending from the breached area of the self-sealing zone inhibited deep intrusion of groundwater into the hot plastic rock region. In 2018, magmatic fluids ascended through the self-sealing zone again with less intensity than in 2014. All eruptions since 1982 have been accompanied by a Mg/Cl ratio increase and a Cl decrease, whereas, when a significant HCl input occurs, as in 2014, no eruptions and no Mg/Cl ratio increase occurred. This demonstrates that the groundwater–hot plastic rock interaction, rather than the magmatic fluids input, played an essential role in triggering phreatic eruptions; i.e., phreatic eruptions can potentially occur without clear signs of fresh magma intrusions.

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Oxygen, hydrogen, and sulfur isotope systematics of the crater lake system of Poas Volcano, Costa Rica.

Cited by 47 publications

References 50 publications

Sulfur degassing at Erta Ale (Ethiopia) and Masaya (Nicaragua) volcanoes: Implications for degassing processes and oxygen fugacities of basaltic systems

Sulfur degassing at Erta Ale (Ethiopia) and Masaya (Nicaragua) volcanoes: Implications for degassing processes and oxygen fugacities of basaltic systems

Physical and chemical characteristics of active sulfur flows observed at Lastarria volcano (northern Chile) in January 2019

Groundwater Interacting at Depth With Hot Plastic Magma Triggers Phreatic Eruptions at Yugama Crater Lake of Kusatsu-Shirane Volcano (Japan)

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