Genesis of Sulfate in Acid Hot Spring

Iwasaki, Iwaji; Ozawa, T.

doi:10.1246/bcsj.33.1018b

Cited by 29 publications

(18 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High concentration of CO 2 (14.5 mM), high SO 2 derived SO 4 2-(32.8 mM) and HF (135 mM) was reported in the presently active hydrothermal solution (Gamo et al, 1997;Ishibashi et al, 1998;Douville et al, 1999). At magmatic temperature sulphur gases are dominated by SO 2 (Sakai et al, 1984) and will undergo disproportionation reaction according to Iwasaki and Ozawa (1960) and Sakai and Matsubaya (1977) through the following reaction: 4SO 2 + 4H 2 O = 3H 2 SO 4 + H 2 S…”

Section: Origin Of Acid-sulphate Hydrothermal Fluidsmentioning

confidence: 96%

Acid‐sulphate Type Alteration and Mineralization in the Desmos Caldera, Manus Back‐arc Basin, Papua New Guinea

Gena¹,

Mizuta²,

Ishiyama³

et al. 2001

Resource Geology

View full text Add to dashboard Cite

Abstract:The Onsen acid-sulphate type of mineralization is located in the Desmos caldera, Manus back-arc basin. Hydrothermal precipitates, fresh and altered basaltic andesite collected from the Desmos caldera were studied to determine mineralization and mobility of elements under seawater dominated condition of hydrothermal alteration.The mineralization is characterized by three stages of advanced argillic alteration. Alteration stage I is characterized by coarse subhedral pyrophyllite with disseminated anhedral pyrite and enargite which were formed in the temperature range of 260-340°C. Alteration stage II which overprinted alteration stage I was formed in the temperature range of 270-310°C and is characterized by euhedral pyrite, quartz, natroalunite, cristobalite and mixed layer minerals of smectite and mica with 14-15 Å XRD peak. Alteration stage III is characterized by amorphous silica, native sulphur, covellite, marcasite and euhedral pyrite, which has overprinted alteration stages I and II.Relative to the fresh basaltic andesite samples, the rims and cores of the partly altered basaltic andesite samples have very low major, minor and rare earth elements content except for SiO 2 which is much higher (58-78 wt%) than SiO 2 content of the fresh basaltic andesite (55 wt%). REE patterns of the partly altered basaltic andesite specimens are variably depleted in LREE and have pronounced negative Eu anomalies. Normalization of major, minor and REE content of the partly altered basaltic andesites to the fresh basaltic andesite indicates that all the elements except for SiO 2 in the partly altered basaltic andesite are strongly lost (e.g. Al 2 O 3 = -8.3 to -10.9 g/100cm 3 , Ba = -2.2 to -5.6 mg/100cm 3 , La = -130 to -200 µg/100cm 3 ) during the alteration process. Abnormal depletion of MgO, total Fe as Fe 2 O 3 , LREE especially Eu and enrichment of SiO 2 in the altered basaltic andesites from the Desmos caldera seafloor is caused by interaction of hot acidic hydrothermal fluid, which originates from a mixing of magmatic fluid and seawater.

show abstract

Section: Origin Of Acid-sulphate Hydrothermal Fluidsmentioning

confidence: 96%

Acid‐sulphate Type Alteration and Mineralization in the Desmos Caldera, Manus Back‐arc Basin, Papua New Guinea

Gena¹,

Mizuta²,

Ishiyama³

et al. 2001

Resource Geology

View full text Add to dashboard Cite

show abstract

“…In contrast to basaltic magmas, where it exists mostly as sulfide, total S in more oxidizing (higher f O2 ) calc-alkaline magmas is predominantly in the forms SO 2 and SO 4 (Burnham, 1979;Carroll and Rutherford, 1988;Nilsson and Peach, 1993;Carroll and Webster, 1994). SO 2 strongly partitions into exsolved aqueous fluids during magmatic degassing (Burnham, 1979;Scaillet and Pichavant, 2003) and upon cooling below ~400°C, SO 2 can undergo either of the following disproportionation reactions (Iwasaki and Takejiro, 1960;Holland, 1965;Drummond, 1981;Kusakabe et al, 2000):…”

Section: Magmatic So 2 Input and Disproportionationmentioning

confidence: 99%

Laboratory and field-based investigations of subsurface geochemical processes in seafloor hydrothermal systems

Reeves¹

2010

View full text Add to dashboard Cite

This thesis presents the results of four discrete investigations into processes governing the organic and inorganic chemical composition of seafloor hydrothermal fluids in a variety of geologic settings. Though Chapters 2 through 5 of this thesis are disparate in focus, each represents a novel investigation aimed at furthering our understanding of subsurface geochemical processes affecting hydrothermal fluid compositions. Chapters 2 and 3 concern the abiotic (nonbiological) formation of organic compounds in high temperature vent fluids, a process which has direct implications for the emergence of life in early Earth settings and sustainment of present day microbial populations in hydrothermal environments. Chapter 2 represents an experimental investigation of methane (CH 4 ) formation under hydrothermal conditions. The overall reduction of carbon dioxide (CO 2 ) to CH 4 , previously assumed to be kinetically inhibited in the absence of mineral catalysts, is shown to proceed on timescales pertinent to crustal residence times of hydrothermal fluids. In Chapter 3, the abundance of methanethiol (CH 3 SH), considered to be a crucial precursor for the emergence of primitive chemoautotrophic life, is characterized in vent fluids from ultramafic-, basalt-and sediment-hosted hydrothermal systems. Previous assumptions that CH 3 SH forms by reduction of CO 2 are not supported by the observed distribution in natural systems. Chapter 4 investigates factors regulating the hydrogen isotope composition of hydrocarbons under hydrothermal conditions. Isotopic exchange between low molecular weight n-alkanes and water is shown to be facilitated by metastable equilibrium reactions between alkanes and their corresponding alkenes, which are feasible in natural systems. In Chapter 5, the controls on vent fluid composition in a backarc hydrothermal system are investigated. A comprehensive survey of the inorganic geochemistry of fluids from sites of hydrothermal activity in the eastern Manus Basin indicates that fluids there are influenced by input of acidic magmatic solutions at depth, and subsequently modified by variable extents of seawater entrainment and mixing-related secondary acidity production. CHAPTER 1 IntroductionSeafloor hydrothermal systems associated with the generation of oceanic crust represent a dramatic expression of heat and mass transfer from the interior of the Earth. In addition to profound effects on ocean chemistry, convective circulation of seawater through volcanically active oceanic crust leads to the formation of metal sulfide deposits. In addition, seafloor hot springs are often invoked as ideal settings from which early microbial life could have emerged.Since the initial discovery of low temperature venting at the Galápagos Spreading Center in 1977 (CORLISS et al., 1979), our understanding of the composition and diversity of hydrothermal solutions has expanded greatly. During convection through oceanic crust of basaltic composition, O 2 -replete seawater reacts with crustal rock, typically producin...

show abstract

“…The several grams of sulfate per liter often contained in hot spring water cannot be explained to have been supplied solely by atmospheric oxidation of hydrogen sulfide and sulfur dioxide. IWASAKI and OZAWA (1960) introduced the disproportionation reaction of sul furous acid, 3 H2SO3=2 H2SO4+S+H20, to explain the occurrence of sulfate in hot spring water.…”

Section: Introductionmentioning

confidence: 99%

Sulfur isotopic fractionation between sulfur and sulfuric acid in the hydrothermal solution of sulfur dioxide

Oana

Ishikawa

1966

Geochem. J.

View full text Add to dashboard Cite

Genesis of Sulfate in Acid Hot Spring

Cited by 29 publications

References 1 publication

Acid‐sulphate Type Alteration and Mineralization in the Desmos Caldera, Manus Back‐arc Basin, Papua New Guinea

Acid‐sulphate Type Alteration and Mineralization in the Desmos Caldera, Manus Back‐arc Basin, Papua New Guinea

Laboratory and field-based investigations of subsurface geochemical processes in seafloor hydrothermal systems

Sulfur isotopic fractionation between sulfur and sulfuric acid in the hydrothermal solution of sulfur dioxide

Contact Info

Product

Resources

About