Hydrothermal Alteration and Spring Water Geochemistry of Sebinkarahisar (Giresun, NE Turkey) Volcanic Field

AbstractSiliceous-sulphate rock coatings were observed at Zhenzhu Spring, an acid sulphate hot spring in the Tengchong volcanic field, China. These rock coatings are mainly formed of gypsum and amorphous silica. Some alum-(K), voltaite, α-quartz and muscovite were also found. Four different laminae are developed in the rock coatings: gypsum layer, tight siliceous layer, tabular siliceous layer and siliceous debris layer. The gypsum layer is located at the top of the rock coatings, while other siliceous layers appear below the gypsum layer. Geochemical modelling of the fluids was performed to identify the mechanisms responsible for the formation of gypsum and amorphous silica. The results indicated that the occurrence of gypsum is related to the acid-fog deposition and amorphous silica mainly originates from spring water. Fog deposition provided the rock coatings with abundant SO42− and Ca, and the subsequent complete evaporation of the condensed fluids produced gypsum. Seasonal climate change (especially variation in rainfall) determines the fluctuations of capillary action and dissolution. Rainfall events in the wet season led to periods of non-precipitating gypsum and promoted the capillary rise of the spring water. Slightly diluted capillary water (a small amount of rainwater) covered the rock coatings, formed a tight siliceous layer on the rock-coating surface and/or filled the pores among the gypsum crystals forming many tabular siliceous aggregates. Heavy rainfall (high dilution), however, resulted in non-precipitating amorphous silica and accelerated the gypsum dissolution, leaving tabular pores around tabular siliceous aggregates and forming a tabular siliceous layer.

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Discussion on “Relation between spring-water chemistry and hydrothermal alteration in the Saplica volcanic rocks, Sebinkarahisar (Giresun, Turkey)” [Journal of Geochemical Exploration, 2007, v. 93, p. 35–46]

Journal of Geochemical Exploration ◽

10.1016/j.gexplo.2008.03.006 ◽

2009 ◽

Vol 100 (1) ◽

pp. 90-92

Author(s):

Halim Mutlu

Keyword(s):

Water Chemistry ◽

Hydrothermal Alteration ◽

Volcanic Rocks ◽

Spring Water ◽

Geochemical Exploration

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GEOLOGIC CONTROLS ON GROUNDWATER FLOWPATHS IN THE SPRING MOUNTAINS, NV INFERRED FROM SPRING WATER GEOCHEMISTRY AND 87SR/86SR

10.1130/abs/2018am-319847 ◽

2018 ◽

Author(s):

Sara R. Warix ◽

◽

Laura K. Rademacher ◽

Zachary P. Meyers ◽

Marty D. Frisbee ◽

...

Keyword(s):

Spring Water ◽

Water Geochemistry ◽

Spring Mountains ◽

Groundwater Flowpaths ◽

Geologic Controls

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Subaerial sulfate mineral formation related to acid aerosols at the Zhenzhu Spring, Tengchong, China

Mineralogical Magazine ◽

10.1180/mgm.2018.164 ◽

2019 ◽

Vol 83 (03) ◽

pp. 381-392 ◽

Cited By ~ 1

Author(s):

Lianchao Luo ◽

Huaguo Wen ◽

Rongcai Zheng ◽

Ran Liu ◽

Yi Li ◽

...

Keyword(s):

Hot Spring ◽

Isotope Geochemistry ◽

Volcanic Field ◽

Geothermal Field ◽

Spring Water ◽

Acid Water ◽

Water Droplets ◽

Element Geochemistry ◽

Sulfate Minerals ◽

Intense Activity

AbstractThe Zhenzhu Spring, located in the Tengchong volcanic field, Yunnan, China, is an acid hot spring with high SO42−concentrations and intense acid aerosol generation. In order to understand the formation mechanism of sulfate minerals at the Zhenzhu Spring and provide a better insight into the sulfur isotope geochemistry of the associated Rehai hydrothermal system, we investigated the spring water hydrochemistry, mineralogy and major-element geochemistry of sulfate minerals at the Zhenzhu Spring together with the sulfur-oxygen isotope geochemistry of sulfur-containing materials at the Rehai geothermal field and compared the isotope results with those in other steam-heated environments. Subaerial minerals include a wide variety of sulfate minerals (gypsum, alunogen, pickeringite, tamarugite, magnesiovoltaite and a minor Mg–S–O phase) and amorphous SiO2. The δ34S values of the subaerial sulfate minerals at the Zhenzhu Spring varied subtly from –0.33 to 1.88‰ and were almost consistent with the δ34S values of local H2S (–2.6 to 0.6‰) and dissolved SO42−(–0.2 to 5.8‰), while the δ18O values (–8.94 to 20.1‰) were between that of the spring waters (–10.19 to –6.7‰) and atmospheric O2(~23.88‰). The results suggest that most of the sulfate minerals are derived from the oxidation of H2S, similar to many sulfate minerals from modern steam-heated environments. However, the rapid environmental change (different ratio of atmospheric and water oxygen) at the Zhenzhu Spring accounts for the large variation of δ18O. The formation of subaerial sulfate minerals around the Zhenzhu Spring is related to acid aerosols (vapour and acid water droplets). The intense activity of spring water around vents supply the aerosol with H2SO4(H2S oxidation and acid water droplets formed by bubble bursting) and few cations. Deposition of the acid sulfate aerosol forms the acid condensate, which attacks the underlying rocks and releases many cations and anions to form subaerial sulfate minerals at the Zhenzhu Spring.

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Spring Water Geochemistry: A Geothermal Exploration Tool in the Rhenohercynian Fold-and-Thrust Belt in Belgium

Geosciences ◽

10.3390/geosciences11110437 ◽

2021 ◽

Vol 11 (11) ◽

pp. 437

Author(s):

Marina Cabidoche ◽

Yves Vanbrabant ◽

Serge Brouyère ◽

Vinciane Stenmans ◽

Bruno Meyvis ◽

...

Keyword(s):

Spring Water ◽

Salinity Range ◽

Thrust Belt ◽

Water Geochemistry ◽

Geothermal Exploration ◽

Fold And Thrust Belt ◽

Geothermal Potential ◽

Geological Conditions ◽

Exploration Tool

Spring water geochemistry is applied here to evaluate the geothermal potential in Rhenohercynian fold and thrust belt around the deepest borehole in Belgium (Havelange borehole: 5648 m MD). Fifty springs and (few) wells around Havelange borehole were chosen according to a multicriteria approach including the hydrothermal source of “Chaudfontaine” (T ≈ 36 °C) taken as a reference for the area. The waters sampled, except Chaudfontaine present an in-situ T range of 3.66–14.04 °C (mean 9.83 °C) and a TDS (dry residue) salinity range of 46–498 mg/L. The processing methods applied to the results are: hierarchical clustering, Piper and Stiff diagrams, TIS, heat map, boxplots, and geothermometry. Seven clusters are found and allow us to define three main water types. The first type, locally called “pouhon”, is rich in Fe and Mn. The second type contains an interesting concentration of the geothermal indicators: Li, Sr, Rb. Chaudfontaine and Moressée (≈5 km East from the borehole) belong to this group. This last locality is identified as a geothermal target for further investigations. The third group represents superficial waters with frequently high NO3 concentration. The application of conventional geothermometers in this context indicates very different reservoir temperatures. The field of applications of these geothermometers need to be review in these geological conditions.

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