scholarly journals Geology and Fluid Discharge at Dorado Outcrop, a Low Temperature Ridge‐Flank Hydrothermal System

2019 ◽  
Vol 20 (1) ◽  
pp. 487-504 ◽  
Author(s):  
C. Geoffrey Wheat ◽  
Anne M. Hartwell ◽  
James McManus ◽  
Andrew T. Fisher ◽  
Beth N. Orcutt ◽  
...  
Keyword(s):  
Low Temperature ◽  
Hydrothermal System ◽  
Ridge Flank

Environmental controls on biomineralization and Fe-mound formation in a low-temperature hydrothermal system at the Jan Mayen Vent Fields

2017 ◽  
Vol 202 ◽  
pp. 101-123 ◽  
Author(s):  
Karen C. Johannessen ◽  
Jan Vander Roost ◽  
Håkon Dahle ◽  
Siv H. Dundas ◽  
Rolf B. Pedersen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Hydrothermal System ◽  
Environmental Controls ◽  
Mound Formation

Mineral Associations of Veins with Quartz of the "Diamonds оf Donbass" Type in the Seleznevsky Coal-Bearing District (Folded Donbass)

2021 ◽  
pp. 66-72
Author(s):  
Oleg S. Krisak ◽  
Yuri V. Popov
Keyword(s):  
Low Temperature ◽  
Hydrothermal System ◽  
Third Order ◽  
Quartz Crystals ◽  
The Third ◽  
Hydrothermal Mineralization ◽  
Water Composition ◽  
Mineral Associations

The authors have established quartz and quartz-carbonate veins, the formation of which is associated with a low-temperature hydrothermal system of methane-water composition within the Seleznevsky coal-bearing region of the Folded Donbass. The article considers the features of localization of hydrothermal mineralization containing quartz with inclusions of hydrocarbons, and its potential ore content. It is established that the vein bodies are localized mainly in the near-hinge parts of the third-order brachianticlines in the central and marginal parts of the Seleznevskaya syncline. These veins form systems associated with the fracturing of the inter-layer stratification or intersecting the layers. Interplastic veins are subdivided into plate-like massive and vein-like bodies with a druze texture. The veins of the second type contain quartz crystals with hydrocarbon inclusions, referred to as "diamonds of Donbass". They form a paragenetic association with dickite. In addition, calcite in the form of short-prismatic crystals is a typical associated mineral in the vein bodies among limestone strata. In the veins among the sandstone layers, the association with goethite, oxides and hydroxides of manganese is developed. Two morphological types of cinnabar were found in the vein bodies on the basis of HMS sampling, the largest number is confined to the brachianticlines of the marginal parts of the Seleznevskaya syncline. The analysis of the results indicates the prospects for identifying mercury mineralization with quartz-dickite-cinnabar type of mineralization.

scholarly journals Fluid chemistry of the low temperature hyperalkaline hydrothermal system of Prony Bay (New Caledonia)

2014 ◽  
Vol 11 (20) ◽  
pp. 5687-5706 ◽  
Author(s):  
C. Monnin ◽  
V. Chavagnac ◽  
C. Boulart ◽  
B. Ménez ◽  
M. Gérard ◽  
...  
Keyword(s):  
Low Temperature ◽  
Marine Environment ◽  
Water Samples ◽  
Hydrothermal System ◽  
New Caledonia ◽  
Water Discharge ◽  
The Other ◽  
Chemical Compositions ◽  
Saturation State ◽  
High Ph

Abstract. The terrestrial hyperalkaline springs of Prony Bay (southern lagoon, New Caledonia) have been known since the nineteenth century, but a recent high-resolution bathymetric survey of the seafloor has revealed the existence of numerous submarine structures similar to the well-known Aiguille de Prony, which are also the location of high-pH fluid discharge into the lagoon. During the HYDROPRONY cruise (28 October to 13 November 2011), samples of waters, gases and concretions were collected by scuba divers at underwater vents. Four of these sampling sites are located in Prony Bay at depths up to 50 m. One (Bain des Japonais spring) is also in Prony Bay but uncovered at low tide and another (Rivière des Kaoris spring) is on land slightly above the seawater level at high tide. We report the chemical composition (Na, K, Ca, Mg, Cl, SO4, dissolved inorganic carbon, SiO2(aq)) of 45 water samples collected at six sites of high-pH water discharge, as well as the composition of gases. Temperatures reach 37 °C at the Bain des Japonais and 32 °C at the spring of the Kaoris. Gas bubbling was observed only at these two springs. The emitted gases contain between 12 and 30% of hydrogen in volume of dry gas, 6 to 14% of methane, and 56 to 72% of nitrogen, with trace amounts of carbon dioxide, ethane and propane. pH values and salinities of all the 45 collected water samples range from the seawater values (8.2 and 35 g L−1) to hyperalkaline freshwaters of the Ca-OH type (pH 11 and salinities as low as 0.3 g L−1) showing that the collected samples are always a mixture of a hyperalkaline fluid of meteoric origin and ambient seawater. Cl-normalized concentrations of dissolved major elements first show that the Bain des Japonais is distinct from the other sites. Water collected at this site are three component mixtures involving the high-pH fluid, the lagoon seawater and the river water from the nearby Rivière du Carénage. The chemical compositions of the hyperalkaline endmembers (at pH 11) are not significantly different from one site to the other although the sites are several kilometres away from each other and are located on different ultramafic substrata. The very low salinity of the hyperalkaline endmembers shows that seawater does not percolate through the ultramafic formation. Mixing of the hyperalkaline hydrothermal endmember with local seawater produces large ranges and very sharp gradients of pH, salinity and dissolved element concentrations. There is a major change in the composition of the water samples at a pH around 10, which delimitates the marine environment from the hyperalkaline environment. The redox potential evolves toward negative values at high pH indicative of the reducing conditions due to bubbling of the H2-rich gas. The calculation of the mineral saturation states carried out for the Na-K-Ca-Mg-Cl-SO4-DIC-SiO2-H2O system shows that this change is due to the onset of brucite formation. While the saturation state of the Ca carbonates over the whole pH range is typical of that found in a normal marine environment, Mg- and Mg-Ca carbonates (magnesite, hydromagnesite, huntite, dolomite) exhibit very large supersaturations with maximum values at a pH of around 10, very well marked for the Bain des Japonais, emphasizing the role of water mixing in mineral formation. The discharge of high-pH waters of meteoric origin into the lagoon marine environment makes the hydrothermal system of Prony Bay unique compared to other low temperature serpentinizing environments such as Oman (fully continental) or Lost City (fully marine).

scholarly journals Chemosynthetic origin of 14C-depleted dissolved organic matter in a ridge-flank hydrothermal system

2010 ◽  
Vol 4 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Matthew D. McCarthy ◽  
Steven R. Beaupré ◽  
Brett D. Walker ◽  
Ian Voparil ◽  
Thomas P. Guilderson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Hydrothermal System ◽  
Ridge Flank

scholarly journals Hydrothermal fields of the Piip submarine volcano, Komandorsky Back-Arc Basin: Chemistry and origin of vent mineralization and bubbling gas

1994 ◽  
Vol 41 ◽  
pp. 55-64
Author(s):  
Pavel V. Torokhov ◽  
Yuri A. Taran
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Isotopic Composition ◽  
Significant Role ◽  
Hydrothermal System ◽  
Submarine Volcano ◽  
Bacterial Sulphate Reduction ◽  
Back Arc ◽  
Hydrothermal Fields

Active thermal vents of the Piip submarine volcano were studied in 1990 from aboard sub­mersibles MIR 1 and 2. Samples of free gas and hydrothermal deposits were collected in the areas of thermal fluid discharge. Mineralogical, isotopic and microprobe studies of samples have shown, as the hydrothermal system cools, the high-temperature anhydrite association displayed at the surface is substituted by calcite-barite and later by calcite-barite-sulfide assemblages. The chemical and isotopic composition of gas and carbonates indicates the significant role of hydrocarbons from the sedimentary layers which, during the low-temperature stage, stimulate the processes of bacterial sulphate reduction. The evolution of a simular hydrothermal system is traced in the Great Caucasus barite deposits.

scholarly journals Nitrification in a Young Ridge Flank Hydrothermal System

2020 ◽  
Author(s):  
Steffen Jørgensen ◽  
Rui Zhao ◽  
Gustavo Ramirez ◽  
Håkon Dahle
Keyword(s):  
Hydrothermal System ◽  
Ridge Flank
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