The chemistry of geothermal waters in Iceland. I. Calculation of aqueous speciation from 0° to 370°C

Arnórsson, Stefán; Sigurdsson, S.; Svavarsson, Hördur

doi:10.1016/0016-7037(82)90311-8

Cited by 235 publications

(54 citation statements)

References 34 publications

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“…Such methodology corrects the effect of the separation and segregation of liquid and vapor phases driven by adhesion of the liquid phase onto mineral surfaces in the porous aquifer rock upon rapid depressurization boiling. The reconstruction was performed using the WATCH geochemical modeling software (Arnórsson et al, 1982), assuming a unique segregation step and using temperature measurements to constrain reservoir temperature. The reconstructed chemistry was obtained for major elements included in the thermodynamic database of WATCH which are: SiO 2 , B, Na, K, Ca, Mg, Al, Fe, CO 2 , H 2 S, SO 4 , Cl and F.…”

Section: Gold Solubility Calculations In Pressure-enthalpy Spacementioning

confidence: 99%

The optimal windows for seismically-enhanced gold precipitation in the epithermal environment

Sánchez-Alfaro

Reich

Driesner

et al. 2016

Ore Geology Reviews

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Epithermal gold (Au) deposits result from the combination of a sustained flux of metalrich fluids and an efficient precipitation mechanism. Earthquakes may trigger gold precipitation A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTby rapid loss of fluid pressure but their efficiency and time-integrated contribution to gold endowment are poorly constrained. In order to quantify the feedbacks between earthquake-driven fracturing and gold precipitation in the shallow crust, we studied the gold-rich fluids in the active Tolhuaca geothermal system, located in the highly seismic Southern Andes of Chile. We conditions -may significantly enhance gold precipitation rates in the shallow crust and lead to overall increases in metal endowment over time.

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Section: Gold Solubility Calculations In Pressure-enthalpy Spacementioning

confidence: 99%

The optimal windows for seismically-enhanced gold precipitation in the epithermal environment

Sánchez-Alfaro

Reich

Driesner

et al. 2016

Ore Geology Reviews

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“…The creation and compilation of thermodynamic databases, along with improved computer technology, laid the basis for this development. The databases have been used with geochemical computer codes, such as EQ3/6 (Wolery, 1983(Wolery, , 1992, WATCH (Arnórsson et al, 1982;Bjarnason, 1994), SUPCRT92 (Johnson et al, 1992), PHREEQC (Parkhurst et al, 1980;Parkhurst and Appelo, 1999) and TOUGHREACT (Xu et al, 2006(Xu et al, , 2011, allowing for rapid simulations of mineral solubility and solute speciation in a variety of geochemical systems. The codes differ in complexity and ease of use, but all accurately solve for the equilibrium assemblages of minerals and aqueous species, and mineral solubilities within the limits of their thermodynamic databases.…”

Section: Introductionmentioning

confidence: 99%

Development and evaluation of a thermodynamic dataset for phases of interest in CO2 mineral sequestration in basaltic rocks

2012

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Keywords: Thermodynamic dataset CO 2 -waterbasalt interaction Geochemical modeling CO 2 geological storage In situ CO 2 mineral sequestration A B S T R A C T A thermodynamic dataset describing 36 mineral reactions of interest for CO 2 -water-basalt interaction associated with CO 2 mineral sequestration in basaltic formations is presented. Mineral selection for the dataset is based on extensive review of natural analogs of water-basalt interaction at low and elevated CO 2 conditions. Widely used thermodynamic databases did not contain the mineral assemblage needed for successfully simulating the alteration processes observed in nature as important primary and secondary minerals were found to be missing. The EQ3/6 V7.2b database is the primary source for aqueous equilibrium constants in the developed dataset but reactions for four missing Al-hydroxy complexes were added. Recently published thermodynamic data were compiled for most of the minerals considered in this study. Mineral solubility constants obtained directly from measurements were compiled to the dataset without modification but SUPCRT was used for computing solubility constants when such data was not available. In order to verify that the presented dataset can capture alterations observed in nature, simulations of CO 2 -water-basalt interaction were carried out at low and elevated CO 2 conditions and compared to observed basalt alteration in Iceland and Greenland. Overall simulated and observed alteration are in good agreement, both at low and elevated CO 2 conditions, suggesting the dataset to be well suited for simulations of e.g. CO 2 -water-basalt interaction associated with CO 2 mineral sequestration in basalts.

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“…The AuCl 2 -contour is from Murray and Cubiciotti (1983). The kaolinite -sericite and sericiteadularia boundaries are from Arnorsson et al (1982Arnorsson et al ( , 1983. Other data sets are quoted from Barton (1984 …”

Section: Depth Of Mineralizationmentioning

confidence: 99%

Hydrothermal Gold Mineralization at the Rodnikovoe Deposit in South Kamchatka, Russia

Takahashi¹,

Matsueda

Okrugin

2002

Resource Geology

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Abstract:The Rodnikovoe gold deposit situated in a presently active hydrothermal system located north of the MutnovskoAsachinskaya geothermal area in southern Kamchatka, Far Eastern Russia, consists of typical low-sulfidation quartz-adularia veins in a host rock of diorite. The age of the mineralization was dated by the K-Ar method as 0.9 to 1.1 Ma based on adularia collected from the veins. Representative ore minerals in the deposit are electrum, argentite, aguilarite, polybasite, pearceite and lenaite. Dominant alteration minerals are adularia, α-cristobalite, chlorite, illite and kaolinite. Hydrothermal solutions of neutral pH were responsible for the mineralization, which is divided into six stages defined by tectonic boundaries. Gold mineralization occurred in stages I and III. Hydrothermal brecciation occurred during stages III, IV and VI. Stages II, IV, V and VI were barren. The estimated ore formation temperature based on a fluid inclusion study is 150 to 250 ˚C at a depth of approximately 170 m below the paleo-water table. Boiling of hydrothermal fluids is hypothesized as the cause of the intermittent deposition of gold ore. The sulfur and oxygen fugacities during the deposition of anhydrite prior to the hydrothermal brecciation were higher than those during the gold mineralization stages. The occurrence in the hydrothermal breccia of fragments of high grade Au-Ag and polymetallic ores suggests that higher grade mineralization of these metal ores might have occurred in a deeper portion of the deposit.

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The chemistry of geothermal waters in Iceland. I. Calculation of aqueous speciation from 0° to 370°C

Cited by 235 publications

References 34 publications

The optimal windows for seismically-enhanced gold precipitation in the epithermal environment

The optimal windows for seismically-enhanced gold precipitation in the epithermal environment

Development and evaluation of a thermodynamic dataset for phases of interest in CO2 mineral sequestration in basaltic rocks

Hydrothermal Gold Mineralization at the Rodnikovoe Deposit in South Kamchatka, Russia

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