Geysir Group Publications

2015

Kaasalainen, H., Stefánsson, A., Giroud, N., Arnórsson, S. (2015) The geochemistry of trace elements in geothermal fluids, Iceland. Applied Geochemistry 62, 207-223, http://dx.doi.org/10.1016/j.apgeochem.2015.02.003.

Stefánsson, A., Gunnarsson, I., Kaasalainen, H., Arnórsson, S. (2015) Chromium geochemistry and speciation in natural waters, Iceland. Applied Geochemistry 62, 200-206, http://dx.doi.org/10.1016/j.apgeochem.2014.07.007.

Geilert S., Vroon P.Z., Keller N.S., Gudbrandsson S., Stefánsson A. and van Bergen M.J. (2015): Silicon isotope fractionation during silica precipitation from hot-spring waters: Evidence from the Geysir geothermal field, Iceland. Geochimica et Cosmochimica Acta 164 (403-427), doi: 10.1016/j.gca.2015.05.043.


Gislason S.R., Stefánsdóttir G., Pfeffer M.A., Barsotti S., Jóhannsson Th., Galeczka I., Bali E., Sigmarsson O, Stefánsson A., Keller N.S., Sigurdsson Á., Bergsson B., Galle B., Jacobo V.C., Arellano S., Aiuppa A., Jónasdóttir E.B., Eiríksdóttir E.S., Jakobsson S., Gudfinnsson G.H., Halldórsson S.A., Gunnarsson H., Haddadi B., Jónsdóttir I., Thordarson Th., Riishus M., Högnadóttir Th., Dürig T., Pedersen G.M., Höskuldsson Á. and Gudmundsson M.T. (2015): Environmental pressure from the 2014-15 eruption at Bárðarbunga volcano, Iceland. Geochemical Perspectives Letters 1 (84-93), doi: 10.7185/geochemlet.1509


Stefánsson A., Keller N.S., Gunnarsson Robin J. and Ono S. (2015): Multiple sulfur isotope systematics of Icelandic geothermal fluids and the source and reactions of sulfur in volcanic geothermal systems at divergent plate boundaries. Geochimica et Cosmochimica Acta 165, 307-323, doi: 10.1016/j.gca.2015.05.045


 Prathap Moola, Bergur Sigfússon, Andri Stefánsson. (2015): Geochemical behavior of some common hydrological tracers. Poster, talk and abstract at the European PhD day, Delft, Holland, February 2015.


Přikryl J. & Stefánsson A. (2015): CO2 mineralization by olivine at hydrothermal conditions. Min. Mag. Online ISSN: 1471-8022

2014

 Prathap Moola, Andri Stefánsson, Bergur Sigfússon. (2014): Evaluation of common hydrological tracers in porous media. Abstract and talk at science day Reykjavik Energy, Iceland, March 2014.


 Prathap Moola, Andri Stefánsson, Bergur Sigfússon. (2014): Pore-volume alteration measurements to evaluate scale formation during solid-fluid interactions. Mineralogical Magazine 78, 1399-1403.


 Snorri Guðbrandsson, Prathap Moola, Andri Stefánsson. (2014): H2S injection into basaltic formation,SulFix. The international carbon conference, Reykjavik, Iceland, August 2014.


 Prathap Moola, Andri Stefánsson, Bergur Sigfússon. (2014): Evaluation of common hydrological tracers in porous rocks through flow through column experiments. The international carbon conference,Reykjavik, Iceland, August 2014.


Heřmanská M, Stefánsson, A (2014) Multicomponent fluid chemistry within multiphase system around cooling plutons with relation to the Krafla geothermal system, NE Iceland. The international Carbon Conference, Reykjavik, August 2014 (abstract).


Heřmanská M, Stefánsson, A (2014)  Geochemistry of Multicomponent Fluid Phases in the Krafla High-Enthalpy Geothermal System, NE Iceland. AGU fall meeting, December 2014. (abstract)


Keller N.S., Stefánsson A. and Sigfússon B:  Determination of Arsenic Speciation in Sulfidic Waters by Ion Chromatography Hydride-Generation Atomic Fluorescence Spectrometry (IC-HG-AFS)Talanta 128, 466-472, doi: 10.1016/j.talanta.2014.04.035


Keller N.S., Stefánsson A. and Sigfússon B:  Arsenic speciation in natural sulfidic geothermal waters. Geochim. Cosmochim. Acta 142, 15-26, doi: 10.1016/j.gca.2014.08.007


Přikryl J. & Stefánsson A. (2014): Reaction progress of olivine alteration as a function of time and CO2 supply at 150°C – An Experimental Study. AGU Fall meeting – Abstract Volume.


Přikryl J. & Stefánsson A. (2014): The effects of time and acid supply on olivine alteration – an experimental study. The International Carbon Conference – Abstract Volume. p. 70.


Stefánsson, A., Kaasalainen, H., Keller, N.S., Gunnarssson, I., Sigfússon, B. 2014. Disequilibrium aqueous speciation and chemical energy in hydrothermal systems. Surtsey at 50 years – 2014 ICDP workshop, Vestman Islands, Iceland, September-October 2014.


Kaasalainen, H., Stefánsson, A. 2014. Iron chemistry and speciation in geothermal waters, Iceland. International Carbon Conference, Reykjavík, Iceland, August 2014.

2013

Kaasalainen, H., Stefánsson A.  (2013) Sulfur chemistry in geothermal fluids, Iceland. GSA Abstracts with Programs 45, No. 7.


Kaasalainen, H., Stefánsson A.  (2013) The chemistry of trace elements in geothermal waters, Iceland. GSA Abstracts with Programs 45, No. 7.


Stefánsson A., Keller N.S. and Sigfússon B. (2013) Arsenic speciation in sulfidic geothermal waters. GSA Abstract 45


Stefánsson A., Gunnarsson I., Kaasalainen H. and Arnórsson S. (2013) Chromium chemistry and speciation in natural waters associated with mafic rocks, Iceland. GSA Abstract 45


Keller N.S., Stefánsson A., Ono S. and Gunnarsson Robin J. (2013) Sulfur isotope systematics of geothermal fluids, Krafla, Iceland. Min. Mag. 77, 1445.


Moola P., Sigfússon B. and Stefánsson A. (2013) Reactive transport of common hydrological tracers in porous media – an experimental study. Min. Mag. 77, 1789.


Přikryl J., Stefánsson A. and Sigfússon B. (2013) CO2-olivine interaction in porous media - an experimental study. Min. Mag. 77, 1998.


Stefánsson A., Lemke K., Bénézeth P. and Schott J. (2013) IR specroscopic and quantum chemical study of metal bicarbonate and carbonate intreaction in aqeuous solutions. Min. Mag. 77, 2256.


Stefánsson A., Driesner T. and Bénézeth P (2013) Thermodynamics of Geothermal Fluids. Rev, Min. Geochem. 76, 1-4.


Stefánsson A., Bénézeth P. and Schott J. (2013) Carbonic acid ionization and the stability of sodium bicarbonate and carbonate ion pairs to 200 °C – A potentiometric and spectrophotometric study. Geochim. Cosmochim. Acta 120, 600-611.


Kaasalainen H., Stefánsson A., Gunnarsson I. and Arnórsson S. (2013) Chromium chemistry in natural waters, Iceland. Mineralogical Magazine 77, 1414.


Galeczka I., Wolff-Boenisch D., Jonsson T., Sigfússon B. and Stefánsson A. (2013) A novel high pressure column flow reactor for experimental studies of CO2 mineral storage. Appl. Geochem. 30, 91-104.

2012

Borisova A.Y., Toutain J-P., Stefansson A, Gouy S, Parseval P. (2012) Processes controlling the 2010 Eyjafjallajokull explosive eruption. J. Geophys. Res. Solid Earth 117, B05202.


Gysi A.P., Stefánsson A. (2012) CO2-water-basalt interaction. Low temperature experiments and implications for CO2 sequestration into basalts. Geochim. Cosmochim. Acta 81, 129-152.


Gysi A.P., Stefánsson A. (2012) Experiments and geochemical modeling of CO2 sequestration during hydrothermal basalt alteration. Chem. Geol. 306, 10-28.  


Gysi A.P., Stefánsson A. (2012) Mineralogical aspects of CO2 sequestration during hydrothermal basalt alteration - An experimental study at 75 to 250 °C and elevated pCO2. Chem. Geol. 306, 146-159.


Kaasalainen, H., Stefansson, A. (2012) The chemistry of trace elements in surface geothermal waters and steam, Iceland. Chem. Geol. 330, 60-85.


Marteinsson V.T., Rúnarsson Á., Stefánsson A., Thorsteinsson T., Jóhannesson T., Magnússon S.H., Reynisson E., Einarsson B., Wade N., Morrison H.G. and Gaidos E. (2012) Microbial communities in the subglacial waters of the Vatnajökull ice cap, Iceland. The ISME Journal 7, 427-437.

2011

Alfredsson, H.A., Wolff-Boenisch, D., Stefánsson, A. (2011)  CO2 sequestration in basaltic rocks in Iceland: Development of a piston-type downhole sampler for CO2 rich fluids and tracers. Energy Procedia 4, 3510-3517.


Borisova A.Y., Portnyagin M., Toutain J.P., Stefansson A., Gouy S., Parseval P. (2011) Processes Triggering Explosive Eruption of Mantle Plume-Derived Magma. AGU 2011 fall meeting, V33D-2675.


Gunnarsson, I., Sigfússon, B., Stefánsson, A., Arnórsson, S.,  Scott, S.M., Gunnlaugsson, E. (2011) Injection of H2S from Hellisheiði power plant, Iceland. 36th Stanford GeothermalWorkshop, 


Gysi A., Stefánsson A. (2011) CO2 Sequestration and Hydrothermal Basalt Alteration at 40-250°C. Goldschmidt 2011, 961


Gysi A., Stefánsson A. (2011) CO2 Sequestration and Hydrothermal Basalt Alteration at 40-250°C. Goldschmidt 2011, 961


Gysi, A.P., Stefánsson, A. (2011) CO2-water-basalt interaction. Numerical simulation of low temperature CO2 sequestration into basalts. Geochim. Cosmochim. Acta 75, 4728-4751.


Kaasalainen, H., Stefansson, A. (2011) Chemical analysis of sulfur species in geothermal waters. Talanta 85, 1897-1903 


Kaasalainen, H., Stefánsson, A. (2011) Sulphur and metal transport in active geothermal systems, Iceland. EGPD 2011, Reykjavik, Iceland.


Kaasalainen, H., Stefánsson, A. (2011) Sulphur and metal transport in active geothermal systems, Iceland – surface geothermal environments. Icelandic Geological Soc. Spring meeting 2011, 30-31.


Kaasalainen, H., Stefánsson, A. (2011) Sulphur speciation at redox disequilibrium in natural geothermal waters,Iceland. Icelandic Geological Soc. Spring meeting 2011, 28-29.


Kaasalainen, H., Stefánsson, A. (2011) Sulfur speciation in natural hydrothermal waters, Iceland. Geochim. Cosmochim. Acta 75, 2777-2791.


Keller N.S., Stefánsson A., Kaasalainen H., Sigfússon B. (2011) Volatile Transport and Reactions in Geothermal Systems: Arsenic and Sulfur in Icelandic Hot Springs and Wells. ICGG 11, 75-76


Keller N.S., Stefansson A., Sigfusson B. (2011) Arsenic Speciation in Geothermal Waters. AGU 2011 fall meeting, V13D-2639.


Keller N.S., Stefánsson A., Sigfússon B. (2011) Arsenic Speciation in Geothermal Waters. Icelandic Geological Soc. Spring meeting 2011, 47-48.


Markússon, S.H., Stefánsson, A. (2011) Hydrothermal surface alteration of basalts, Krýsuvík Iceland – alteration mineralogy, water chemistry and the effects of acid supply on the alteration process. J.Volcanol. Geotherm. Res. 206, 46-59.  


Matter J.M., W.S. Broecker, S.R. Gislason, E. Gunnlaugsson, E.H. Oelkers, M. Stute, H. Sigurdardóttir, A. Stefansson, H.A. Alfreðsson, E.S. Aradóttir, G. Axelsson, B. Sigfússon, D. Wolff-Boenisch (2011) The CarbFix Pilot Project–Storing carbon dioxide in basalt. Energy Procedia 4, 5579-5585. 


Padilla K., Stefánsson A., Fridriksson Th. (2011) Transport and precipitation of carbon and sulphur in the Reykjanes geothermal system, Iceland.. EGPD 2011, Reykjavik, Iceland.


Portnyagin M., Borisova A.Y., Plechov P., Shkurski B., Stefansson A. (2011) Magma mixing during the 2010 Eyjafjallajökull eruption. AGU 2011 fall meeting, V33D-2676.


Rodríguez A., Stefánsson A. (2011) Water-rock interaction of silicic rocks under geothermal conditions: An experimental and modelling study. EGPD 2011, Reykjavik, Iceland.


Scott S., Gunnarsson I., Stefánsson A., Arnórsson S., Gunnlaugsson E. (2011) Gas Chemistry of the Hellisheiði Geothermal Field. EGPD 2011, Reykjavik, Iceland.


Scott, S., Gunnarsson, I., Stefánsson, A., Gunnlaugsson, E. (2011) Gas chemistry of the Hellisheidi geothermal field, SW-Iceland. 36th Stanford GeothermalWorkshop,   


Sigurðardóttir A.S., Stefánsson A., Hreggviðsson G.O., Björnsdóttir S., Pétursdóttir S. (2011) Quantification of geochemical energy in geothermal ecosystems. Icelandic Geological Soc. Spring meeting 2011, 4-5.


Sigurðardóttir A.S., Stefánsson A., Hreggviðsson G.O., Björnsdóttir S., Pétursdóttir S. (2011) Quantification of geochemical energy in geothermal ecosystems. EGPD 2011, Reykjavik, Iceland.


Stefansson A., Bénézeth P., Lemke K. (2011) An experimental and theoretical study on the ion pair formation and mineral solubility in the system Mg+CO2+H2O. AGU 2011 fall meeting, GC51B-0955.


Stefánsson A., Kaasalainen H., Lemke K., Prapaipong P., Shock W. (2011) Metal speciation and transport by geothermal and volcanic vapor. ICGG 11, 104-105.


Stefansson A., Lemke K., Benezeth P., Schott J. (2011) The Stability and Structure of Mg2+ Bicarbonate and Carbonate Ion Pairs – An Experimental and Theoretical Study. Goldschmidt 2011, 1934.


Stefánsson, A., Arnórsson, S., Gunnarsson, I., Kaasalainen, H., Gunnlaugsson, E. (2011) The geochemistry and sequestration of H2S into geothermal system at Hellisheidi, Iceland. J.Volcanol. Geotherm. Res. 202, 179-188.

2010

Arnórsson S., Angcoy E., Bjarnason J.Ö., Giroud N., Gunnarsson I., Kaasalainen H., Karingithi C., Stefánsson A. (2010) Gas Chemistry of Volcanic Geothermal Systems. Proceedings World Geothermal Congress 2010,  Bali, Indonesia 25-29 April 2010.


Gíslason, S.R., Wolff-Boenisch, D., Stefánsson, A., Alfredsson, H., Oelkers, E.H., Gunnlaugsson, E., Sigurdardóttir, H., Sigfússon, B., Aradóttir, E.S.P., Broecker, W.S., Matter, J.M., Stute, M., Axelsson, G. (2010) Mineral sequestration of CO2 in basalt – the CarFix project. Goldschmidt 2010, Geochim. Cosmochim. Acta A336.


Gislason, S.R., Wolff-Boenisch, D., Stefansson, A., Oelkers, E.H., Gunnlaugsson, E.,  Sigurdardottir, H., Sigfusson, B.,  Broecker, W.S., Matter, J.M., Stute, M.,  Axelsson, G. (2010) Mineral seqestration of CO2 -  The CarbFix project. EGU 2010.


Gíslason, S.R., Wolff-Boenisch, D., Stefansson, A., Oelkers, E.H., Gunnlaugsson, E.,  Sigurdardottir, H., Sigfusson, B., Broecker, W.S., Matter, J.M., Stute, M., Axelsson, G., Fridriksson, Th. (2010) Mineral sequestration of carbon dioxide in basalt: A pre-injection overview of the CarbFix project. Int. J. Green. Gas. Control. 4, 537-545.


Kaasalainen, H.,Stefánsson, A. (2010). Metal and sulfur transport by geothermal fluids, Iceland. Vonthing – Engineering and Natural Sciences Research symposium, University of Iceland.


Kaasalainen, H., Stefánsson, A. (2010) Sulfur speciation in natural geothermal fluids, Iceland – Kinetically or thermodynamically controlled?  Geochim. Cosmochim. Acta 74(12), Supplement 1, A487. Goldschmidt conference, Knoxville, Tennessee, June 2010.


Stefánsson, A. (2010) Low-temperature alteration of basalts – the effects of temperature, acids and time on mineralization and water chemistry. Jökull 60, 165-184.


Stefánsson, A., Arnórsson, S., Gunnarsson, I., Gysi, A.P., Kaasalainen, H., Gunnlaugsson, E. (2010) H2S and CO2 sequestration in geothermal systems. Geochim. Cosmochim. Acta 74, Suppl.1., A991. Goldschmidt conference, Knoxville, Tennessee, June 2010.


Stefánsson, S., Fridriksson, Th., Markússon, S.H., Björke, J.K. (2010) Geothermal water, alteration and precipitates at the surface of high-temperature geothermal systems. Sci. Ins. Report RH-01-2010.

2009

Bjorke JK, Stefansson A, Fridriksson T (2009) Fluid geochemistry and surface alteration associated with rhyolitic rocks, Torfajokull Iceland. Geochim.Cosmochim. Acta 73, A127


Gaidos E., Marteinsson V., Thorsteinsson Th., Johannesson T., Runarsson A.R., Stefansson A., Glazer B., Lanoil B., Skidmore M., Han S.,  Miller M., Rusch A.,  Foo W. (2009) An oligarchic microbial assemblage in the anoxic bottom waters of a volcanic subglacial lake. ISEM J. 2009, 1-12.


Gislason S.R., Broecker W.S., Oelkers E.H., Gunnlaugsson E., Sigurdardottir H., Stefansson A., Wolff-Boenisch D., Matter ., Stute M., Axelsson G. (2009) The Carbfix project: Mineral CO2 sequestration into basalt. Geochim.Cosmochim. Acta 73, A440.


Gysi AP, Stefansson A. (2009) CO2-water-basalt interaction: Geochemical modelling and experiments. Geochim.Cosmochim. Acta 73, A483. 


Gysi, A., Stefansson, S. (2009) Low temperature CO2 mineralization into basalt: solution chemistry and secondary mineral assemblages. Eos Trans. AGU 90.


Kaasalainen, H., Stefansson, A., Giroud, N., Arnórsson, S. (2009) Metal transport by geothermal and volcanic vapour. Geochim.Cosmochim. Acta 73 Supplement, A610. Goldschmidt Conference, Davos, Switzerland, July 2009.


Kaasalainen, H., Stefánsson, A., Prapaipong, P., Giroud. N., Arnórsson, S., Shock, E. (2009) Metal transport by geothermal and volcanic vapor. Eos Trans. AGU 90(52), Fall meeting Suppl., abstract V51G-04.


Markusson SH, Stefansson A, Fridriksson T (2009) Acid sulfate alteration of basalts in active geothermal systems, Krisuvik, Iceland.  Geochim.Cosmochim. Acta 73, A835. 


Matter, J.M., Broecker, W.S. , Stute, M. , Gislason, S.R. , Oelkers, E.H. , Stefánsson, A., Wolff-Boenisch, D., Gunnlaugsson, E., Axelsson, G., Björnsson, G. (2009) Permanent Carbon Dioxide Storage into Basalt: The CarbFix Pilot Project, Iceland. Energy Procedia 1, 3641-3646.


Stefansson A. (2009) Thermodynamics of natural geothermal systems. Geochim.Cosmochim. Acta 73, A1266.


Stefánsson, A., Arnórsson, S., Gunnarsson, I. Kaasalainen, H. 2009. Förgun brennisteins frá Hellisheiðarvirkjun Jarðefnafræðileg athugun. Orkuveita Reykjavikur. RH-14-2009. (Report in Icelandic).


Stefansson, S., Arnórsson, S., Gunnarsson, I., Kaasalainen, H.S. (2009) H2S sequestration from Hellisheidi Power Plant – a geochemical investigation. Sci. Inst. Report, RH-14-2009.


Wolff-Boenisch, D., Gislason, S.R., Oelkers, E.H., Broecker, W.S., Matter, J.M., Stute, M., Stefansson, A., Gunnlaugsson, E., Björnsson, G., Axelsson, G. (2009) In-situ carbonatization of CO2 - The Carbfix project in Iceland. EGU 2009.

2008

Gíslason, S.R., Broecker, W.S., Oelkers, E.H., Gunnlaugsson, E., Stefansson, A., Wolf-Boenisch, D., Matter, J., Björnsson, G. (2008) Mineral CO2 sequestration into basalt: the Carbfix project. Eos Trans. AGU 89.


Gysi A.P. and Stefánsson, A. (2008) Numerical modelling of CO2-water-basalt interaction. Mineralogical Magazine 72, 55-59.


Gysi P.G. and Stefánsson A. (2008) Numerical modeling of CO2-water-basalt interaction. SSC/MT 11.


Kaasalainen, H., Stefansson, A. (2008) Metal geochemistry in surface geothermal waters in Iceland. IAVCEI General Assembly, Reykjavik, Iceland, August 2008.


Kaasalainen, H., Stefansson, A. (2008) The chemistry of sulfur in volcanic geothermal fluids. Geochim. Cosmochim. Acta 72(12) Supplement, A443.


Kaasalainen, H., Stefansson, A. (2008) Geochemistry of surface geothermal waters at Krafla and Námafjall. Science Symposium, University of Iceland, March, 2008.


Stefánsson A. (2008) CO2-basalt interaction. Disko-Nuussuaq, West-Greenland analogue. SSC/MT, 12.


Stefansson A. (2008) Numerical simulation of CO2-water-basalt interaction. . Institute of Earth Sciences Report, RH-2-2008.


Stefansson A. and Gysi A.P. (2008) CO2-basalt interaction - Numerical simulation and experimental study. Geochim. Cosmochim. Acta 72, A894.


Stefansson A. and Kaasalainen H. (2008) Sulfur speciation in geothermal waters, Iceland. IAVCEI 2008.


Stefansson A., Lemke K. and Seward T.M. (2008) Iron(III) complexation in hydrothermal solutions – an experimental and theoretical study. ICPWS XV, Geo 05


Stefansson A.,Thorsteinsson Th., Jóhannesson T., Einarsson B., Gaidos E.J. and Marteinsson V. (2008)  Circulation, chemistry, thermodynamics and biology of the Skaftárkatlar subglacial geothermal lakes, Vatnajökull ice cap, Iceland. IAVCEI 2008.


Stefánsson, A. and Seward T.M. (2008) The hydrolysis of iron(III) in hydrothermal solutions. Chemical  Geology 249, 227-245.


Thorsteinsson T., Elefsen S.O., Gaidos E., Lanoil B., Johannesson T., Kjartansson V., Marteinsson V.P., Stefansson A., Thorsteinsson T. (2008) A hot water drill with built-in sterilization: design, testing and performance. Jökull 57, 71-82.


Tobler D., Stefansson A., Benning L.G. (2008) In-situ silica sinters in Icelandic geothermal areas. Geobiology 6, 481-502.

2007

Di Figlia, M.G., Bellanca, A., Rodolfo, N. and Stefánsson, A., (2007) Chemical weathering on volcanics of Pantelleria Island, Sicily. Chemical Geology 246, 1-18. 


Johannesson T, Thorsteinsson T., Stefansson A., Gaidos E.J., Einarsson, B. (2007) Circulation and thermodynamics in a subglacial geothermal lake under the Western Skafta cauldron of the Vatnajokull ice cap, Iceland. Geophys. Res. Lett. 34, L19502. 


Arnórsson S., Stefánsson A., and Bjarnason J.Ö. (2007) Fluid-Fluid Interactions in Geothermal Systems. Rev. Mineral. Geochem. 65, 259-312.


Stefánsson, A. (2007) Iron(III) hydrolysis and solubility at 25°C. Env. Sci. Technol., 41, 6117–6123.


Gaidos E., Glazer B., Harris D., Heshiki Z., Jeppsson N., Miller M., Thorsteinsson T., Einarsson B., Kjartansson V., Stefansson A., Johannesson T., Roberts M., Skidmore M., Lanoil B. (2007) A simple sampler for subglacial water bodies.  J. Glaciol. 53, 157-158. 


Stefánsson A., Gunnarsson I and Giroud N. (2007) New methods for the direct determination of dissolved inorganic, organic and total carbon in natural waters by Reagent-Free™ Ion Chromatography and Inductively Coupled Plasma Atomic Emission Spectrometry. Anal. Chim. Acta 582, 69-74.


Stefansson A. and Fridriksson T. (2007) Solubility of Hellisheidi geothermal gas in water. Institute of Earth Sciences Report, RH-16-2007.


Markusson, S.H., Stefansson, A., Gunnarsson, I. (2007) Sulfur speciation and metal transport in surface geothermal waters. Geochim. Cosmochim. Acta 71, A624.


Stefansson A., Seward T.M., Gunnarsson I. (2007) The hydrolysis and cloro complexation of iron(III) in hydrothermal solutions. Geochim. Cosmochim. Acta 71, A969.

2006

Arnórsson S., Bjarnason J.Ö., Giroud N., Gunnarsson I., and Stefánsson A. (2006) Sampling and analysis of geothermal fluids. Geofluids 6, 203-216.


Stefánsson, A. (2006) Results of spectrophotometric measurements in the system Fe(ClO4)3+ HClO4+H2O to 200°C and Fe3+ hydrolysis. . Institute of Earth Sciences Report, RH-22-2006


Stefánsson, A. (2006) Iron(III) hydrolysis and solubility at 25°C. Results of potentiometric, spectrophotometric and solubility measurements. . Institute of Earth Sciences Report, RH-24-2006.


Stefánsson, A. (2006) Results of spectrophotometric measurements in the system Fe(III)+HCl+NaCl+HClO4+H2O to 200°C and stability of iron(III) chloride complexes. . Institute of Earth Sciences Report , RH-23-2006.


Andri Stefánsson, Ingvi Gunnarsson , Anton Carrasco, Axel B. Kleindienst, Elisabeth Neubauer, Felix W. Von Aulock, Ingi Þ. H. Kúld, Joseph O. Ajayi, Kizito M. Opondo, Kristinn L. Guðmundsson, Sonja Theissen, Steinþór Níelsson, Stephanie A. Hahnewald, Ursina Liebke (2006) Geothermal waters in Geysir area - Mixing, boiling, water-rock interaction and conceptual model. Spring meeting of the Icelandic Geological Soc.


Ingvi Gunnarsson, Andri Stefánsson, Níels Óskarsson, Anton Carrasco, Axel B. Kleindienst, Elisabeth Neubauer, Felix W. Von Aulock, Ingi Þ. H. Kúld, Joseph O. Ajayi, Kizito M. Opondo, Kristinn L. Guðmundsson, Sonja Theissen, Steinþór Níelsson, Stephanie A. Hahnewald, Ursina Liebke (2006) Acid geothermal waters and elemental mobility at Krísuvík. Spring meeting of the Icelandic Geological Soc.

2005

Arnórsson, S. and Stefánsson, A. (2005) Wet-steam well discharges. II. Assessment of aquifer fluid compositions. World Geothermal Congress.

2004

Stefánsson, A., and Seward, T.M. (2004) Gold(I) complexing in aqueous sulphide solutions to 500°C at 500 bar. Geochimica et Cosmochimica Acta 68, 4121-4143.

2003

Stefánsson, A., and Seward, T.M. (2003) Experimental determination of the stability and stoichiometry of sulphide complexes of silver(I) in hydrothermal solutions to 400°C at 500 bar. Geochimica et Cosmochimica Acta 67, 1395-1413.


Stefánsson, A., and Seward, T.M. (2003) The stability of chloridogold(I) complexes in hydrothermal solutions to 600°C and 1800 bar. Geochimica et Cosmochimica Acta 67, 4559-4576.

2002

Arnórsson, S., Gunnarsson, I., Stefánsson, A., Andrésdóttir, A., and Sveinbjörnsdóttir, Á.E. (2002) Major element chemistry of surface- and ground waters in basaltic terrain, N-Iceland. I. Primary mineral saturation. Geochimica et Cosmochimica Acta 66, 4015-4046.


Stefánsson A. and Arnórsson, S. (2002). Gas pressures and redox reactions in geothermal systems in Iceland. Chemical Geology 190, 251-271.


Arnórsson, S., Stefánsson, A., and Gunnarsson, I. (2002) Primary basalt mineral saturation in surface- and up to 90°C ground waters in Skagafjördur, N-Iceland. Annual Meeting of the Icelandic Geoscience Society, Oct. 2002.


Arnórsson, S., and Stefánsson, A. (2002) Assessment of scaling potential from supercritical geothermal fluids. IDDP/ICDP Workshop Oct. 2002.


Stefánsson, A. and Seward, T.M. (2002) The hydrolysis of gold(I) and the formation of chlorogold(I) complexes in hydrothermal solutions to 600°C and 2 kbar. Goldschmidt conference 2002. Geochimica et Cosmochimica Acta 64A, 737.


Stefánsson, A. and Seward, T.M. (2002) An experimental study on silver transport in hydrothermal solutions. EMPG IX, Journal of Conference Abstracts.

2001

Stefánsson, A. (2001) Dissolution of primary minerals of basalt in natural waters I. Calculation of mineral solubilities from 0ºC to 350ºC. Chemical Geology 172, 225-250.


Stefánsson, A., Gíslason, S.R., and Arnórsson, S. (2001) Dissolution of primary minerals of basalt in natural waters II. Mineral saturation state. Chemical Geology 172, 251-276.


Stefánsson, A. and Gíslason, S.R. (2001) Chemical weathering of basalts, SW Iceland.  Effect of rock crystallinity, weathering minerals and vegetative cover on chemical fluxes to the ocean. American Journal of Science 301, 513-556.


Gíslason, S.R., Oelkers E.H., and Stefánsson, A. (2001) Controls  on  chemical weathering of basalt. Goldschmidt 2001, Journal of Conference Abstracts.

2000

Stefánsson A. and Arnórsson, S. (2000) Saturation state of feldspars in natural waters. Geochimica et Cosmochimica Acta 64, 2567-2584.


Stefánsson, A. and Seward, T.M. (2000) New experimental data on gold transport in hydrothermal solutions. Séminaire de métallogénie du 24 janvier 2000 qui se tiendra à la Section des Sciences de la Terre de l'Université de Genève.


Stefánsson, A. and Seward, T.M. (2000) New experimental data on gold transport in hydrothermal solutions. Séminaire de métallogénie du 24 janvier 2000 qui se tiendra à la Section des Sciences de la Terre de l'Université de Genève.


Stefánsson, A. and Seward, T.M. (2000) Gold(I) complexing by sulphide ligands in hydrothermal solutions to 450 ºC at 500 bar. Goldschmidt 2000, Journal of Conference Abstracts 5, 953.


Arnórsson, S. and Stefánsson, A. (2000) Mineral-solution equilibria in groundwater systems. Goldschmidt 2000, Journal of Conference Abstracts 5, 155-156.


Stefánsson, A. and Seward, T.M. (2000) Gold(I) sulphide complexing in hydrothermal solutions. Geochemistry of crustal fluids. EURESCO conference, Granada, Spain, 2-7.12.2000, 95.

1999

Arnórsson, S. and Stefánsson, A. (1999) Assessment of feldspar solubility constants in water in the range 0º to 350ºC at vapor saturation pressure. American Journal of Science 299, 173-209.


Stefánsson, A. and Arnórsson, S. (1999) Feldspar equilibria in geothermal waters. In Proceedings of the 5th international symposium on geochemistry of the Earth’s surfaces, Balkema Press, 543-546.


Egilson, S., Ólafsdóttir, E.D., Yngvadóttir, E., Halldórsdóttir, H., Sigurdsson, F.H., Jónsson, G.S., Jensson, H., Gunnarsson, K., Thráinsson, S.A., Stefánsson, A., Indridason, H.D.,  Hjartarson, H., Thorlacius, J., Ólafsdóttir, K., Gíslason S.R., and Svavarsson, J. (1999) Environmental monitoring in Iceland The Environmental and Food agency Iceland, 138 pp.

1998

Gíslason, S.R., Stefánsson, A., and Stefánsdóttir, M.B. (1998) The  chemistry of surface- and soil water at Grundartangi, Iceland. Unpublished report April 1998, 60 pp.


Gíslason, S.R., Stefánsson, A., and Stefánsdóttir, M.B. (1998) The  chemistry of surface- and soil water at Grundartangi, Iceland. Unpublished final report July 1998, 84 pp.


Stefánsson, A.,  and Gíslason, S.R. (1998) Chemical denudation rates of a basaltic catchment, SW Iceland.  Mineralogical Magazine 62A, 451-452.


Stefánsson, A., Arnórsson, S., and Gíslason, S.R. (1998) Saturation state of primary basaltic minerals in natural waters.  In Geochemistry of the Crustal Fluids, Characterisation of reactive transport in natural systems, Aghia Pelaghia Greece, 22-27. May 1998, 62.

1997

Gíslason, S.R., Stefánssdóttir M.B., and Stefánsson, A. (1997) The chemistry of surface- and soil water at Grundartangi, Iceland. Unpublished report Nov. 1997, 16 pp.


Arnórsson, S. and Stefánsson, A. (1997) Assessment of feldspar solubility in waters in the range 0-350 ºC at Psat. Science Institute Report, University of Iceland, RH-33-97, 50 pp


Gíslason, S.R., Gunnarsson, I., Stefánsson, A., Stefánssodóttir, M.B., Sveinbjörnsdóttir, Á.E., Kristmannsdóttir, H., Hauksdóttir, S., Snorrason, Á., Zophaníasson, S., Pálsson, S., and Benediktsson, S. (1997) The chemistry of the Grímsvötnum discharge.  Meeting Icel. Geol. Sco. Feb. 1997, 38-40. 


Stefánsson, A. (1997) The geochemistry of aluminium in surface and groundwaters in Laxa in Kjos catchment area, Iceland.  The chemistry of aluminium in surface and ground waters in Iceland. Spring Meeting Icel. Geol. Sco. 1997, 1-3.


Arnórsson, S., Sveinbjörnsdóttir, Á.E., Andrésdóttir, A., Gunnarsson, I., and Stefánsson, A. (1997) Geothermal waters in Skagafirdi: origin and age. Spring Meeting Icel. Geol. Sco. 1997, 44-47.


Arnórsson, S., Andrésdóttir, A., Gunnarsson, I., and Stefánsson, A. (1997) New calibration of the NaK and quartz geothermometers. Spring Meeting Icel. Geol. Sco. 1997, 42-43.

1995

Gíslason, S.R., Andrésdóttir, A., Steingrímsson, J.H., Jósavinsson, R.F., Ásbjörnsson, S., Rúnarsson, Th., Stefánsson, A., Arnardóttir, G., Karlsdóttir, I., and Fridriksson, Th. (1995)  Carbondioxide emission from Eyjafjallajokull, Iceland. Spring Meeting Icel. Geol. Sco. 1995, 24-25

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