CC BY
6
Vol. 7, No. 1, 2021 -
DOI: https://doi.org/10.30525/2256-0742/2021-7-1-1-9
CARBFIX AND SULFIX IN GEOTHERMAL PRODUCTION, AND THE BLUE LAGOON IN ICELAND: GRINDAViK URBAN SETTLEMENT, AND VOLCANIC ACTIVITY
Helga Kristjansdottir1, Sigri'dur Kristjansdottir2
Abstract. This article analyses ways to maintain reservoir sustainability in the area surrounding the Blue Lagoon in Iceland, near the urban settlement of Grindavik on the Reykjanes Peninsula in Iceland. The Svartsengi geothermal power plant operations have pioneered the simultaneous production of electricity and hot water from a geothermal reservoir. The Blue Lagoon is a warm geothermal pool using brine from the power plant. This paper reports on the processes and procedures at the Blue Lagoon and the Svartsengi power station, aimed at increasing sustainability of the geothermal resource by injecting the geothermal brine back to ground, to ensure the geothermal resource sustainability in the area. This paper also discusses and explains in details the reduction of greenhouse gas emissions from geothermal plant operations in Iceland. When the steam from a geothermal reservoir emerges from the ground, it comes up with enough energy to drive turbine generators for electricity production. However, this involves releasing several greenhouse gases into the atmosphere, including hydrogen sulphide (H2S) and carbon dioxide (CO2). This research spotlights a geothermal power plant in HellisheiSi, Iceland, and the use of the CarbFix procedure of capturing and storing carbon dioxide, reducing CO2 emissions from the harnessing of geothermal resources for electricity. CarbFix is a carbon capture and storage (CCS) or carbon mineralization procedure aimed at binding CO2 to rock. This procedure has been used at HellisheiSi power plant for the past decade in Iceland. Scientists have also developed the SulFix procedure, to capture sulphate H2S in ground. These procedures, SulFix and CarbFix, reduce outlet of greenhouse gases by storing them in basalt rock - also referred to as mineral carbonation or carbon capture and storage. This involves dissolving the greenhouse gases in water, and re-injecting them back into the ground through boreholes, in HellisheiSi. This current research also shows the geology in these areas and reports on calculations that have found re-injection of greenhouse gasses to ground to be economically feasible. The paper covers several scenarios that have already been tested to determine the financial feasibility of capture and storage. These have involved calculating the estimated internal rate of return (IRR), the return on investment (ROI) and the present value (NPV). Economic calculations have been made, showing the CarbFix project to be a feasible option contributing to decreased greenhouse gas emissions.
Key words: Greenhouse gas emissions, hydrogen sulphide, SulFix, carbon dioxide, geothermal energy, CO2 fixation, CarbFix, carbon capture and storage, trade, urban planning, volcanic activity.
JEL Classifications: M21, R51, R52
1. Introduction
The Eurasian and North American plate boundaries run through Iceland, with their movement referred to as the continental drift. Recent volcanic activity on the Mid-Atlantic Ridge started 2021, with volcanic eruption and lava flow.
This type of volcanic activity stresses the significant importance of taking threat into account in the infrastructure of the town Grindavík, where
urban settlement initiative is supported by the neighbourhood of rich fishing resources. Also, it reflects on the concerns of having urban settlement in the form of town Grindavík in area, and the Blue Lagoon. Keeping in mind that although knowledge of the geothermal water utilization, this threat of volcanic activity has been considered insignificant. There has not been volcanic activity in this area for about 800 years. Not since around the days of
Corresponding author:
1 Faculty of Business Administration, University of Akureyri, Iceland. E-mail: helga@unak.is
ORCID: https://orcid.org/0000-0002-8857-8063
2 Faculty of Planning and Design, Agricultural University of Iceland, Iceland. E-mail: sigridur@lbhi.is
ORCID: https://orcid.org/0000-0002-8981-8241
Figure 1A. Volcanic Eruption
on the Reykjanes Peninsula starting March 19, 2021
Source: Agust Kristjansson (2021)
the great historian Snorri Sturluson, the author of "Snorra Edda" (Prose Edda) published around 1220, considered the most comprehensive source for modern information of Norse mythology. Geothermal resources from underground reservoirs in the area have beenare harnessed for decades to produce warm water for heating houses and swimming pools, and to
generate electricity (Kristjansdottir, 2015). The focus is also on Iceland's famous Blue Lagoon near the urban settlement of Grindavik, and the geothermal power plant in Svartsengi.
Harnessing geothermal energy in this way also involves the releasing of biogases into the air the CarbFix procedure is employed at HellisheiSi power plant to reduce the environmental impact, also in the geothermal plant in Svartsengi scientists are developing a procedure to clean the gas, separate CO2, and tap on gas containers (potentially for export) for general use of CO2. CarbFix is a carbon capture and storage (CCS) or carbon mineralization procedure aimed at reducing CO2 emissions from the harnessing of geothermal resources for electricity production by binding CO2 to rock (Gislason and Oelkers 2014; RagnheiSardottir et al. 2011). This procedure has been used at HellisheiSi power plant for the past decade in Iceland for the past decade, as well as the SulFix procedure (Gislason et al. 2009; Gislason and Oelkers 2014; RagnheiSardottir et al. 2011).
2. The Blue Lagoon and geothermal energy
The Blue Lagoon in Iceland was created from this brine, as is shown in Figures 2 and 3 (Gislason et al. 2009; Gislason and Oelkers 2014; RagnheiSardottir et al. 2011). Figure 4 shows where the Blue Lagoon is currently situated on the map of Iceland.
The Blue Lagoon was created out of brine of the Svartsengi Geothermal power plant, for the use of bathing. Brine is seawater, heated up in the reservoir. The salt in the reservoir in Svartsengi equals about 2/3 of the salt in the sea. Indicating that the liquid within the reservoir contains about 2/3 sea, and 1/3 fresh water.
Figure 1B. Blue Lagoon, mountain &orbjorn and town Grindavik This the Blue Lagoon setting was operated until 1999, next to the smoking geothermal plant in Svartsengi. The photo is interesting, showing mountain &orbjorn and the fishing town Grindavik behind the mountain, next to sea. Currently, the Blue Lagoon is much further away from the geothermal plant
Source: Lund, 1993
Figure 2. Man standing outside
the Blue Lagoon Iceland. Author's photo (2014)
Figure 3. People bathing in the Blue Lagoon Iceland. Author's photo (2014)
Figure 4. Geothermal Fields in Iceland
Sources: National Energy Authority (2020) and authors' drawings
As the figure shows, the power station is located next to the dormant volcano Eorbjorn; on the other side of mountain Eorbjorn is the urban settlement of the fishing town Grindavik, currently with a population of 3500 people (Statistics Iceland, 2020). Grindavik urban settlement by the Vikings was impacted by the fact how close Grindavik is to the Mid-Atlantic ridge, visible on land on the Reykjanes Peninsula in Iceland. The geothermal project at Svartsengi can be characterized by three stages: the first stage is the prefeasibility stage, which is followed by the construction stage, and finally the operational stage. The harnessing of geothermal energy begins with the identification of an appropriate geothermal reservoir - a natural underground area that can provide warm water or wet steam depending on the reservoir temperature (Gislason et al. 2009; Gislason and Oelkers 2014; RagnheiSardottir et al. 2011). Other factors must be taken into consideration as well, such as the reservoir depth, fluid yield, and drilling conditions.
3. Geology CO2 and H2S storage
In the Hellisheidi mountain area in Iceland, the geothermal plant re-injects carbon dioxide CO2 and hydrogen sulphide H2S (RagnheiSardottir et al., 2011).
When the steam from a geothermal reservoir emerges from the ground, it comes up with enough energy to drive turbine generators for electricity production. However, this involves releasing several greenhouse
Figure 5. Showing map, a of Grindavik town, &orbjorn mountain and Blue Lagoon
Source: National Land Survey of Iceland (2020a). Showing the street pattern of town Grindavík (Kristjansdottir S, 2015b, 2017, 2019b)
Figure 6. Another view of Grindavik, frorbjorn and Blue Lagoon (Goo gle Earth 2020).
The figure exhibits the 3-division figure reflecting on the nature in the lava area on the Reykjanes peninsula
Figure 7. Shows current zoom-in on the Blue Lagoon area, before visible in Figure 6 (Google Earth, 2020). Through use of Google-Earth shows clearly the area where the Svartsengi Geothermal Power Plant is, and the Blue Lagoon.
The power plant constructions, roads and outlet water "outside Blue Lagoon" are also visible
Figure 8. Showing the Blue Lagoon (Blaa LoniS) and mountain frorbjorn, and the street pattern of town Grindavik. Geological Map of Southwest Iceland, 1:100 000 (2nd Ed.). Reykjavik: Iceland GeoSurvey
Source: S&mundsson K., Sigurgeirsson M.A., Hjartarson A., Kaldal I., Kristinsson S.G. and Vikingsson S., 2016
Figure 9. Blue Lagoon area
Source: Author's photo (2020)
gases into the atmosphere (RagnheiSardottir et al. 2011) including hydrogen sulphide (H2S) and carbon dioxide (CO2). With increasing environmental and climate change awareness, countries around the world are seeking ways to reduce H2S and CO2 emissions to slow global warming, (following e.g. the (1997) Kyoto Protocol to the United Nations Framework Convention on Climate Change). Correspondingly, scientists in Iceland have developed procedures in which greenhouse gases from geothermal power plants
are returned into the geothermal reservoir, where they are bound in the basalt bedrock (Gislason et al. 2009; Gislason and Oelkers 2014; RagnheiSardottir et al. 2011). This is done to reduce emissions and sustain the pressure in the reservoir, making the geothermal resource more sustainable. This paper focuses specifically on two such procedures, the CarbFix and SulFix procedures (RagnheiSardottir et al., 2011; CarbFix, 2020), currently employed at the HellisheiSi Geothermal Power Plant.
Figure 10. Showing map of the geothermal power plant in HellisheiSi, referred to as
Source: National Land Survey of Iceland (2020b)
Figure 11. Shows the geology near HellisheiSi geothermal plant on Hellisheidi in Iceland
Source: (RagnheiSardottir, SigurSardottir, Kristjansdottir, Harvey, 2011)
Figure 12. Geothermal energy production and injection to ground. Figure 12 exhibits how geothermal energy is produced at HellisheiSi, through the harnessing of steam from the ground, making this a clean and sustainable way of producing electricity. As the steam makes its way through the powerhouse, goes through the condenser and becomes a condensate, the steam cools down and is transformed into outlet water, referred to as "brine". There are two outlet streams, brine or condensate
Source: Author's drownings (2020)
4. The injection process
The CarbFix procedure involves taking greenhouse gases from the geothermal steam and dissolving them in water under high pressure, then injecting them into porous basalt rock at a depth of 500 to 800 metres (Koukouzas et al. 2019). The basalt acts like a sponge and captures CO2 for permanent storage in the ground. At HellisheiSarvirkjun, a geothermal plant of Reykjavik Energy, this procedure currently
Water CO
1Í Í ..... - -
C02 gas bubbles ■ > Basaltic rock
• •
Carbonate minerals
Figure 13. Shows CO2 injection into basaltic rock, in Hellisheidi geothermal plant
Source: (Gislason and Oelkers, 2014)
binds about 33 tons of CO2 every day to rock each day (RagnheiSardottir et al. 2011).
Equation [1] (Fe2+, Ca2+, Mg2+) + CO2+H2O =
= (Fe, Ca, Mg)CO3 + 2H+
Equation [1] shows the relationship between chemical factors and the chemical reaction when CO2 is injected into the bedrock after being dissolved in water. It is attached in the bedrock iron via a process called mineralization (Rosenbauer et al. 2012; Gislason and Oelkers 2014; Alfredsson et al. 2013; Gaus 2010; Gislason et al. 2014; Gislason et al. 2010). When H2S and CO2 are dissolved in water and rushed down the injection wells, they bind with basalt rock over time, and form minerals. For every tonne of carbon dioxide bound in the bedrock, an estimated 8.8 tonnes of basalt glass is required (Arnorsson 2003; Oelkers and Cole 2008; Gislason et al. 2009).
5. Cost structure issues and analysis
The SulFix and CarbFix procedures have been analysed with the objective of estimating the potential cost ofcarbon capture and sequestration (CCS) projects (Giovanni and Richards 2010; RagnheiSardottir et al. 2011). SulFix in relation to CarbFix is similar in that it involves injecting a greenhouse gas to ground, as sulphate dissolved in water. When estimating geothermal project cost structure issues, interest has been estimated by the use of the CAPEX capital expenditure, and the OPEX operating expense (Kristjansdottir and Margeirsson 2015).
Figure 14. Author, Helga Kristjansdottir, at the Volcanic mountain March 27, 2021
Cost analysis for these kinds of procedures must take several factors into consideration. These include the capital costs (the fixed costs of setting up operations) (Kristjansdottir 2014a, 2015a) and the variable costs (the costs that change with increased production). The internal rate of return, or interest rate, is the discount rate resulting in the net present value (NPV) of a particular project being equal to zero. The net present value (NPV) is modelled to estimate cash flow in the future, taking the time value of money (TVM) into account. To compare the economic benefits of different investment projects, analysts have used the internal rate of return (IRR) to determine which projects are beneficial financially. For financial calculations, investors are also interested in the return on investment (ROI), since it shows the financial return on a particular investment, determined by the interest rates applied.
Findings show that the initial cost is mostly in the form of capital costs, after which the variable cost becomes more significant, making the investment feasible after 30 years of operation, with costs of the CarbFix project have been evaluated by RagnheiSardottir et al. (2011) by calculating the present value, IRR and EURIBOR (the Euro Interbank Offer Rate). These factors are important regarding both domestic and foreign investment (Kristjansdottir 2010, 2012, 2013, 2014, 2020; Kristjansdottir and Oskarsdottir 2020; Kristjansdottir and Margeirsson 2020), also a factor like culture (Kristjansdottir et al. 2017, 2020; Kristjansdottir and Karlsdottir, 2020).
Researchers have found that, when injecting CO2 back into the earth, approximately 80% or more of the CO2 binds to the earth basalt rockwithin a year (Gislason and Oelkers 2014).
Scientists have developed several other capture and storage procedures, with the German power market as an example (Spiecker et al. 2014; Kelektsoglou 2018; Koukouzas et al. 2009; McGrail et al. 2006; Oelkers et al. 2008; Schaef et al. 2010). These procedures help countries attract more investment (Kristjansdottir 2019a, 2020) and become more competitive (Kristjansdottir 2017).
6. Summary and conclusions
The Blue Lagoon in Iceland is created using brine from the Svartsengi geothermal power plant for bathing, near the urban settlement of Grindavik on the Reykjanes Peninsula in Iceland. Scientists have developed procedures to re-inject some of the brine from Svartsengi geothermal power plant back into the reservoir, to maintain the reservoir pressure and thus its sustainability. In addition, the focus is also on HellisheiSi geothermal power plant. Scientists have developed unique ways of dealing with the greenhouse gases coming out of the ground during the harnessing of geothermal water. These procedures, SulFix and CarbFix, fix H2S and CO2 in the rock, to reduce outlet of greenhouse gases by storing them in basalt rock - also referred to as
mineral carbonation or carbon capture and storage. This involves dissolving the greenhouse gases in water, and re-injecting them back into the ground through boreholes, in HellisheiSi.
Moreover, in the neighbourhood of the Svartsengi power plant, in the neighbourhood of the Blue Lagoon, there is injection of brine to return to reservoir ad maintain pressure in reservoir.
The paper also covers several scenarios that have already been tested to determine the financial feasibility of capture and storage. These have involved calculating the estimated internal rate of return (IRR), the return on investment (ROI) and the present value (NPV).
Calculations have shown the CarbFix project to be a feasible option contributing to decreased greenhouse gas emissions.
The objective of this article was to provide an overall picture of the operations and potential around geothermal areas. First, the article described how brine and steam are retrieved from boreholes to drive turbines for clean energy production. Second, it explained how the brine, and greenhouse gases dissolved in water are re-injected into the reservoir and then bound and stored in the basalt rock. Finally, it showed how these procedures represent an enduring and economically feasible solution.
References:
Doglioni, C. (1994). Foredeeps versus subduction zones: Geology, v. 22, p. 271-274.
Alfredsson, H.A., Oelkers, E.H., Hardarsson, B.S., Franzson, H., Gunnlaugsson, E., and Gislason, S.R. (2013). The geology and water chemistry of the Hellisheidi, SW-Iceland carbon storage site: International Journal of Greenhouse Gas Control, v. 12, p. 399-418.
Arnórsson, S. (2003). Arsenic in surface - and up to 90 °C ground waters in a basalt area, N-Iceland: Processes controlling its mobility: Applied Geochemistry, v. 18, p. 1297-1312.
CarbFix (2020). Homepage. Retrieved from: https://www.carbfix.com/ (accessed 12 March 2020).
Gaus, I. (2010). Role and impact of CO2 - Rock interactions during CO2 storage in sedimentary rocks: International
Journal of Greenhouse Gas Control, v. 4, p. 73-89.
Giovanni, E., and Richards, K.R. (2010). Determinants of the costs of carbon capture and sequestration for expanding electricity generation capacity: Energy Policy, v. 38, p. 6026-6035.
Gislason, S.R., Broecker, W.S., Oelkers, E.H., Gunnlaugsson, E., Stefansson, A., Wolff-Boenish, D., Matter, J., and Bjornsson, G. (2009). The CarbFix project: Mineral CO2 sequestration into basalt: Geochim Cosmochim Acta, v. 73, p. A440-A440.
Gislason, S.R., Broecker, W.S., Gunnlaugsson, E., Snsbjornsdóttir, S., Mesfin, K.G., Alfredsson, H.A., Aradottir, E.S., Sigfusson, B., Gunnarsson, I., Stute, M., Matter, J.M., Anarson, M.Th., Galeczka, I.M., Gudbrandsson, S., Stockman, G., Wolff-Boenish, D., Stefansson, A., Ragnheidardottir, E., Flaathen, T., Gysi, A.P., Olssen, J., Didriksen, K., Stipp, S., Menez, B., and Oelkers, E.H. (2014). Rapid solubility and mineral storage of CO 2 in basalt: Energy Procedia, v. 63, p. 4561-4574.
Gislason, S., and Oelkers, E. (2014). Carbon storage in basalt: Science, v. 344, p. 373-374.
Gislason, S.R., Wolff-Boenish, D., Stefansson, A., Oelkers, E.H., Gunnlaugsson, E., SigurSardóttir, H., Sigfusson, B., Broecker, W.S., Matter, J.M., and Stute, M. (2010). Mineral sequestration of carbon dioxide in basalt: A pre-injection overview of the CarbFix project: International Journal of Greenhouse Gas Control, v. 4, p. 537-545.
Gunnlaugsson E. (2016). Environmental management and monitoring in Iceland: Reinjection and gas sequestration at the Hellisheidi power plant. Presented at "SDG Short Course I on Sustainability and Environmental Management of Geothermal Resource Utilization and the Role of Geothermal in Combating Climate Change", organized by UNU-GTP and LaGeo, in Santa Tecla, El Salvador, September 4-10.
Kelektsoglou, K. (2018). Carbon capture and storage: A review of mineral storage of CO2 in Greece: Sustainability, v. 10, p. 4400-4417.
Kristjánsdóttir, H. (2010). Foreign direct investment: The knowledge-capital model and a small country case: Scottish Journal of Political Economy, v. 7, p. 591-614.
Kristjánsdóttir, H. (2012). Knowledge is power: Knowledge-capital model in the management of power intensive industries: International Journal of Energy Sector Management, v. 6, p. 91-119.
Kristjánsdóttir, H. (2013). Foreign direct investment in a small open economy: Applied Economics Letters, v. 20, p. 1423-1425.
Kristjánsdóttir, H. (2014a). Economics and power-intensive industries: Cham, Springer, 77 p.
Kristjánsdóttir, H. (2015). Sustainable energy resources and economics in Iceland and Greenland: New York, Springer, 82 p.
Kristjánsdóttir, H., and Margeirsson, Á. (2020). Geothermal cost and investment factors., in Reedijk, J., Reference module in chemistry, molecular sciences and chemical engineering: Waltham, Elsevier (in press). Kristjánsdóttir, H. (2017). Country competitiveness: An empirical study: Baltic Region, v. 9, p. 31-44.
Kristjánsdóttir, H., Guälaugsson, T., GuSmundsdóttir, S., and Aäalsteinsson, G.D. (2017). Hofstede national culture and international trade: Applied Economics, v. 49, p. 5792-5801.
Kristjansdottir, H. (2019a). Does investment replace aid as countries become more developed? Baltic Journal of Economic Studies, v. 5(2), p. 256-261. doi: 10.30525/2256-0742/2019-5-2-256-261
Kristjansdottir, H. (2020). Tax on tourism in Europe: Does higher value-added tax (VAT) impact tourism demand in Europe? Current Issues in Tourism, pages 1-4. doi: 10.1080/13683500.2020.1734550
Kristjansdottir H., GuSlaugsson T., GuSmundsdottir S., and ASalsteinsson G.D. (2020). Cultural and geographical distance: Effects on UK exports: Applied Economics Letters, v. 27, p. 275-279.
Kristjansdottir, H., and Karlsdottir, F.B. (2020). UK FOREIGN DIRECT INVESTMENT IN THE OECD, CULTURE AND GEOGRAPHY. Baltic Journal of Economic Studies, 6(5), 8-14. https://doi.org/10.30525/256-0742/2020-6-5-8-14
Kristjansdottir, H., and Oskarsdottir, S. (2020). EU-country and non-EU-country at the time of crisis: Foreign direct investment: Baltic Journal of Economic Studies, v. 6(3), p. 19-23. doi: 10.30525/2256-0742/2020-63-19-23
Kristjansdottir, S. (2015b). The recent economic downturn and fringe-belt creation in Reykjavik, Iceland: Urban Morphology, v. 19, p. 94-96.
Kristjansdottir S. (2017). The physical frame of planning, Nordic Experiences of Sustainable Planning: Policy and Practice, pp. 37-47. Routledge.
Kristjansdottir, S. (2019b). Roots of urban morphology: International Journal of Architecture and Planning, v. 7, p. 15-36.
Koukouzas, N., Koutsovitis, P, Tyrologou, P., Karkalis, C., and Arvanitis, A. (2019). Potential for mineral carbonation of CO2 in Pleistocene basaltic rocks in Volos region (Central Greece): Minerals, v. 9, p. 627. Koukouzas, N., Ziogou, F., and Gemeni, V (2009). Preliminary assessment of CO2 geological storage opportunities in Greece: International Journal of Greenhouse Gas Control, v. 3, p. 502-513.
Kyoto Protocol to the United Nations Framework Convention on Climate Change (1997). Third session Kyoto, 1-10 December: Retrieved from: www.cnn.com/SPECIALS/1997/global.warming/stories/treaty/index4.html (accessed 10 May 2020).
Lund M.W. (1993). Author's permission obtained for publication.
McGrail, B.P., Schaef, H.T., Ho, A.M., Chien, Y.J., Dooley, J.J., and Davidson, C.L. (2006). Potential for carbon dioxide sequestration in flood basalts: Journal of Geophysical Research - Solid Earth, v. 111.
National Energy Authority (2020). Geothermal fields in Iceland. Retrieved from: https://nea.is/geothermal/the-resource/ (accessed 10 May 2020).
Oelkers, E.H., and Cole, D.R. (2008). Carbon dioxide sequestration: A solution to a global problem: Elements, v. 4, p. 305-310.
Oelkers, E.H., Gislason, S.R., and Matter, J. (2008). Mineral carbonation of CO2: Elements, v. 4, p. 333-337.
RagnheiSardottir, E., SigurSardottir, H., Kristjansdottir, H., and Harveyd, W. (2011). Opportunities and challenges for CarbFix: An evaluation of capacities and costs for the pilot scale mineralization sequestration project at Hellisheidi, Iceland and beyond: International Journal of Greenhouse Gas Control, v. 5, p. 1065-1072. Rosenbauer, R.J., Thomas, B., Bischoff, J.L., and Palandri, J. (2012). Carbon sequestration via reaction with basaltic rocks: Geochemical modeling and experimental results: Geochimica et Cosmochimica Acta, v. 89, p. 116-133.
Schaef, H.T., McGrail, B.P., and Owen, A.T. (2010). Carbonate mineralization of volcanic province basalts: International Journal of Greenhouse Gas Control, v. 4, p. 249-261.
Spiecker, S., Eickholt, V., and Weber, C. (2014). The impact of carbon capture and storage on a decarbonized German power market: Energy Economics, v. 43, p. 166-77.
Statistics Iceland (2020). Population. Retrieved from: https://px.hagstofa.is/pxis/pxweb/is/Ibuar/Ibuar
mannfjoldi_2_byggdir_sveitarfelog/MAN02001.px/table/tableViewLayout1/?rxid=d92d22ad-d6cc-4bIa-
b749-e6a664829580 (accessed on November 3rd).
Ssmundsson, K., Sigurgeirsson, M.A., Hjartarson, A., Kaldal, I., Kristinsson, S.G., and Vikingsson, S. (2016). Geological map of southwest Iceland, 1:100 000, 2nd ed.: Reykjavik, Iceland GeoSurvey.
