Boiling, foul-smelling mud pot (solfatara), Reykjadalur, Hveragerdi High Temperature Geothermal Area, South West Iceland

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In a high temperature geothermal field, where the water temperature is 180C (356F) at a depth of 125m, the surface rocks are extensively altered into clay. This is due to the hydrogen sulphide in the hot waters being oxidised into sulphuric acid, so making the water sufficiently acid to dissolve minerals from the surface rocks, so altering them into clay, which is coloured grey by iron sulphide (iron combining with hydrogen sulphide). If the clay pot contains sufficient hot water, the mud boils.

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Size: 5218px × 3465px
Location: Reykjadalur, Hveragerdi, 40 km east of Reykjavik, South West Iceland
Photo credit: © robert harrison / Alamy / Afripics
License: Royalty Free
Model Released: No

Keywords: acid, alteration, boiling, change, clay, climate, energy, field, formation, geography, geology, geothermal, global, high, hot, iceland, mud, pot, renewable, rock, solfatara, steam, surface, temperature, tourism, travel, vapours, vulcanism, warming, waters