In Iceland , the Hvanná river , located at the north flank of the Eyjafjallajökull , was heavily charged with CO2 following the 2010 eruptions . Travertine precipitated along the river . By 2014 , CO2 concentration in the river has decreased and travertine has started to dissolve . However , in places , where the river changed its bed , travertine covered rocks can still be seen
2010 eruptions
2010 eruptions of Eyjafjallajökull
Travertine