The effect of a Laki size eruption on the chemical denudation rates within Fellsá river catchment, NE Iceland

• Main Author: Eva Guðbjörg Líndal 1996-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2020
• Subjects: Jarðfræði; Eldgos; Skaftáreldar; Umhverfisáhrif; Efnarof; Fellsá; Volcanic eruptions; Environmental impact; Erosion; Laki; Iceland
• Online Access: http://hdl.handle.net/1946/35932

The 1783/84 Laki eruption lasted for 8 months and produced 15.1 km3 = 4.2 × 1013 kg of lava. During the eruption period it emitted about 122 Mt of SO2 into the atmosphere, of which 25 Mt is considered to have had an effect only on the southern part of Iceland. Knowledge on possible response of the chemical denudation rates during eruptions of a similar size is crucial to assess a possible effect of such eruptions on the chemical budget within the river catchment. The Fellsá river is a typical non-glaciated direct runoff river. It has a low pH buffering capacity and it is therefore expected to be sensitive to pollution sourced from volcanic eruptions. The chemical denudation rates within Fellsá catchment based on dissolved Na fluxes assessed during the hypothetical Laki eruption were higher for different amounts of scavenged SO2 comparing to the background Na fluxes calculated for the non-volcanic stage. However, they did not differ greatly for different river discharges. Small amount of scavenged SO2 can have a considerable effect on the river chemistry. The increase in dissolve fluxes can have positive effect on the biological activity but the decrease of pH is likely to have a negative effect of aquatic life in the river.