Chemical weathering of basalt in southwest Iceland: effects of runoff, age of rocks and vegetative/glacial

• Main Author: Sigurdur R. Gíslason
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1996
• Subjects: Laxa; Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.547.2112; http://earth.geology.yale.edu/~ajs/2001/Jun/qn060100513.pdf

ABSTRACT. River, ground, and peat water from a basaltic catchment area, Laxa ́ in Kjós Southwest Iceland, were sampled and analyzed for major element concentrations to define the effect of glassy versus crystalline basalt, the formation of secondary minerals, and runoff on fluxes of dissolved elements to the ocean. The proportions of the dissolved solids in the water samples derived from precipitation, air, and rock weathering were estimated. The amounts of Na, Mg, Ca, K, and S originating from precipitation were calculated from the respective solute/Cl marine ratios and the estimated aqueous Cl originated from precipitation, which was calculated using measured B content of the waters and B/Cl molal marine and rock ratios. The rock contribution from weathering ranged from 22 to 46 percent of the total dissolved solids of the waters. Iron and Al showed low mobility compared to Na. This was primarily due to consumption of these elements by ferrihydroxides, allophane, imogolite, and clay minerals. Also, Si and to a lesser degree Ca show apparent slightly lower mobility than Na. These results are in good agreement with these phases being dominant in the soils