Fjölrit RALA - 15.06.2004, Page 107

Table 1 Weathering rates of the soil at base of selected horizons and data from other studies.
Non-vegetated Microcosms Chemical weathering rate /kmolc ha'1 year'1 Precipitation /mm year'1
Si Al Ca Mg Na
15 cm 0,40 0,11 0,47 0,17 0,02 540
80 cm 2,28 0,08 0,41 0,23 0,05 540
115 cm 4,04 1,58 0,64 0,13 0,05 540
170 cm 7,05 2,91 4,42 0,93 0,26 540
Vegetated mesocosms:
15 cm 14,25 0,23 4,29 1,37 1,37 540
80 cm 46,20 0,56 6,70 4,18 3,46 540
115 cm 46,99 0,07 9,15 9,28 3,85 540
Drainage waters into Lake Skorradalsvatn, lceland (Moulton et al., 2001):
Soil with no vegetation 1,28 no data 0,25 0,10 0,14 ca. 1500
Soil with conifer cover 3,02 no data 0,48 0,31 0,22 ca. 1500
Chemical weathering of basalt catchments in lceland (Gislason et al., 1996):
River Laxa, Vogatunga 10 no data 3,09 1,48 1,78 1731a)
River Thorsa 17 0,16 3,54 2,14 6,05 1750a)
River Ölvusa 23 0,09 3,94 2,06 5,61 2409a)
Chemical weathering of basalt catchments in lceland (Stefansson and Gislason, 2001):
River Bugda 29 0,03 7,42 3,36 no data 4930b)
River Sanda 42 0,07 8,66 2,74 1,63 6220b)
References
Amalds, O. 2004. Volcanic soils of Iceland. Catena, 36, 3-20.
Gislason, S.R., Amorsson, S. and Armannsson, H. 1996. Chemical weathering of basalt in
southwest Iceland: Effects of mnoff, age of rocks and vegetative/glacial cover. American
Joumal of Science, 296, 837-907.
Moulton, K.L., West, J. & Bemer, R.A. 2000. Solute flux and mineral mass balance
approaches to the quantification of plant effects on silicate weathering. American Joumal of
Science, 300, 539-570.
Parkhurst, D.L., Appelo, C.A.J. 1999. User’s guide to PHREEQC (Version 2)- A computer
program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical
calculations. 99-4259, 1-326.
Stefansson, A. & Gislason, S.R. 2001. Chemical weathering of basalts, Southwest Iceland:
Effect of rock crystallinity and secondary minerals on chemical fluxes to the ocean.
American Joumal of Science, 301, 513-556.
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