Silicate dissolution influence on Filson Creek chemistry, northeastern Minnesota

Abstract

Research Article| December 01, 1984 Silicate dissolution influence on Filson Creek chemistry, northeastern Minnesota D. I. SIEGEL; D. I. SIEGEL 1Department of Geology, Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13210 Search for other works by this author on: GSW Google Scholar H. O. PFANNKUCH H. O. PFANNKUCH 2Department of Geology and Geophysics, Pillsbury Hall, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1984) 95 (12): 1446–1453. https://doi.org/10.1130/0016-7606(1984)95<1446:SDIOFC>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation D. I. SIEGEL, H. O. PFANNKUCH; Silicate dissolution influence on Filson Creek chemistry, northeastern Minnesota. GSA Bulletin 1984;; 95 (12): 1446–1453. doi: https://doi.org/10.1130/0016-7606(1984)95<1446:SDIOFC>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The chemistry of surface water, precipitation, and ground water in Filson Creek watershed was studied to evaluate the kinetics of dissolution of silicate minerals in a natural watershed underlain by troctolite. Annual chemical budgets in 1977 showed net losses of dissolved silica, bicarbonate, calcium, magnesium, and sodium of about 31.0, 19.6, 4.8, 3.8, and 2.1 kg per hectare per year, respectively, and net gains of dissolved potassium and sulfate of 0.4 and 8.9 kg/ha/yr. On a molar basis, about 1.5 times as much magnesium was lost as was calcium, even though the amount of mafic minerals in till and bedrock underlying the watershed is about 10 times less than the amount of calcic plagioclase. Molar concentrations of magnesium in base flow and ground water were about the same as concentrations of calcium and sodium. These field data indicate that magnesium loss from the mafic minerals may be faster than either calcium or sodium loss from plagioclase.Stoichiometric "reconstruction" of primary minerals from base-flow water chemistry and kaolinite was done as a first approximation to evaluate the rates of loss. The calculations indicated that the release of magnesium from mafic minerals would have to be more than ten times faster than the release of calcium and sodium from plagioclase to account for the amount of magnesium in base flow. These calculations compare favorably with experimental linear rates of cation and silica release from forsterite, enstatite, augite, and labradorite. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.