Mechanism of feldspar weathering: Some observational evidence

Research Article| June 01, 1977 Mechanism of feldspar weathering: Some observational evidence Robert A. Berner; Robert A. Berner 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520 Search for other works by this author on: GSW Google Scholar George R. Holdren, Jr. George R. Holdren, Jr. 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520 Search for other works by this author on: GSW Google Scholar Author and Article Information Robert A. Berner 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520 George R. Holdren, Jr. 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1977) 5 (6): 369–372. https://doi.org/10.1130/0091-7613(1977)5<369:MOFWSO>2.0.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Robert A. Berner, George R. Holdren; Mechanism of feldspar weathering: Some observational evidence. Geology 1977;; 5 (6): 369–372. doi: https://doi.org/10.1130/0091-7613(1977)5<369:MOFWSO>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 SocietyGeology Search Advanced Search Abstract Scanning electron microscopy (SEM) studies of sodic plagioclase and potassium feldspars isolated from soils indicate that the dissolution of feldspar during weathering occurs primarily at sites of excess energy on the crystal surface (for example, dislocations) and not by uniform attack over the entire surface of the mineral. As a result, distinctive etch pits develop on the feldspar surface. These can be easily reproduced in the laboratory by leaching fresh feldspars with acidic HF solutions. The reaction products (clay) left by the weathering of feldspars in soils do not form a tightly adhering, protective layer. The material remaining on the feldspar surfaces after washing or ultrasonic cleaning, as seen by SEM, is patchy, discontinuous, and sufficiently hydrous that it forms micromudcracks and pulls away from the surface upon drying. Also, feldspar grains from the A horizon of a mountain soil, from which all adhering clay has been removed, do not exhibit a distinctly decationated surface layer thicker than about 30 Å, as shown by x-ray photoelectron spectroscopy (XPS). Results of this study suggest that the weathering of feldspar is controlled by chemical reaction at the feldspar-solution interface, and not by diffusion, either through aqueous solution or through a continuous protective surface layer. 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.