Reaction rate-surface area relationships during the early stages of weathering; I, Initial observations

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doi: 10.1016/0016-7037(85)90162-0
Authors:Holdren, George R., Jr.; Speyer, Patricia M.
Author Affiliations:Primary:
Univ. Rochester, Dep. Geol. Sci., Rochester, NY, United States
Volume Title:Geochimica et Cosmochimica Acta
Source:Geochimica et Cosmochimica Acta, 49(3), p.675-681. Publisher: Pergamon, Oxford, International. ISSN: 0016-7037
Publication Date:1985
Note:In English. 26 refs.; 2 tables
Summary:Five size fractions of alkali feldspar with specific surface areas over a X20 range were studied. At any given pH value, the bulk dissolution rates (moles/g/h) for the five fractions varied by less than a factor of two. The results suggest that reactions at crystalline defects dominate weathering processes during the early stages of dissolution. Furthermore, the exposure of these defects is not simply or easily related to total surface area. These findings strongly suggest that care must be taken to distinguish between the surface-reaction-controlled mechanism and a surface-area- controlled model which is frequently - and incorrectly - assumed to be equivalent. The data presented here are consistent with the former mechanism but strongly dispute the latter. [C.M.B.H.]
Subjects:Alkali feldspar; Chemical weathering; Defects; Feldspar group; Framework silicates; Geochemistry; Grain size; Minerals; Processes; Silicates; Solution; Weathering; Reactions
Abstract Numbers:86M/0468
Record ID:1985049615
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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