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Chlorite Vermiculitization and Pyroxene Etching in an Aeolian Periglacial Sand Dune, Allen County, Indiana

Published online by Cambridge University Press:  02 April 2024

Scott Argast*
Affiliation:
Department of Geosciences, Indiana University-Purdue University at Fort Wayne, Fort Wayne, Indiana 46805-1499

Abstract

Weathering has etched and deeply-denticulated the constituent orthopyroxenes, and chlorite has been transformed to vermiculite in the upper 3 m of an aeolian, periglacial sand dune formed in northeastern Indiana about 13,000 b.p. Pyroxene weathering begins with the development of cleavage-parallel etch pits on {010} and {100} surfaces. These pits coalesce and eventually crop out on basal surfaces as denticulations. The mean denticulation size increases logarithmically toward the surface, and the denticulation size of the orthopyroxenes is a quantifiable feature of the weathering process. Ferruginous pendants, microboxworks of iron oxides, and other indications of iron redeposition within the ortho-pyroxene microenvironments were not observed.

Chlorite in the dune has been weathered to vermiculite. The parent chlorite is a high-Fe variety, and the transformation to vermiculate does not involve the development of a chlorite/vermiculite intermediary phase. Fe2+ is oxidized as part of the transformation process and this iron is retained in the sediment as discrete goethite and as crystalline and noncrystalline coatings on the dune grains. The vermiculite from depths shallower than 64 cm is only partly expandable and is completely collapsed by K-saturation or heat treatment. This is a hydroxy-Al vermiculite and its formation is typical of intense weathering under the acid conditions prevalent at the dune surface.

Type
Research Article
Copyright
Copyright © 1991, The Clay Minerals Society

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References

Anand, R. R. and Gilkes, R. J., 1984 Weathering of hornblende, plagioclase and chlorite in meta-dolerite, Australia Geoderma 34 261280.CrossRefGoogle Scholar
April, R.H. Hluchy, M.M. and Newton, R.M., 1986 The nature of vermiculite in Adirondack soils and tills Clays & Clay Minerals 34 549556.CrossRefGoogle Scholar
Bain, D. C., 1977 The weathering of chloritic minerals in some Scottish soils Jour. Soil Sci. 28 144164.CrossRefGoogle Scholar
Berner, R. A. and Schott, J., 1982 Mechanism of pyroxene and amphibole weathering II. Observations of soil grains Amer. Jour. Sci. 282 12141231.CrossRefGoogle Scholar
Berner, R. A., Sjoberg, E. L., Velbel, M. A. and Krom, M. D., 1980 Dissolution of pyroxenes and amphiboles during weathering Science 207 12051206.CrossRefGoogle ScholarPubMed
Bleuer, N. K., 1974 Buried till ridges in the Fort Wayne area, Indiana, and their regional significance Geol. Soc. Amer. Bull. 85 917920.2.0.CO;2>CrossRefGoogle Scholar
Bleuer, N. K. and Moore, M. C., 1978 Environmental Geology of Allen County, Indiana .Google Scholar
Brown, G., Brindley, G. W., Brindley, G. W. and Brown, G., 1980 X-ray diffraction procedures for clay mineral identification Crystal Structures of Clay Minerals and their X-Ray Identification London Mineralogical Society Monograph 5 305360.CrossRefGoogle Scholar
Coffman, C. B. and Fanning, D. T., 1975 Maryland soils developed in residuum from chloritic metabasalts having high amounts of vermiculite in sand and silt fractions Soil Sci. Soc. Amer. Proc. 39 723732.CrossRefGoogle Scholar
Douglas, L. A., Dixon, J. B. and Weed, S. B., 1977 Vermiculites Minerals in Soil Environments Madison, Wisconsin Soil Sci. Soc. Amer. 259292.Google Scholar
Eggleston, C. M., Hochella, M. F. Jr. and Parks, G. A., 1989 Sample preparation and aging effects on the dissolution rate and surface composition of diopside Geochim. et Cosmochim. Acta 53 797804.CrossRefGoogle Scholar
Eggleton, R. A., 1975 Nontronite topotaxial after hedenbergite Am. Mineral. 60 10631068.Google Scholar
Franzmeier, D. P., 1970 Particle size sorting of proglacial eolian materials Soil Sci. Soc. Amer. Proc. 34 920924.CrossRefGoogle Scholar
Grandstaff, D. E., Colman, S. M. and Dethier, D. P., 1986 The dissolution rate of forsteritic olivine from Hawaiian beach sand Rates of Chemical Weathering of Rocks and Minerals New York Academic Press 4159.Google Scholar
Hall, R. D., Martin, R. E., Colman, S. M. and Dethier, D. P., 1986 The etching of hornblende grains in the matrix of alpine tills and periglacial deposits Rates of Chemical Weathering of Rocks and Minerals New York Academic Press 101128.Google Scholar
Hall, R. D. and Michaud, D., 1988 The use of hornblende etching, clast weathering, and soils to date alpine glacial and periglacial deposits: A study from southwestern Montana Geol. Soc. Amer. Bull. 100 458467.2.3.CO;2>CrossRefGoogle Scholar
Holdren, G. R. Jr. and Berner, R. A., 1979 Mechanisms of feldspar weathering—I. Experimental studies Geochim. et Cosmochim. Acta 43 11611171.CrossRefGoogle Scholar
Jackson, M. L., 1979 Soil Chemical Analysis—Advanced Course 2nd Wisconsin Published by the author, Madison.Google Scholar
Kirschner, F. R. and Zachary, A. L., 1969 Soil Survey of Allen County, Indiana Washington, DC U.S. Dept. of Agriculture.Google Scholar
Landa, E. R. and Gast, R. G., 1973 Evaluation of crystalUnity in hydrated ferric oxides Clays & Clay Minerals 21 121130.CrossRefGoogle Scholar
Locke, W. W., 1979 Etching of hornblende grains in arctic soils: An indicator of relative age and paleoclimate Quat. Res. 11 197212.CrossRefGoogle Scholar
Locke, W. W., Colman, S. M. and Dethier, D. P., 1986 Rates of hornblende etching in soils on glacial deposits, Baffin Island, Canada Rates of Chemical Weathering of Rocks and Minerals New York Academic Press 129145.Google Scholar
Makumbi, L. and Herbillon, A. J., 1972 Vermiculitisation experimentale d’une chlorite Bull. Groupe franc. Argiles 24 153164.CrossRefGoogle Scholar
Malla, P. B., Douglas, L. A., Schultz, L. G., van Olphen, H. and Mumpton, F. A., 1987 Identification of expanding layer silicates: Layer charge vs. expansion properties Proc. Int. Clay Conf, Denver, 1985 277283.Google Scholar
Moore, D. M. and Reynold, R. C. Jr., 1989 X-Ray Diffraction and the Identification and Analysis of Clay Minerals Oxford Oxford University Press.Google Scholar
NOAA, 1978 Climates of the States, Vol. 1. Alabama-Montana Detroit Gale Research Co..Google Scholar
Proust, D., Eymery, J.-P. and Beaufort, D., 1986 Supergene vermiculitization of a magnesian chlorite: Iron and magnesium removal processes Clays & Clay Minerals 34 572580.CrossRefGoogle Scholar
Ross, G. J., 1975 Experimental alteration of chlorites into vermiculites by chemical oxidation Nature 255 133134.CrossRefGoogle Scholar
Ross, G. J. and Kodama, H., 1974 Experimental transformation of a chlorite into a vermiculite Clays & Clay Minerals 22 205211.CrossRefGoogle Scholar
Ross, G. J. and Kodama, H., 1976 Experimental alteration of a chlorite into a regularly interstratified chlorite-vermiculite by chemical oxidation Clays & Clay Minerals 24 183190.CrossRefGoogle Scholar
Schott, J. and Berner, R. A., 1983 X-ray photoelectron studies of the mechanism of iron silicate dissolution during weathering Geochim., et Cosmochim. Acta 47 22332240.CrossRefGoogle Scholar
Schott, J., Berner, R. A. and Drever, J. I., 1985 Dissolution mechanisms of pyroxenes and olivines during weathering The Chemistry of Weathering Dordrecht Reidel 3553.CrossRefGoogle Scholar
Schwertmann, U., 1964 Differenzierung der eisenoxide des bodens durch extraktion mit ammoniumoxalat-lösung Z. Pflanzenernahr. Dung., Bodenk. 105 194202.CrossRefGoogle Scholar
Siever, R. and Woodford, N., 1979 Dissolution kinetics and the weathering of mafic minerals Geochim. et Cosmochim. Acta 43 717724.CrossRefGoogle Scholar
Stoops, G., Altemüller, H.-J. Bisdom, E. B. A. Delvigne, J., Dobrovolsky, V. V., Fitzpatrick, E. A., Paneque, G. and Sleeman, J., 1979 Guidelines for the description of mineral alterations in soil micromorphology Pédologie 29 121135.Google Scholar
Sunderman, J. A. and Biggs, D. L., 1987 Fort Wayne, Indiana: Paleozoic and Quaternary geology Centennial Field Guide, Vol. 3. North-Central Section Colorado Geol. Soc. Amer., Denver 325332.CrossRefGoogle Scholar
Velbel, M. A., 1989 Weathering of hornblende to ferruginous products by a dissolution-reprecipitation mechanism Clays & Clay Minerals 37 515524.CrossRefGoogle Scholar
Vicente, M. A., Razzaghe, M. and Robert, M., 1977 Formation of aluminum hydroxy vermiculite (intergrade) and smectite from mica under acidic conditions Clay Miner. 12 101112.CrossRefGoogle Scholar
Wilson, M. J., 1986 Mineral weathering processes in podzolic soils on granitic materials and their implications for surface water acidification Jour. Geol. Soc. London 143 691697.CrossRefGoogle Scholar