Hostname: page-component-76dd75c94c-lpd2x Total loading time: 0 Render date: 2024-04-30T07:11:40.549Z Has data issue: false hasContentIssue false

Weathering of Chlorite and Vermiculite in Ultramafic Rocks of Cabo Ortegal, Northwestern Spain

Published online by Cambridge University Press:  02 April 2024

P. Buurman
Affiliation:
Department of Soil Science and Geology, Agricultural University, P.O. Box 37, 6700 AA Wageningen, The Netherlands
E. L. Meijer
Affiliation:
Department of Soil Science and Geology, Agricultural University, P.O. Box 37, 6700 AA Wageningen, The Netherlands
J. H. van Wijck*
Affiliation:
Department of Soil Science and Geology, Agricultural University, P.O. Box 37, 6700 AA Wageningen, The Netherlands
*
2Present address: Technical Centre for the Ceramic Industry, P.O. Box 40, 6994 ZG De Steeg, The Netherlands

Abstract

Chloritic veins in serpentinite and their weathering products were analyzed by X-ray powder diffraction (XRD) and X-ray fluorescence spectrometry (XRF). Chlorite formed during the Hercynian-age orogenesis had apparently been partly transformed to high-charge vermiculite during subsequent metamorphism of the rocks. The idealized structural formulae for these minerals are (Al1.9Fe3+0.2Fe2+0.4Mg9.2Cr0.2)(Si5.8Al2.2)O20(OH)16 and X1.3(Fe3+0.7Fe2+0.1Mg5.2Ni0.1)(Si5.8Al2.2)O20(OH)4, respectively. This transformation appears to have taken place by the removal of the hydroxy-interlayer from the chlorite without major effect on the rest of the structure. It is not clear whether other hydroxy-interlayered vermiculites containing less tetrahedral aluminum were intermediate weathering products or inherited minerals. The ultimate weathering product of chlorite and vermiculites was a Fe3+-rich smectite, which probably formed by precipitation from solution.

Type
Research Article
Copyright
Copyright © 1988, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

1

Publication No. 926 of the Department of Soil Science and Geology.

References

April, R. H., 1980 Regularly interstratified chlorite/ver-miculite in contact metamorphosed red beds, Newark group, Connecticut Valley Clays & Clay Minerals 28 111.CrossRefGoogle Scholar
Berre, A., Ducloux, J. and Dupuis, J., 1974 Pédogenèse sur roches ultrabasiques en climat tempéré humide: Les sols sur serpentinites du Limousin occidental Sci. du Sol 3 135146.Google Scholar
Born, G J v d and Buurman, P., 1985 Soil formation on mafic rocks of north Galicia, Spain. 1. Soils and classification Neth. J. Agricult. Sci. 33 6264.Google Scholar
Curtis, C. D., Hughes, C. R., Whiteman, J. A. and Whittle, C. K., 1985 Compositional variation within some sedimentary chlorites and some comments on their origin Mineral. Mag. 49 375386.CrossRefGoogle Scholar
Ducloux, J., Meunier, A. and Velde, B., 1976 Smectite, chlorite and a regular interlayered chlorite-vermiculite in soils developed on a small serpentinite body, Massif Central, France Clay Miner. 11 121135.CrossRefGoogle Scholar
Garcia, A. and Delgado, M., 1978 Mineralogia de las frac-ciones arenosas de suelos desarrolados sobre serpentinas en la Sierra de Carratraca (Malaga) Anal. Edafol. Agrobiol. 37 599620.Google Scholar
Istok, J. D. and Harward, M. E., 1982 Influence of soil moisture on smectite formation in soils derived from serpentinite Soil Sci. Soc. Amer. J. 46 11061108.CrossRefGoogle Scholar
Jackson, M. L., 1956 Soil Chemical Analysis—Advanced Course Madison, Wisconsin Department of Soil Science, University of Wisconsin.Google Scholar
Kanno, I., Onikura, Y. and Tokudode, S., 1965 Genesis and characteristics of brown forest soils derived from serpentine in Kyushu, Japan. 3. Clay mineralogical characteristics Soil Sci. Plant Nutr. 11 225234.Google Scholar
Lopez Lopez, M. I., Macias, F., Garcia Paz, C. and Guitián Ojea, F., 1984 Suelos de la zona húmeda espanola. X. Suelos sobre serpentinas. 3. Mineralogía Anal. Edafol. Agrobiol. 43 10551075.Google Scholar
Maaskant, P., 1970 Chemical petrology of polymeta-morphic ultramafic rocks from Galicia, NW Spain Leidse Geol. Meded. 45 237325.Google Scholar
Martin Vivaldi, J. L. and MacEwan, D. M. C., 1960 Cor-rensite and swelling chlorite Clay Miner. Bull. 4 173181.CrossRefGoogle Scholar
Nadeau, P. H., Wilson, M. J., McHardy, W. J. and Tait, J. M., 1984 Interstratified clays as fundamental particles Science 225 923925.CrossRefGoogle ScholarPubMed
Proust, D., 1982 Supergene alteration of metamorphic chlorite in an amphibolite from Massif Central, France Clay Miner. 17 159173.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
Senkayi, A. L., Dixon, J. B. and Hossner, L. R., 1981 Transformation of chlorite to smectite through regularly interstratified intermediates Soil Sci. Soc. Amer. J. 45 650656.CrossRefGoogle Scholar
Veniale, F. and van der Marel, H. D., 1963 An interstratified saponite-swelling chlorite mineral as a weathering product of lizardite rock from St. Margherita Staffora (Pavia Province), Italy Beitr. Miner. Petrogr. 9 198245.Google Scholar
Vogel, D.E., 1967 Petrology of an eclogite-and pyrigarnite-bearing polymetamorphic rock complex at Cabo Ortegal, NW Spain Leidse Geol. Meded. 40 121213.Google Scholar
Wildman, W. E., Jackson, M. L. and Whittig, L. D., 1968 Iron-rich montmorillonite formation in soils derived from serpentinite Soil Sci. Soc. Amer. Proc. 32 787794.CrossRefGoogle Scholar
Wildman, W. E., Whittig, L. D. and Jackson, M. L., 1971 Serpentine stability in relation to formation of iron-rich montmorillonite in some California soils Amer. Miner. 56 587602.Google Scholar
Wilson, M. J. and Berrow, M. L., 1978 The mineralogy and heavy metal content of some serpentinite soils in northeast Scotland Chem. Erde 37 181205.Google Scholar
Zijlstra, J., Meijer, E. L. and Buurman, P., 1985 Soil formation on mafic rocks of north Galicia, Spain. 3. Chlorite-smectite transformations in weathered chloritized amphibolite Neth. J. Agricult. Sci. 33 6769.Google Scholar