Hostname: page-component-76fb5796d-5g6vh Total loading time: 0 Render date: 2024-04-28T04:16:13.468Z Has data issue: false hasContentIssue false
  • English
  • Français

Saponite and Vermiculite in Amygdales of the Granby Basaltic Tuff, Connecticut Valley

Published online by Cambridge University Press:  28 February 2024

Richard H. April  and
Dianne M. Keller
Richard H. April
Affiliation:
Department of Geology, Colgate University, Hamilton, New York, 13346
Dianne M. Keller
Affiliation:
Department of Geology, Colgate University, Hamilton, New York, 13346
Get access Rights & Permissions [Opens in a new window]

Abstract

Clay of apparent hydrothermal origin that fills amygdales in the Granby Basaltic Tuff (Lower Jurassic) of the Connecticut Valley was analyzed and found to consist of two exceptionally well-crystallized Fe-rich, trioctahedral 2:1 layer expandable phyllosilicates. Based on chemical and XRD analyses, the minerals were tentatively identified as saponite and vermiculite. The saponite exists predominately in the two-water hydration state, but also displays one- and three-water layer hydration states, which suggests heterogeneous layer charge distribution—a phenomenon not uncommon in smectites. The identity of the second clay remains equivocal, but XRD analyses, especially with regard to the swelling properties of the clay, indicate that it is a vermiculite. The well-crystallized nature of the Granby clay and the large size of the clay flakes (up to 1 mm) allowed us to use SEM/EDS X-ray imaging and spot analysis techniques in an attempt to detect chemical differences between the saponite and vermiculite. Results showed that the chemistry of individual crystals, within and among amygdales, was essentially uniform. This suggests that the saponite and vermiculite are chemically similar and that variations in their swelling properties result from other factors, such as crystal size, layer charge density, or charge localization within the unit layers. Crystal size differences in the Granby clay were observed with both the petrographic and scanning electron microscope. Changes in layer charge density or charge localization within unit layers could have been affected by the oxidation of Fe2+ to Fe3+, a transformation inferred from the green-to-brown color changes observed in the larger amygdales. The Granby clay is of special importance, because it is one of the few examples of a naturally occurring mixture of two well-crystallized, Fe-rich trioctahedral 2:1 layer expandable phyllosilicates with crystallochemical and swelling properties that appear to bridge the operational definitions for the smectite and vermiculite groups.

Keywords

AmygdalesBasaltFe-rich smectiteSaponiteSaponite-vermiculite intermediateSmectiteVermiculite
Type
Research Article
Information
Clays and Clay Minerals , Volume 40 , Issue 1 , February 1992 , pp. 22 - 31
Copyright
Copyright © 1992, 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.)

References

Badaut, D., Besson, G., Decarreau, A. and Rautureau, R., 1985 Occurrence of a ferrous, trioctahedral smectite in recent sediments of Atlantis II Deep, Red Sea Clay Miner 20 389 – 404 10.1180/claymin.1985.020.3.09.CrossRefGoogle Scholar
Brindley, G. W., Brown, G., 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 305 – 359.CrossRefGoogle Scholar
Cole, T. G. and Shaw, H. F., 1983 The nature and origin of authigenic smectites in some recent marine sediments Clay Miner 18 239 – 252 10.1180/claymin.1983.018.3.02.CrossRefGoogle Scholar
de la Calle, C., and Suquet, H., (1988) Vermiculite: in Hydrous Phyllosilicates (exclusive of micas), Bailey, S. W., ed., Reviews in Mineralogy 19, Mineralogical Society of America, Washington, D.C., 455–496.CrossRefGoogle Scholar
Farmer, V. C., Russell, J. D., MacHardy, W. J., Newman, A C D Ahlrichs, J. L. and Rimsaite, J. Y. H., 1971 Evidence for loss of protons and octahedral iron from oxidized biotites and vermiculites Mineral. Mag 38 121 – 137 10.1180/minmag.1971.038.294.01.CrossRefGoogle Scholar
Güven, N. and Bailey, S. W., 1988 Smectites Hydrous Phyllosilicates (exclusive of micas) 497 – 559 10.1515/9781501508998-018.CrossRefGoogle Scholar
Jackson, M. L., 1974 Soil Chemistry Analysis—Advanced Course .Google Scholar
Kawano, M. and Tomita, K., 1991 Dehydration and rehydration of saponite and vermiculite Clays & Clay Minerals 39 174 – 183 10.1346/CCMN.1991.0390209.Google Scholar
Kodama, H., De Kimpe, C. R. and Dejou, J., 1988 Ferrian saponite in a gabbro saprolite at Mont Megantic, Quebec Clays & Clay Minerals 36 102 – 110 10.1346/CCMN.1988.0360202.CrossRefGoogle Scholar
Kohyama, N., Shimoda, S. and Sudo, T., 1973 Iron-rich saponite (ferrous and ferric forms) Clays & Clay Minerals 21 229 – 237 10.1346/CCMN.1973.0210405.CrossRefGoogle Scholar
Lagaly, G., 1982 Layer charge heterogeneity in vermiculites Clays & Clay Minerals 30 215 – 222 10.1346/CCMN.1982.0300308.CrossRefGoogle Scholar
Lagaly, G. and Weiss, A., 1976 The layer charge of smectite layer silicates Proc. Int. Clay Conf., 1975, Mexico 157 – 172.Google Scholar
MacEwan, D M C Wilson, M. J., Brindley, G. W. and Brown, G., 1980 Interlayer and intercalation complexes of clay minerals Crystal Structures of Clay Minerals and their X-ray Identification London Mineralogical Society 197 – 248.CrossRefGoogle Scholar
Malla, P. B. and Douglas, L. A., 1987 Layer charge properties of smectites and vermiculites: Tetrahedral vs. octahedral Soil Sci. Soc. Amer. J 51 1362 – 1366 10.2136/sssaj1987.03615995005100050048x.CrossRefGoogle Scholar
Miyamoto, N., 1957 Iron-rich saponite from Maze, Niigata Prefecture, Japan Mineral. J. (Tokyo) 2 193 – 195 10.2465/minerj1953.2.193.CrossRefGoogle Scholar
Moore, D. M., and Reynolds, R. C., (1989) X-ray Diffraction and the Identification and Analysis of Clay Minerals: Oxford University Press, New York, 332 pp.Google Scholar
Nahon, D. B. and Colin, F., 1982 Chemical weathering of orthopyroxenes under lateritic conditions Amer. J. Sci 282 1232 – 1243 10.2475/ajs.282.8.1232.CrossRefGoogle Scholar
Newman, A C D Brown, G. and Newman, A. C. D., 1987 The chemical constitution of clays Chemistry of Clays and Clay Minerals .Google Scholar
Norrish, K. and Hutton, J. T., 1969 An accurate X-ray spectrographic method for the analysis of a wide range of geological samples Geochim. Cosmochim. Acta 33 431 – 453 10.1016/0016-7037(69)90126-4.CrossRefGoogle Scholar
Reynolds, R. C., 1985 Description of program NEWMOD for the calculation of the one-dimensional X-ray diffraction patterns of mixed-layered clays .Google Scholar
Reynolds, R. C., Bish, D. L. and Post, J. E., 1989 Diffraction by small and disordered crystals Modern Powder Diffraction 145 – 181 10.1515/9781501509018-009.CrossRefGoogle Scholar
Shapiro, L., (1975) Rapid analysis of silicate, carbonate, and phosphate rocks—revised edition: U.S. Geol. Surv. Bull. 1401, 76 pp.Google Scholar
Sherman, D. M. and Vergo, N., 1988 Optical (diffuse reflectance) and Mössbauer spectroscopic study of nontronite and related Fe-bearing smectites Amer. Mineral 73 1346 – 1354.Google Scholar
Sudo, T., 1954 Iron-rich saponite found from Tertiary iron sand beds in Japan J. Geol. Soc. Japan 59 18 – 27 10.5575/geosoc.60.18.CrossRefGoogle Scholar
Sudo, T. and Shimoda, S., 1978 Clays & Clay Minerals of Japan .CrossRefGoogle Scholar
Suquet, H., de la Calle, C. and Pezerat, H., 1975 Swelling and structural organization of saponite Clays & Clay Minerals 23 1 – 9 10.1346/CCMN.1975.0230101.CrossRefGoogle Scholar
Suquet, H. and Pezerat, H., 1987 Parameters influencing layer stacking types in saponite and vermiculite: A review Clays & Clay Minerals 35 353 – 362 10.1346/CCMN.1987.0350505.CrossRefGoogle Scholar
Suquet, H. and Pezerat, H., 1988 Comments on the classification of trioctahedral 2:1 phyllosilicates Clays & Clay Minerals 36 184 – 186 10.1346/CCMN.1988.0360214.CrossRefGoogle Scholar
Walker, G. F. and Brown, G., 1961 Vermiculite minerals The X-ray Identification and Crystal Structures of Clay Minerals London Mineralogical Society 297 – 324.Google Scholar