Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-22T21:38:45.486Z Has data issue: false hasContentIssue false
  • English
  • Français

Microscopy Studies of the Palygorskite-to-Smectite Transformation

Published online by Cambridge University Press:  01 January 2024

Mark P. S. Krekeler ,
Eric Hammerly ,
John Rakovan  and
Stephen Guggenheim
Mark P. S. Krekeler*
Affiliation:
Department of Environmental Science and Policy, George Mason University, Fairfax, Virginia, 22030 USA
Eric Hammerly
Affiliation:
Department of Geology, Miami University, Oxford, Ohio, 45056 USA
John Rakovan
Affiliation:
Department of Geology, Miami University, Oxford, Ohio, 45056 USA
Stephen Guggenheim
Affiliation:
Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, Illinois, 60607 USA
*
*E-mail address of corresponding author: [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The transformation process between palygorskite and smectite was studied by examining the morphological and structural relationships between these two minerals in an assemblage from the Meigs Member of the Hawthorne Formation, southern Georgia. Studied samples were related to an alteration horizon with a tan clay unit above and a blue clay unit below. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to study the mechanism of transformation.

From AFM data, both clay units contain euhedral palygorskite fibers. Many fibers are found as parallel intergrowths joined along the [010] direction to form ‘raft-like’ bundles. Degraded fibers, which are common in the tan clay, have a distinctly segmented morphology, suggesting a dissolution texture. Many of the altered palygorskite fibers in the tan clay exhibit an oriented overgrowth of another mineral phase, presumably smectite, displaying a platy morphology. This latter mineral forms along the length of the palygorskite crystals with an interface parallel to {010} of the palygorskite. The resulting grain structures have an elongate ‘wing-like’ morphology.

Imaging by TEM of tan clay material shows smectite lattice-fringe lines intergrown with 2:1 layer ribbon modules (polysomes) of the palygorskite. These features indicate an epitaxial overgrowth of smectite on palygorskite and illustrate the structural relationship between platy overgrowths on fibers observed in AFM data. The epitaxial relationship is described as {010} [001] palygorskite ‖ {010} [001] smectite.

Energy dispersive spectroscopy indicates that the smectite is ferrian montmorillonite. Polysomes of palygorskite fibers involved in these textures commonly vary and polysome widths are consistent with double tetrahedral chains (10.4 Å), triple tetrahedral chains (14.8 Å), quadruple tetrahedral chains (21.7 Å) and quintuple tetrahedral chains (24.5 Å).

The transformation of palygorskite to smectite and the resulting intergrowths will cause variations in bulk physical properties of palygorskite-rich clays. The observation of this transformation in natural samples suggests that this transformation mechanism may be responsible for the lower abundance of palygorskite in Mesozoic and older sediments.

Keywords

Atomic Force MicroscopyEpitaxyPalygorskite-sepiolitePhase TransformationSmectiteTransmission Electron Microscopy
Type
Research Article
Information
Clays and Clay Minerals , Volume 53 , Issue 1 , February 2005 , pp. 92 - 99
Copyright
Copyright © Clay Minerals Society 2005

References

Bickmore, B. Bosbach, D. Hochella, M.F. Jr. Charlet, L. and Rufe, E., (2001) In situ atomic force microscopy study of hectorite and nontronite dissolution: Implications for phyllosilicate edge surface structures and dissolution mechanisms American Mineralogist 86 411–423 10.2138/am-2001-0404.Google Scholar
Galán, E., (1996) Properties and applications of palygorskite-sepiolite clays Clay Minerals 31 443–453 10.1180/claymin.1996.031.4.01.Google Scholar
Golden, D.C. and Dixon, J.B., (1990) Low temperature alteration of palygorskite to smectite Clays and Clay Minerals 38 401–408 10.1346/CCMN.1990.0380409.Google Scholar
Golden, D.C. Dixon, J.B. Shadfar, H. and Kippenberger, L.A., (1985) Palygorskite and sepiolite alteration to smectite under alkaline conditions Clays and Clay Minerals 33 44–50 10.1346/CCMN.1985.0330105.Google Scholar
Güven, N. and Carney, L.L., (1979) The transformation of sepiolite to stevensite and the effect of added chloride and hydroxide Clays and Clay Minerals 27 253–260 10.1346/CCMN.1979.0270403.Google Scholar
Jones, B. Galán, E. and Bailey, S.W., (1988) Sepiolite and palygorskite Hydrous Phyllosillicates Washington, D.C. Mineralogical Society of America 631–674 10.1515/9781501508998-021.Google Scholar
Khoury, H.H. Eberl, D.D. and Jones, B.F., (1982) Origin of magnesium clays from the Amargosa desert, Nevada Clays and Clay Minerals 30 327–336 10.1346/CCMN.1982.0300502.Google Scholar
Kim, J. Peacor, D.R. Tessier, D. and Elass, F., (1995) A technique for maintaining texture and permanent expansion of smectite interlayers for TEM observations Clays and Clay Minerals 43 51–57 10.1346/CCMN.1995.0430106.Google Scholar
Krekeler, M. and Guggenheim, S., (2005) Defects in micro-structure in palygorskite-sepiolite minerals: A transmission electron microscopy (TEM) study American Mineralogist .Google Scholar
Krekeler, M. Guggenheim, S. and Rakovan, J., (2004) A microtexture study of palygorskite-rich sediments from the Hawthorne Formation, southern Georgia, by transmission electron microscopy and atomic force microscopy Clays and Clay Minerals 52 263–274 10.1346/CCMN.2004.0520302.Google Scholar
Leguey, S. Martin-Rubi, J.A. Casas, J. Marta, J. Cuevas, J. Alvarez, A. Medina, J.A., Churchman, G.J. Fitzpatrick, R.W. and Eggleton, R.A., (1995) Diagenetic evolution and mineral fabric in sepiolitic materials from the Vicalvaro deposit (Madrid Basin) Clays Controlling the Environment Australia CSIRO Publishing, Melbourne 383–392.Google Scholar
Merkl, R.S., (1989) A sedimentological, mineralogical, and geo-chemical study of the fuller’s earth deposits of the Miocene Hawthorne group of south Georgia-north Florida .Google Scholar
Nagy, K.L. and Blum, AE e, (1994) Scanning Probe Microscopy of Clay Minerals Boulder, Colorado The Clay Minerals Society 10.1346/CMS-WLS-7.Google Scholar
Patterson, S.H., (1974) Fuller’s earth and industrial mineral resources of the Meigs-Attapulgus-Quincy district, Georgia and Florida 10.3133/pp828.Google Scholar
Randall, B.A.O., (1956) Stevensite from the Whin Sill in the region of the North Tyne Mineralogical Magazine 32 218–229 10.1180/minmag.1959.032.246.04.Google Scholar
Weaver, C.E., Singer, A. and Galán, E., (1984) Origin and geologic implications of the palygorskite deposits of the S.E. United States Palygorskite-Sepiolite: Occurrences, Genesis, and Uses New York Elsevier 39–58.Google Scholar
Weaver, C.E. and Beck, K.C., (1977) Miocene of the S.E. United States: a model for chemical sedimentation in a perimarine environment New York Elsevier.Google Scholar