Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-24T06:38:52.305Z Has data issue: false hasContentIssue false

Characterization of a Mg-rich and low-charge saponite from the Neogene lacustrine basin of Eskisşehir, Turkey

Published online by Cambridge University Press:  09 July 2018

M. Yeniyol*
Affiliation:
University of Istanbul, Department of Geology, 34850 Avcilar, Istanbul, Turkey
*

Abstract

The saponite examined occurs as two 0.1 m thick layers in a Pliocene sequence consisting of dolomite and dolomitic marl. To characterize this material, mineralogical and structural analyses (XRD, SEM and FTIR), thermal analyses (DTA, TG) and chemical analyses (ICP-ES) were performed. From XRD patterns of randomly-oriented powder samples, the first basal reflection appears as an asymmetric and broad peak with d001 values varying between 16.55 and 17.32 Å. In oriented and air-dried samples, this reflection occurs between 14.45 and 16.42 Å and is fairly symmetrical with FWHM of 2.7º2θ. Oriented and ethylene glycol-solvated samples produce a rational series of basal reflections, where 001 occurs at ~17.8 Å as an intense, narrow (1.1º2θ) and fairly symmetrical reflection. Upon solvation with glycerol, the 001 reflection shifts to ~18.7 Å.

The chemical composition of this saponite is similar to stevensite. However, the structural formula of Na0.114Ca0.013K0.003(Mg2.957Al0.004Fe0.028Ti0.004)(Si3.826Al0.174)O10(OH)2 indicates that vacancies in the octahedral sheet do not exist. The negative layer charge arises nearly entirely from the substitutions in the tetrahedral sheet, with the net layer charge of –0.148, smaller than for common smectites.

Due to the XRD characteristics and particularly the layer-charge distribution, it was concluded that this mineral is a Mg-rich saponite with low layer charge. The saponite was formed by direct precipitation in an alkaline lake environment from Mg- and Si-rich solutions at high pH.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2007

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

Birsoy, R. (2002) Formation of sepiolite-palygorskite and related minerals from solution. Clays and Clay Minerals, 50, 736745.Google Scholar
Brown, G. & Brindley, G.W. (1980) X-ray diffraction procedures for clay mineral identification. Pp. 305360 in: Crystal Structures of Clay Minerals and their X-ray Identification (Brindley, G.W. & Brown, G., editors). Monograph 5, Mineralogical Society, London.CrossRefGoogle Scholar
Buey, C.S., Barrios, M.S., Romero, E.G. & Montoya, M.D. (2000) Mg-rich smectite ‘precursor’ phase in the Tagus Basin, Spain. Clays and Clay Minerals, 48, 366373.Google Scholar
Cuevas, J., Villa, R.V., Ramirez, S., Petit, S., Meunier, A. & Leguey, S. (2003) Chemistry of magnesium smectites in lacustrine sediments from the Vicalvaro sepiolite deposit, Madrid Neogene basin (Spain). Clays and Clay Minerals, 51, 457472.Google Scholar
Elton, N.J., Hooper, J.J. & Holyer, V.A.D. (1997) An occurrence of stevensite and kerolite in the Devonian Crousa gabbro at Dean Quarry, Lizard, Cornwall, England. Clay Minerals, 32, 241252.Google Scholar
Geptner, A., Kristmanndottir, H., Jansson, J. & Marteinsson, V. (2002) Biogenic saponite from an active submarine hot spring, Iceland. Clays and Clay Minerals, 50, 174185.Google Scholar
Grim, R.E. (1968) Clay Mineralogy. McGraw Hill Inc. New York, 596 pp.Google Scholar
Güven, N. & Carney, L.L. (1979) The hydrothermal transformation of sepiolite to stevensite and the effect of added chlorides and hydroxides. Clays and Clay Minerals, 27, 253269.CrossRefGoogle Scholar
Hay, R.L., Hughes, R.E., Kyser, T.K., Glass, H.D. & Liu, J. (1995) Magnesium-rich clays of the meerschaum mines in the Amboseli Basin, Tanzania and Kenya. Clays and Clay Minerals, 43, 455466.Google Scholar
Hover, V.C. & Ashley, G.M. (2003) Geochemical signatures of paleodepositional and diagenetic environments: a STEM/AEM study of authigenic clay minerals from an arid rift basin, Olduvai Gorge, Tanzania. Clays and Clay Minerals, 51, 231251.CrossRefGoogle Scholar
Jackson, M.L. (1969) Soil Chemical Analysis - Advanced Course, 2nd edition. Published by the author, Madison, Wisconsin, 895 pp.Google Scholar
Michot, L.J., Bihannic, I., Pelletier, M., Rinnert, E. & Robert, J.L. (2005) Hydration and swelling of Nasaponites: influence of layer charge. American Mineralogist, 90, 166172.CrossRefGoogle Scholar
Moore, D.M. & Reynolds, R.C. (1997) X-ray Diffraction and the Identification and Analysis of Clay Minerals. Oxford University Press, Oxford, New York, 378 pp.Google Scholar
Pelletier, M., Michot, L.J., Barres, O., Humbert, B., Petit, S. & Robert, J.L. (1999) Influence of KBr conditioning on the IR hydroxyl-stretching region of saponites. Clay Minerals, 34, 439445.Google Scholar
Polyak, V.J. & Güven, N. (2000) Authigenesis of trioctahedral smectite in magnesium-rich carbonate speleothems in Carlsbad cavern and other caves of the Guadalupe Mountains, New Mexico. Clays and Clay Minerals, 48, 317321.Google Scholar
Reynolds, R.C. (1968) The effect of particle size on apparent lattice spacings. Acta Crystallographica, A24, 319320.Google Scholar
Tottenhorst, R. & Moore, G.E. (1978) Stevensite oolites from the Green River formation of central Utah. Journal of Sedimentary Petrology, 48, 587594.Google Scholar
Xu, W., Johnston, C.T., Parker, P. & Agnew, S.F. (2000) Infrared study of water sorption on Na-, Li-, Ca-, and Mg-exchanged (SWy-1 and Saz-1) montmorillonite. Clays and Clay Minerals, 48, 120131.Google Scholar
Yeniyol, M. (1992) Geology, mineralogy and genesis of Yenidoğan (Sivrihisar) sepiolite deposit. Mineral Research and Exploration Bulletin of Turkey, 114, 7184.Google Scholar