Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by BENINCASA, E. Articles by POPPI, L. Search for Related Content GeoRef GeoRef Citation

K-rich rectorite from kaolinized micaschist of the Sesia-Lanzo Zone, Italy

Department of Earth Sciences, Modena and Reggio Emilia University, I-41100 Modena, Italy

^* E-mail: brigatti{at}unimo.it

(Received 28 February 2000; revised 15 December 2000)

Rectorite crystals [^[4](Si_6.81Al_1.19)^[6](Al_3.26Ti_0.04Fe_0.55³⁺Mg_0.18Mn_0.01)^[12](Na_0.02K_0.88Mg_0.16Ca_0.01)O₂₀(OH)₄·0.75H₂O] found in micaschist of the Sesia-Lanzo Zone (NW Italy) were studied using a variety of techniques including microprobe analysis, infrared spectroscopy, single crystal and powder X-ray diffraction, atomic force microscopy and thermal analysis. Chemical data and exchangeable cation determination indicate that K⁺ is the dominant non-exchangeable interlayer cation, and thus is believed to occupy the mica interlayer site; Mg²⁺ together with small amounts of Ca²⁺, Na⁺ and K⁺ represent the exchangeable cations and can therefore be related to the smectite-like component. The coefficient of variation, CV, of d(00l) values (CV_natural = 0.47; CV_glycolated = 0.43) demonstrates the regularity of the mica-smectite interstratification, whereas the unit-cell parameters obtained by single crystal methods suggest different layer-stacking models.

KEYWORDS: interstratified mica-smectite, rectorite, chemistry, XRD, thermal analysis, IR spectroscopy, atomic force microscopy