Geologia Croatica, Vol. 50 No. 1, 1997.
Original scientific paper
Glauconitic Materials from Lower Miocene Macelj-Sandstones of the Hrvatsko Zagorje, North-Western Croatia
N. Tadej
D. Slovenec
J. Tišljar
I. Inkret
Abstract
The Lower Miocene Macelj-sandstones, from the western part of Hrvatsko Zagorje, are green in colour with variable amounts of glauconitic grains. This paper presents the results of mineralogical and some petrological analysis of three characteristic samples of these sandstones.
The natural sandstone samples were analysed by polarising microscope and by X-ray powder diffraction (XRD). After separation, the pure or almost pure glauconitic materials were analysed by XRD, chemical analysis and thermal analysis (TG, DTA and DTG). The results show variation, not only in the glauconitic material of the sandstone samples, but also within individual samples. The amount of smectite layers varies from <5% to approximately 40% depending on the degree of order and the stage of glauconite evolution. This is indicated by the contents of K, Al, Fe, adsorbed water and cation exchange capacity as well as XRD powder patterns.
Keywords
Macelj-sandstones; Glauconitic materials; Glauconite; XRD powder patterns; Chemical composition; Thermal analysis; Hrvatsko Zagorje; Croatia
Hrčak ID:
16668
URI
Publication date:
30.6.1997.
Visits: 1.389 *