Abstract
The Tazzeka Mountain, located approximately 20 km south of Taza, eastern Morocco, is composed of a Westphalian volcano-sedimentary complex. It contains rhyolitic ignimbrites with the following minerals: quartz, potassium feldspar, oligoclase-andesine, and biotite. The ignimbrites are extensively altered because of a dense network of fractures in the massif. Alteration has resulted in the formation of spheroidal rocks and saprolite, the thickness of which depends on local topography. The evolution of the biotites in the ignimbrites was investigated by microprobe analysis of the mica crystals. This technique provides data that are not accessible through classical analytical methods. Biotites are transformed into secondary clay minerals, mainly chlorites and illites; intermediate stages are related to the degree of alteration of biotite, the latter being expressed by the K2O content which decreases progressively from 7.3 to 1.3%. Next come protochlorites and chlorites sensu stricto, in which the K2O content is 0.3%. Several processes including retrodiagenesis, hydrothermal activity, fumarolic activity, and geochemical weathering contributed to the transformation of the biotites at Tazzeka.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bisdom, E.D.A., Stoops, G., Delvigne, J., Curmi, P., and Altemuller, H.J. (1982) Micromophology of weathered biotite and its secondary products. Pédologie, 32, 225–252.
Butuzova, G.Y. (1996) Iron ore sediments of the fumarole field of Santorini volcano, their composition and origin. Døklady Akademie Nauk SSSR, 168, 1400–1402.
Chalot-Prat, F. (1986) Mise en évidence d’une dépression vol-cano-tectonique associée à d’épais épanchments ignimbri-tiques hercyniens dans le Massif du Tazzeka (Maroc oriental). Revue de Geologie Dynamique et de Geographie Physique, 27, 193–203.
Chalot-Prat, F. (1990) Pétrogenèse d’un volcanisme intracon-tinental tardi-orogénique hercynien. Etude du complexe volcanique carbonifère du Tazzeka et des zones volcaniques comparables dans le Mekam et la région de Jeradu (Maroc oriental). Thesis, Université de Pierre and Marie Curie, Paris, 300 pp.
Chalot-Prat, F. and Cabanis, B. (1989) Découverte dans les volcanites carbonifères du Tazzeka (Maroc oriental) de la coexistence de diverses séries basiques, d’une série acide et d’importants phénomènes de mélanges. Comptes Rendus de l’Académie des Sciences de Paris, Série II, 308, 739–745.
Chalot-Prat, F. and Galtier, J. (1989) Découverte d’un tronc de gymnosperme dans une coulée du complexe volcanique carbonifère du Tazzeka (Maroc oriental) et sa signification paléoécologique. Comptes Rendus de l’Académie des Sciences de Paris, Série II, 309, 1735–1741.
Chalot-Prat, F. and Vachard, D. (1989) Découvertes de For-aminifères serpoukhoviens (Namurien inférieur) dans la série volcano-sédimentaire du Tazzeka (Maroc oriental). Comptes Rendus de l’Académie des Sciences de Paris, Série II, 308, 1157–1160.
Chevalier, Y. (1984) Altération météorique actuelle et paléoaltérations du socle provençal (France). Evolution comparée des roches et des eaux de lessivage cordrespondantes. Etude physico-chimique, mécanique, minéralogique et hydrogéochimique. Ph.D. thesis, Université de Nice, 691 pp.
Deer, W.A., Howie, R.A., and Zussman, J. (1964) Rock-Forming Minerals. Volume 3, Sheet Silicates. Longman, London.
Dostal, J., Jackson, G.D., and Galley, A. (1989) Geochemistry of neohelikian Nanynt plateau basalts, Border rift basin, northwestern Baffin Island, Canada. Canadian Journal of Earth Sciences, 26, 2214–2223.
Dudoignon, P., Beaufort, D., and Galley, A. (1988) Hydrothermal and supergene alterations in the granitic cupola of Montebras, Creuse, France. Clays and Clay Minerals, 36, 505–520.
Eitel, W. (1966) Silicate Science. Volume 4. Hydrothermal silicate system. Academic Press, New York, 617 pp.
Galtier, J., Phillips, T.L., and Chalot-Prat, F. (1986) Euramerican coal-swamp plants in mid-carboniferous of Morocco. Review of Palaeobotany and Palynology, 49, 93–98.
Georgalas, G.C. (1940) Die postvulkanische Fumarolentätig-keit und der Wärmehaushalt des Santorin-Vulkans. Bulletin of Volcanology, Series II, 6, 237–242.
Georgalas, G.C. and Papastamatiou, J. (1951) Über den Aus-bruch des Santorin-Vulkans von 1939–1941. Der Ktenas-Ausbruch. Bulletin of Volcanology, Series II, 11, 3–37.
Georgalas, G.C. and Papastamatiou, J. (1953) L’éruption du volcan de Santorin en 1939–1941. L’éruption du dôme Fouque. Bulletin of Volcanology, Series II, 13, 3–38.
Glasmann, J.R. and Simonson, G.A. (1985) Alteration of basalt in soils of western Oregon. Soil Science Society of America Journal, 49, 262–273.
Hey, M.H. (1954) A new review of chlorites. Mineralogical Magazine, 30, 277–292.
Huvelin, P. (1986) Le Carbonifère du Tazzeka (Maroc). Volcanisme et phénomènes de resédimentation. Comptes Rendus de l’Académie des Sciences de Paris, Série II, 303, 1483–1488.
Kodosky, L.G. and Keith, T.E.C. (1995) Further insights into the geochemical evolution of fumarolic alteration, Valley of Ten Thousand Smokes, Alaska. Journal of Volcanic and Geothermal Research, 65, 181–190.
McKeague, J.A. and De Kimpe, C.R. (1978) Manuel de méthodes d’échantillonnage et d’analyse des sols. Canadian Society of Soil Science, Ottawa, 230 pp.
Melka, K. (1966) New suggestions for the subdivision of the chlorite group. Proceedings of the International Clay Conference, Jerusalem, 1, 27–31.
Meunier, A. (1977) Les mécanismes de l’altération des granites et le rôle des microsystèmes. Etude des arènes du massif granitique de Parthenay (Deux-Sèvres). Ph.D. thesis, Université de Poitiers, 247 pp.
Newman, A. (1987) The Chemistry of Clay and Clay Minerals. Monograph Number 6. Mineralogical Society, London.
Parneix, J.C., Beaufort, D., Dudoignon, P., and Meunier, A. (1985) Biotite chloritization process in hydrothermally altered granites. Chemical Geology, 51, 89–101.
Penven, M.J., Fedoroff, N., and Robert, M. (1981) Altération météorique des biotites en Algérie. Geoderma, 26, 287–309.
Rimsaite, J.H.Y. (1967) Studies of rock-forming micas. Geological Survey of Canada. Energy, Mines, and Resources Bulletin Number 149, 82 pp.
Robillard, D. (1978) Etude structurale du Moyen Atlas septentrional (région de Taza, Maroc). Thesis, 3ième cycle. Université de Lille, 178 pp.
Roubault, M., Fabriès, J., Touret, J., and Weisbrod, A.A. (1963) Détermination des minéraux des roches au microscope polarisant. Lamarre-Poissat, eds., Paris, 365 pp.
Schorin, H. (von) (1980) Zersetzung von Kalk-Alkali-Gesteinen im rezenten Fumarolengebiet. Geologische Rundschau, 69, 226–244.
Seddoh, F.K. (1973) Altération des roches cristallines en Mor-van. Etude minéralogique, géochimique et micromorphologique, thesis, Fac. Sc. Dijon. Memoires geologiques de l’Université de Dijon. 377 pp.
Shoji, S., Fujiwara, Y, Yamada, I., and Saigusa, M. (1982) Chemical and clay mineralogy of andosoils, brown forest soils and podzolic soils formed from recent Towada ashes, northeastern Japan. Soil Science, 133, 69–86.
Stringham, B. (1964) Hydrothermal alteration of ignimbrites, Beaver County, Utah. Geological Society of America Special Paper, 76, 294.
Tazaki, K. and Fyfe, W.S. (1987) Primitive clay precursors formed on feldspar. Canadian Journal of Earth Sciences, 24, 506–527.
Weaver, C.E. and Pollard, L.D. (1973) Developments in Sedimentology. The Chemistry of Clay Minerals. Elsevier, Amsterdam, 213 pp.
Wiewiora, A. and Zeiss, Z. (1990) Crystallochemical classification of phyllosilicates based on the unified system of projection of chemical composition. II. The chlorite group. Clay Minerals, 25, 83–92.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Dejou, J., De Kimpe, C., Macaire, JJ. et al. Chemical Changes and Genesis of Secondary Minerals During the Alteration of Biotites from Ignimbrites in the Tazzeka Mountain (Morocco). Clays Clay Miner. 47, 144–155 (1999). https://doi.org/10.1346/CCMN.1999.0470204
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1346/CCMN.1999.0470204