Abstract
Miocene volcanism in eastern Morocco is comprised of potash rich calc-alkalic and alkaline rocks. In the southern part of the area, at the base of the Guilliz massif, basic inclusions are found in latites. From a petrological, geochemical and mineralogical study of both latites and their inclusions, it appear that the inclusions represent a basic liquid quenched in the latitic magma, inside the magma chamber. As a result of the drop in pressure and crystallization, a K-rich vapour phase separated from the inclusion-forming liquid and percolated the latitic magma, increasing the K2O content of the latter and possibly triggering eruptions. The mixing process between the two magmas seems supported by density and viscosity estimations. Calculations show that for temperatures ranging from 700 °C to 1000 °C and H2O contents from 1.6 to 5%, the inclusion forming liquid is less dense than the latitic liquid and can therefore ascend into the latitic magma by interface disequilibrium and flotation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Alibert, C., andCarron, J. P., 1980,Données expérimentales sur la diffusion des éléments majeurs entre verre ou liquides de compositions basaltiques, rhyolitique et phonolitique, entre 900 °C et 1300 °C à pression ordinaire. Earth and Planetary Sc. Letters,47, p. 294–306.
Alsac, C., Cornet, G., Destombes, J. P., Hentinger, R., Lavigne, J., 1969,Etude geothermique du Maroc oriental. Rapport B.R.G.M. 69 SGL 264 GTM.
Bottinga, Y. A., andWeill, D. F., 1970,Densities of Liquid Silicate Systems Calculated from Partial Molar Volumes of Oxide Components. Amer. Jour. Sci.,269, p. 169–182.
Boyd, F. R., 1959,Hydrothermal Investigations of Amphiboles. InAbelson, P. H., ed.,Researches in Geochemistry. New York, John Wiley and Sons, p. 377–396.
Burnham, C. W., 1967,Hydrothermal Fluids at the Magmatic Stage. InBarnes, H. L.,Geochemistry of Hydrothermal Ore Deposits. Holt, Rinehart Winston Inc., New York, p. 465–514.
Burnham, C. W. andDavis, N. F., 1969,Partial Molar Volumes of Water in Albite Melts. Amer. Geophys. Union Trans.,50, p. 338.
—————, andJahns, R. H., 1962,A Method for Determining the Solubility of Water in Silicate Melts. Am. Jour. Sci.,260, p. 721–745.
Carron, J. P., andLagache, M., 1980,Etude expérimentale du fractionnement des éléments Rb, Cs, Sr, et Ba entre feldspath alcalins, solutions hydrothermales et liquides silicatés dans le système Q, Ab, Or, H2O à 2 Kb, entre 700 °C et 800 °C. Bull. Mineral.,103, p. 571–578.
Clochiatti, R., andBizouard, H., 1980,Mise en évidence de la nature du liquide parental, de son évolution par fractionnement cristallin et d’un mélange de magmas dans les produits de l’éruption fissurale du rift d’Asal (République de Djibouti). C. R. Acad. Sc., Paris,289, p. 647–650.
Donaldson, C. H., andBrown, R. W., 1977,Refractory Megacrysts and Magnesium Rich Melt Inclusions within Spinel in Oceanic Tholeiites: Indicator of Magma Mixing and Parental Magma Composition. Earth and Planet. Sci. Letters,37, p. 81–89.
Dungan, M. A., Long, P. E., Rhodes, J. M., 1978,Magma Mixing at Mid Ocean Ridges: Evidence from Legs 45 and 46 D.S.D.P. Geophys. Res. Letters,5, p. 423–425.
—————, andRhodes, J. M., 1978,Residual Glasses and Melt Inclusions in Basalts from D.S.D.P. Legs 45 and 46: Evidence for Magma Mixing. Contrib. Mineral. and Petrol.,67, p. 417–431.
Eichelberger, J. C., 1975,Origin of Andesite and Dacite: Evidence of Mixing at Glass Mountain in California and at Other Circum Pacific Volcanoes. Geol. Soc. Amer. Bull.,86, p. 1381–1391.
—————, 1978 a,Andesites in Island Arcs and Continental Margins. Relationship to Crustal Evolution. Bull. Volcanol.,41, p. 480–500.
—————, 1978 b,Andesitic Volcanism and Crustal Evolution. Nature,275, p. 21–27.
—————, 1980,Vesiculation of Mafic Magma during Replenishment of Silicic Magma Reservoirs. Nature,288, p. 446–450.
Ewart, A., 1976,Mineralogy and Chemistry of Modern Orogenic Lavas — Some Statistics and Implications. Earth and Planetary Sc. Letters,31, p. 417–432.
Gill, J., 1981,Orogenic Andesites and Plate Tectonics. Springer Verlag Berlin, pp. 385.
Gourgaud, A., Bourdier, J. L., andVincent, P. M., 1980,Mélange de magmas sursaturés et sous saturés dans le volcan du Sancy (Monts Dore, Massif central français). C. R., Acad., Sc. Paris,291, p. 175–178.
Gourgaud, A., Cantagrel, J. M., andVincent, P. M., 1981,Mélanges de magmas et pétrogenèse des trachyandésites du Mont Dore (Massif central français). C. R. Acad. Sc. Paris,293, p. 711–716.
Harry, W. T., 1950,Aluminium Replacing Silicon in Some Silicate Lattices. Mineral. Mag.,29, p. 142–149.
Heiken, G., andEichelberger, J. C.,Eruptions at Chaos Crags, Lassen Volcanic National Park, California. Jour. Volc. and Geother. Res.,7, p. 443–481.
Jambon, A., 1980,Diffusion of Water in Granitic Melt: an Experimental Study. Carnegie Inst., Yearbk.,79, p 352–355.
Jérémine, E. etMarcais, J., 1960,La région volcanique des Beni Bou Yahi (avant pays du Rif oriental). In:Livre à la mémoire du professeur P. Fallot, Soc. Géol. de France, 1, p. 431–446.
Lofgren, G. E., 1979,Experimental Studies on the Dynamic Crystallization of Silicate Melts. In:Physics of Magmatic Process, Princeton University Press, p. 487–551.
Macdonald, G. A., andKatsura, T., 1964,Chemical Composition of Hawaiian Lavas. Jour. of Petrology,5, p. 82–133.
Nelson, S. A., andCarmichael, I. S. E., 1979,Partial Molar Volumes of Oxide Components in Silicate Liquids. Contrib. Min. Petr.,71, p. 117–124.
Osborn, E. F., andWatson, E. B., 1977,Studies of Phase Relations in Subalkalic Volcanic Series. Carnegie Inst. Washington Yb.,76, p. 472–478.
Papike, J. J., Cameron, K. L., Baldwin, K., 1974,Amphibole and Pyroxenes: Characterization of OTHER Than Quadrilateral Components and Estimates of Ferric Iron from Microprobe Data. Geol. Soc. Amer. Ann. Mtg. Abstracts with program, p. 1053–1054.
Sakuyama, H., 1979,Evidence of Magma Mixing: Petrological Study of Shirouma — Oike Calc Alkaline Andesite. Jour. Volc. and Geoth. Res.,5, p. 179–208.
—————, andKushiro, I., 1979,Vesiculation of Hydrous Andesitic Melt and Transport of Alkalies by Separated Vapor Phase. Contrib. Min. Petr.,71, p. 61–66.
Shaw, H. R., 1965,Comments on Viscosity, Crystal Settling and Convection in Granitic Magmas. Amer. Jour. Sci.,263, p. 120–152.
—————, 1969,Rheology of Basalt in the Melting Range. Journ. of Petrol.,10, p. 510–535.
—————, 1972,Viscosities of Magmatic Silicate Liquids an Empirical of Prediction. Amer. Jour. Sci.,272, p. 870–893.
Sparks, R. S. J., Sigurdsson, H., Wilson, L. 1977,Magma Mixing: a Mechanism for Triggering Acid Explosive Eruptions. Nature,267, p. 315–318.
Stewart, D. B., 1979,Formation of Siliceous Potassic Rocks. In:H. S. Yoder Jr. ed.,The Evolution of the Igneous Rocks.: Fiftieth Anniversary Perspectives. Princeton University Press, p. 339–350.
Taylor, M., andBrowing, E., 1979,Structure of Mineral Glasses. I — The feldspar Glasses NaAlSi3O8,KAlSi3O8,CaAl2Si2O8. Geochim. Cosmochim. Acta,43, p. 61–75.
Westerkamp, D., 1980,Diversité, controle structural et origines du volcanisme recent dans l’arc insulaire des petites antilles. Bull. B.R.G.M., France.
Van den Bosch, J. W. H., 1969,Carte gravimétrique du Maroc au 1:500000. Notes et Mémoires du Service Géologique du Maroc, n. 234.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hernandez, J. Potassium enrichment by magma mixing and vapor exsolution: an example in the miocene volcanism of eastern Morocco. Bull Volcanol 45, 385–399 (1982). https://doi.org/10.1007/BF02597259
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02597259