Dekayir, A. and El-Maâtaoui, M. (2001) Mineralogy and geochemistry of supergene alteration of an alkali basalt from the Middle Atlas, Morocco. Journal of African Earth Sciences, 32 (4). pp. 619-633.

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In the Middle Atlas of Morocco, alkali basaltic flows record successive weathering phases during the Quaternary. In fresh basalt interior and intermediate external zones, the first weathering stage is characterised by glass dissolution and the formation of a Si-Al poorly-crystallised product. Advanced weathering phases are characterised by 10 Å halloysite, kaolinite and goethite, located within the primary minerals or as secondary products in fissures. Olivine and iddingsite are transformed into Si-rich goethite, plagioclase into halloysite and pyroxene into a mixture of halloysite + goethite. Dissolution of Ti-magnetite and ilmenite yielded Ti-rich products. In these conditions, the weathering of basalts and development of a soil matrix are accompanied by the elimination of certain chemical elements, such as Si, Ca, Na and K, and the concentration of Fe and Al. In the soil, clay minerals such as illite and vermiculite, do not have any genetic relationship with weathered basalt and were probably introduced externally. © 2002 Elsevier Science Limited. All rights reserved.

Item Type: Article
Uncontrolled Keywords: basalt; clay mineral; dissolution; geochemistry; mineral alteration; weathering, Morocco
Subjects: Earth and Planetary Sciences
Divisions: SCIENTIFIC PRODUCTION > Earth and Planetary Sciences
Depositing User: Administrateur Eprints Administrateur Eprints
Last Modified: 31 Jan 2020 15:46

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