Clay minerals associations in palaeoweathering profiles from Central Spain: genesis and implications

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Doval, Mercedes and Martín García, Rebeca and La Iglesia Fernández, Ángel and Alonso-Zarza, Ana María (2012) Clay minerals associations in palaeoweathering profiles from Central Spain: genesis and implications. Clay minerals, 47 (1). p. 117. ISSN 0009-8558

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Official URL: https://www.cambridge.org/core/journals/clay-minerals



Abstract

This study examines part of the thick palaeoweathering mantle that formed on the northern area of the Spanish Central System. The study of a compound profile indicates that despite weathering processes, the primary structure of the metamorphic rocks is preserved, and is only partially lost in some intervals of the upper part of the compound profile. Macro/micromorphology, mineralogy and geochemical changes within the profiles revealed two weathering paths. In the first path, Fe-chlorite weathered to chlorite-smectite mixed-layer/smectite/kaolinite+ iron oxides. In the second path, biotite and/or muscovite weathered to kaolinite + iron oxides. The profiles show a progressive decrease, from base to top, in mica and mixed-layers and an increase in smectite and kaolinite. Thus, the profiles only comprise the lower or intermediate zones of the weathering mantle. The weathering occurred under humid climates; the lower zones of the profiles were poorly drained, whereas the topmost zones were better drained and more oxidizing. The results obtained indicate that detailed mineralogical studies are very useful to reconstruct the characteristics of the weathering mantles, and as palaeogeographic and palaeoclimatic indicators.


Item Type:Article
Uncontrolled Keywords:Palaeoweathering profiles, Spanish Central System, Smectite, Mixed-layers, Kaolinite, Humid climates.
Subjects:Sciences > Geology > Mineralogy
Sciences > Geology > Petrology
ID Code:69066
Deposited On:13 Dec 2021 09:17
Last Modified:13 Dec 2021 09:17

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