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

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