Iron oxides and rare earth elements in the clay fractions of a soil chronosequence in southern Spain. (3rd October 2016)

• Record Type: Journal Article
• Authors: Martín‐García, J. M.; Sánchez‐Marañón, M.; Calero, J.; Aranda, V.; Delgado, G.; Delgado, R.
• Is Part Of: European journal of soil science. Volume 67:Number 6(2016:Dec.)
• Page Start: 749
• Page End: 762
• Publication Date: 2016-10-03
• Subjects: Soil science -- Periodicals; 631.4
• DOI: 10.1111/ejss.12377
• Languages: English
• ISSNs: 1351-0754

Abstract

Abstract : Mineralogical (XRD), crystallochemical (DXRD), geochemical (ICP‐ms and ICP‐AES) and spectroscopic colour (DRS) properties of the clay fractions confirmed that five soils (a Fluvisol, two Calcisols and two Luvisols) on fluvial terraces in southern Spain form a genuine chronosequence that extends back to 600 ka. Analyses showed that goethite was more abundant than haematite. Both iron (hydr)oxide contents and Al substitution in goethite (mole %) increased with soil age. The Fe in the (hydr)oxides came from the transformation of illites to smectite + mixed‐layer phyllosilicates. Rare earth element contents correlated with a mafic alteration index and with soil age. Soil colours reflected variation in the proportions of calcite and iron (hydr)oxides, and became redder with age. Most soil properties were fitted by logarithmic chronofunctions that approach asymptotes at 70–100 ka. Highlights: A chronosequence is confirmed from the soil of fluvial terraces in southern Spain. Goethite exceeds haematite throughout and increases with soil age. Rare earth elements correlate with a mafic alteration index and soil age. Most soil attributes show logarithmic chronofunctions with asymptotes at 70–100 ka.