Iron oxides in tropical soils on various parent materials

W. Wiriyakitnateekul, A. Suddhiprakarn, I. Kheoruenromne, Michael Smirk, Robert Gilkes

    Research output: Contribution to journalArticlepeer-review

    19 Citations (Scopus)


    Twenty nine Fe oxide concentrates of Thai soils formed on basalt, sandstone, shale/limestone and granite were investigated. Goethite and hematite are relatively more abundant in granitic and basaltic soils, respectively. Values of Fe-o/Fe-d range from 0.01 to 0.28 indicating that free Fe oxides are mostly crystalline.There are no systematic differences in unit-cell dimensions for goethite and hematite in soils on different parent materials. Mean crystallite dimensions calculated from the 110 reflections are greater for hematite than for goethite. Aluminium substitution varies from 8 to 24 mole% for goethite and from 4 to 17 mole% for hematite. The dehydroxylation temperature for goethite ranges from 285 degrees C to 320 degrees C. The goethite in basaltic soils has a smaller crystal size and Al substitution, as well as a lower dehydroxylation temperature, compared to soils on other parent materials. The dehydroxylation temperature of goethite is positively related to Al Substitution (R = +0.58), MCD 110 (R = +0.49) and Al-d (R = +0.53). The Mn, Ni, Cr, V and P in these Soils Occur in Fe oxides rather than as discrete minerals.
    Original languageEnglish
    Pages (from-to)437-451
    JournalClay Minerals
    Issue number4
    Publication statusPublished - 2007


    Dive into the research topics of 'Iron oxides in tropical soils on various parent materials'. Together they form a unique fingerprint.

    Cite this