THE COMPOSITION OF SOME AUSTRALIAN LATERITES AND "LATERITIC" GRAVES

The results of physical, chemical and mineralogical tests on samples (collected at a number of Australian sites) of lateritic gravels, hand concretions and sands suggest that the initial bonding in the laterites is due to hydrated aluminum oxides; ion oxide as haematite appeared to form a secondary bond as the material ages. The samples were analysed for contents of silica, ferrous iron, ferric ion and alumina. Micro-petrology and X-ray diffraction examinations were made, and magnetic susceptibility tests were performed. The samples were analysed for particle size and potential self-bonding. The test results indicate two modes of cementation. All samples showed evidence of segregation of both iron and aluminum oxides. The presence of aluminum oxide particularly in the bonding areas of the most intense iron segregation appeared to take the form initially of minute spherical particles that do not contribute greatly to bonding in the materials. The role of initial bonding falls entirely to aluminum oxide. As the material ages, hydrated iron oxide dehydrates and ferric oxide crystallizes as haematite that may form a secondary bond, firstly in areas of most intense iron segregation and finally as a continous bond in the material.

  • Corporate Authors:

    International Association of Engineering Geology

    De-Greift-strasse 195; P.O.B. 1080
    D 415 Krefeld 1,   Germany 
  • Authors:
    • Grant, K
  • Publication Date: 0

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Filing Info

  • Accession Number: 00126348
  • Record Type: Publication
  • Report/Paper Numbers: #231 Conf Paper
  • Files: TRIS
  • Created Date: Apr 21 1976 12:00AM