Abstract
The Akiyoshi limestone plateau in western Japan is covered with terra rossa (Fe=10.8%) of about 5 m thick for one-third of the whole area. In the terra rossa, we find some nodules of limonite ore with Fe content 52%, and high aluminum clay with SiO2 20-25%, AL2O3 40-44%, Fe2O3 9.3%, H2O+18.9-22%, whore chemical composition indicates beauxite. The writer supposes the origin of limonite ore and aluminum clay as weathering residual product limestone, produced during the late Tertiary peneplanation period under either subtropical or tropical climate. Economic value of these ores should be studied in the future.
