02188naa a2200217 a 450000100080000000500110000800800410001910000170006024500740007726000090015152015610016065000110172165000210173265000090175365300160176265300340177865300250181265300220183770000210185977300900188020938022021-01-22       1979    bl uuuu     u00u1 u    #d1 aKITAGAWA, Y.  aClay mineralogy of some typical soils in the Brazilian Amazon Region.  c1979  aThee outline ofthe mineral composition in the clay fraction of some typical soils oecuring in the Brazilian Amazon region is as follows: In the sofis with oxic B horizon, Yellow Latosols, Red-Yellow Latosols and `Latosols Roxo` Soil, kaolinite is predominant, goethite and haernatite are found in general, an gibbsite is frequently detected. A small amount or trace of mica minerals occur in several lateritic sofis. The presence of the other 2:1-type elay minerals is rare in the lateritic soils. In Red-Ye1Iow Podzolic soils, kaolinite is also predominant, and iron-oxide míncrals are always identified. Considerable arnount of gibbsite and small amounts of mica minerals and dioctahedral vermiculíte are present in some of these soils. In the so-called -Terra Roxa Estruturada` soils, kaolin minerals are dominant, but considerable amounts of iron-oxide minerals are found in the clay fraction, so that haernatite is especially rich. Metahalloysite is a dominant clay mineral in a `Terra Roxa Estruturada` Soil. A small amount of dioctahedral vermiculite is present in the other soils. The clay mineral composítion of the low land sofis is a little complicated. MontmorWoniteldioetahedral-vermiculite interstratified mineral and mica minerals are dominant in two Low-Hurnic Gley soils and a Ground-Water Laterite soils, respectively, although kaolin minerals are predominant in many lowland soils. Small arnounts of 2:1-type clay minerals are frequently detected in the other lowland soils. Quartz exists in the clay fraction of all the soil samples.  aArgila  aQuímica do Solo  aSolo  aAmazon soil  aMineralogia de argila em solo  asoil clay mineralogy  aSolo da Amazônia1 aMOLLER, M. R. F.  tPesquisa Agropecuária Brasileira, Brasília, DFgv. 14, n. 3, p. 201-228, jul. 1979.