Foram estudados dez perfis de solos representativos da Bacia Sedimentar do Recôncavo Baiano com objetivo principal de obter informações da mineralogia da fração argila e determinar a sequência de intemperização dêsses solos. Para tanto, foram coletados dois perfis de Podzólico Vermelho Amarelo e oito de Grumussolos. Estes perfis foram caracterizados morfológica, física e quimicamente. Amostras de argila de cada horizonte dos dez perfis foram obtidas através de fracionamento de rotina em amostras de solos. Estas amostras sofreram pré-tratamento para eliminação de sais solúveis, matéria orgânica e óxidos de ferro livres. Em seguida foram analisadas qualitativa e quantitativamente para determinar sua composição mineralógica. Os resultados analíticos indicam que a composição dos perfis de Podzólico Vermelho Amarelo foi caolinita (51,0 a 66,7%), mica (10,2 a 21,8%), material amorfo (3,4 a 12,3%) e montmorilonita - (3,0 a 8,5%) e para os Grumussolos foi a montmorilonita (40,4 a 59,4% mica (11,7 a 23,2%) caolinita (0,0 a 21,7%) e material amorfo (2,7 a 11,1%). A sequência de intemperização proposta, com base nos resultados mineralógicos, é a seguinte: BS₈ < BS₄ = BS₅ = BS₆ = BS₇ < BS₉ < BS₁₀. BS₂ < BS₁. Tendo em vista os resultados obtidos, os dez perfis foram, tentativamente, classificados ao nível de família da seguinte forma: perfis BS₁ e BS₂ - Oxic Tropudult, fine, kaolinitic, isohypertermic. perfis BS₃ e BS₇ - Typic Chromudert, fine, montmorillonitic, isohypertermic. perfis BS₅, BS₆ e BS8 - Typic Chromudert, very fine montmorillonitic, isohypertermice perfis BS₄ e BS₉ - Lithic-Vertic-Eutropept, fine, montmorillonitic, isohypertermic. perfil BS₁₀ - Lithic-Vertic-Eutropept, fine, kaolinitic, isohypertermic.

Ten soil profiles representative of the region know as “Recôncavo Baiano” (Sedimentary Basin) were studied objective of collecting information on the mineralogy tive clay fractions to determine two of the profiles were taken from soils previously known to be Red-Yellow Podzolic and eight from Grumusols. These profiles were morphologically described in the field and chemically and physically characterized in the laboratory. Clay fraction samples were obtained from each horizon of the ten profiles through routine fractionation of the soil sample. These were pre-treated to eliminate soluble salts, organic matter and free iron oxides. The samples were then analyzed qualitatively and quantitatively to determine their mineralogical composition. The results from these analysis indicated that the composition of the two Red-Yellow Podzolic was Kaolinite (51,0 to 66,7%), mica (10,2 to 21,8%), amorphous material (3,4 to 12,3%) and montmorillonite (3,0 to 8,5%). For the eight Grumusol profiles it was found to be montmorillonite (40,4 to 59,4%), mica (11,7 to 23,2%), kaolinite (0,0 to 21,7%) and amorphous material (2,7 to 11,1%). The weathering sequence that follows of the ten profiles under study is proposed on the basis of their individual weathering means (W.M.). BS₈ < BS₃ = BS₄ = BS₅ = BS₆ = BS₇ < BS₉ < BS₁₀ < BS₂ < BS₁. In view of the results obtained the ten profiles were tentatively classified at the family level according to the Comprehensive System of Soil Classification (Soil Survey Staff). profiles BS₁ and BS₂ - Oxic Tropudult, fine, kaolinitic, isohypertermic. profiles BS₃ and BS₇ - Typic Chromudert, fine, montmorillonitic, isohypertermic. profiles BS₅, BS₆ and BS₈ - Typic Chromudert, very fine, montmorillonitic, isohypertermic. profiles BS₄ and BS₉ - Lithic-Vertic-Eutropept, fine, montmorillonitic, isohypertermic. profil BS₁₀ - Lithic-Vertic-Eutropept, fine, kaolinitic, isohypertermic.