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Physical, chemical and mineralogical properties of a soil catena on shale

Four soils on a shale catena were studied in Sete Lagoas region, Minas Gerais State and theirs physical, chemical and mineralogical properties were studied. The soils belongs to the following great soil groups: Soils Bruns Acids (Oxic Humitropepts), Profile 1 located in upland Profile 2 (Typic Paleustult) located in pediment backslope and Dark Red Latosols (Typic Haplorthox) Profiles 3 and 4, located in pediment footslope. The silt content is high and it decreaces from Pedon 1 through Pedon 4, and it was inherited from parent material. There is a relationship between soil properties and the position of the soils on the landscape. The contents of base saturation, silt and 2:1 clay minerals are higher in soils located on upland and pediment blackslope than soils located on pediment footslope. Soils Bruns Acids are mineralogicaly younger than Dark Red Latosols. Mica, ikaolinite and montmorillonite were probably inherited from parente material. Gibbsite and vermiculite were formed during pedogenesis. According to mica content the following weathering sequence is suggested, going from the least to the most weathered soils: Soils Bruns Acid (Profiles 1 and 2) < Dark Red Latosol (Profile 3) < Dark Red Latosol (Profile 4). In relation to genetic implication in the studied area a general conclution is drown that all soils have been developed from reworked parent material.


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