Studies of Clay Skins in a Cecil (Typic Hapludult) Soil: I. Composition and Genesis

Khalifa, E. M.; Buol, S. W.

doi:10.2136/sssaj1968.03615995003200060040x

Cited by 21 publications

(6 citation statements)

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“…Early microfabric studies of ped surfaces were conducted to document their composition, thickness, and continuity as related to pedogenesis (e.g., Frei and Cline, 1949;Cady, 1950;Hole, 1959, 1961;Flach, 1960;Heil and Buntley, 1965;Grossman et al, 1964;Khalifa and Buol, 1968;Miller et al, 1971;Gerber et al, 1974). These studies helped verify origin and function of these features.…”

Section: Soil Architecture and Soil Functionmentioning

confidence: 99%

Advancing the frontiers of soil science towards a geoscience

2006

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Section: Soil Architecture and Soil Functionmentioning

confidence: 99%

Advancing the frontiers of soil science towards a geoscience

2006

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“…Toutefois, on trouve plusieurs de ces revêtements sous forme de papules, c'est-à-dire sous forme de débris redistribués dans la matrice argilo-limoneuse de l'horizon Bt. Il y a donc à la fois présence de revêtements en apparence « fonctionnels » et de revête-ments reliques dans cet horizon, ce qui a déjà été noté en Caroline du Nord pour des sols comparables (Khalifa et Buol, 1968).…”

Section: Les Différents Types D'altéritesunclassified

Interprétation géopédologique du manteau d’altération de la Blue Ridge et des collines du Piedmont appalachien de Virginie (É.-U.A.)

Jolicoeur¹,

Bouchard²,

Kimpe³

2007

gpq

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Dans la Blue Ridge et les collines du Piedmont appalachien de Virginie centrale, le régolite est en grande partie constitué par un manteau d'altération. Son épaisseur diminue vers les sommets, mais il peut atteindre plus de 7 m au bas des versants. Le front d'altération est irrégulier et l'altérite forme des poches où l'on distingue une isaltérite sableuse et une alterite sablo-limoneuse à texture modifiée. La fraction argileuse est dominée par la kaolinite et l'halloysite. L'analyse thermogravimétrique d'échantillons totaux indique que la proportion de phyllosilicates 1/1 augmente de l'isaltérite à l'altérite à texture modifiée et aux horizons pédologiques. Elle atteint 37 % dans les horizons Bt de certains Ultisols. La gibbsite est un minéral important de plusieurs des profils étudiés. Dans les sols, les interstratifiés mica/vermiculite et la vermiculite, à caractère hydroxy-alumineux, constituent une part importante de la fraction argileuse, résultant d'une brunification acide. L'évolution géochimique globale est caractérisée par une perte précoce des bases, un appauvrissement modéré en Si et un enrichissement corrélatif en Al et en Fe. La partie supérieure du manteau d'altération est tronquée par endroits et des colluvions superficielles le recouvrent parfois en bas de pente. Des Inceptisols et des Ultisols se sont développés sur ces matériaux. Leur distribution actuelle relève d'une déstabilisation des pentes qui pourrait être contemporaine du dernier maximum glaciaire. La formation des altérites les plus évoluées remonterait au moins au Sangamonien, mais il manque de repères chronologiques et de datations absolues pour ces formations et la déstabilisation des versants dans cette région.In the Blue Ridge and Piedmont foothills of central Virginia, a widespread weathering mantle has developed in granitoid rocks. It thins out towards higher elevations but may reach values of at least 7 m at footslopes. The weathering front is irregular, limiting residuum pockets of sandy saprolite, corestones, and loamy sand nonsaprolite residuum. Kaolinite and halloysite are dominant secondary minerals in the clay fraction. DTG analysis of whole-residuum and whole-soil samples shows that 1/1 phyllosilicate contents increase upwards from saprolite to nonsaprolite residuum and to soil profiles, reaching 37 % in Bt horizons of some Ultisols. Gibbsite is a significant constituent in several profiles. In soil horizons, Al-vermiculite and Al-mica-vermiculite are major clay minerals, indicating that present pedogenetic processes are that of an acid brunification. Bulk geochemical evolution is characterized by a sharp early loss of bases, moderate depletion in Si and concomitant enrichment in Al and Fe. The residuum cover has been eroded in its upper part and is sometimes covered by thin colluvium deposits at footslopes. Inceptisols and Ultisols have developed upon both residuum and colluvium. Their present spatial distribution is related to a regional destabilization of slopes to be correlated with the last glacial maximum. Age of p...

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“…A partir desta constatação, foram separados alguns peds com cerosidade evidente, os quais foram montados em disco de alumínio e recobertos com ouro, sendo posteriormente analisados em alta resolução, por meio de microscópio eletrônico de varredura, em escalas submicroscópicas. A superfície dos canais e das faces livres dos agregados mostra feições iluviais características de solos com B textural com cerosidade, como ilustra a Figura 4G (Khalifa & Buol 1968;Fitzpatrick 1993;Schaefer 1994;Vidal-Torrado & Lepsch 1993;Moniz et al 1994;Dechen et al 1994;Schaefer 1996 a,b ).…”

Section: Micropedologiaunclassified

Gênese E Micropedologia De Solos Do Médio Jequitinhonha, De Turmalina a Pedra Azul, Mg

Campos

Schaefer

Ker

et al. 1997

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The pedogenesis and micropedology of seven selected soils from the mid-Jequitinhonha Valley werecharacterized, aiming to identify properties associated with the distribution of soils in the landscape. Podzolswere found on the top of the upper planation surface, closely associated with quartzite and its weatheringproducts. In the bottom of the tectonic depression which forms the mid-valley, soils with low cation exchangecapacity (CEC), low clay activity and presence of stony pavement are found, suggesting a change frompast, humid climate to present-day semi-arid climate. Kaolinitic soils with low Fe-oxides content undersuch regime are thought to represent relicts of former humid climates, being correlatable to the typicalYellow Latosols from the coastal tablelands (tabuleiros). In the ill-drained Quaternary plains, soils withhigher sodium contents are found, indicating the imperfect leaching under the present climatic condition.On the top of the regional, late Tertiary surface, deep Latosols occur, associated with saprolites of variouslithologies and Tertiary sediments derived from the erosion of these paleoweathering profiles. In all soils,some micropedological features confirm the polygenetic nature of the soils and landscape of the mid-Jequitinhonha, where either morphogenesis or pedogenesis have dominated, depending on climate,lithological control and tectonic activity .

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Studies of Clay Skins in a Cecil (Typic Hapludult) Soil: I. Composition and Genesis

Cited by 21 publications

References 0 publications

Advancing the frontiers of soil science towards a geoscience

Advancing the frontiers of soil science towards a geoscience

Interprétation géopédologique du manteau d’altération de la Blue Ridge et des collines du Piedmont appalachien de Virginie (É.-U.A.)

Gênese E Micropedologia De Solos Do Médio Jequitinhonha, De Turmalina a Pedra Azul, Mg

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