Hostname: page-component-76fb5796d-2lccl Total loading time: 0 Render date: 2024-04-29T14:00:58.291Z Has data issue: false hasContentIssue false

Kaolinite Stability in the Central Piedmont of Georgia

Published online by Cambridge University Press:  01 January 2024

Willard H. Grant*
Affiliation:
Emory University, Atlanta, Georgia, USA

Abstract

A study of weathered profiles from fresh rock to the surface in granitic rocks and biotite-plagioclase gneiss shows the following: 1. The particle size of the kaolin increases from not subject to estimate in fresh rock to a maximum of approximately 60 μ in the vicinity of the contact between the B horizon and the saprolite, then it decreases to approximately 13 μ in the A horizon. 2. Gibbsite occurs most abundantly when the abrasion pH of rock slurries is greater than 6 or less than 5.5. In outcrop, gibbsite is abundant in the upper soil horizons and in the partially weathered rock but is sparse in the intervening saprolite. 3. The total amount of kaolin increases steadily upward from zero in fresh rock to a maximum in the B horizon then declines sharply in the A horizon.

These data are interpreted to mean that kaolin forms, grows and is stable in saprock, saprolite and B horizon, but it is not stable in the upper B and A horizons or in the very basic environment of incipient weathering.

Type
General Session
Copyright
Copyright © The Clay Minerals Society 1964

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bouyoucos, G. J. (1928) The hydrometer method for making a very detailed analysis of soils, Soil Sci. 26, 233–8.CrossRefGoogle Scholar
Carroll, D. (1953) Description of a Montalto soil in Maryland, Soil Sci. 75, 87102.CrossRefGoogle Scholar
Carroll, D., and Jones, N. K. (1947) Laterite developed on acid rocks in southwest Australia, Soil Sci. 64, 115.CrossRefGoogle Scholar
Grant, W. H. (1963) Weathering of Stone Mountain granite, Clays and Clay Minerals, 11th Conf. [1962], pp. 6573, Pergamon Press, New York.Google Scholar
Grant, W. H. (1964) Chemical weathering of biotite-plagioclase gneiss DeKalb County, Georgia, Clays and Clay Minerals, 12th Conf. [1963], pp. 455–63, Pergamon Press, New York.Google Scholar
Keller, W. D., McGrain, P., Reesman, A. L., and Saum, N. M. This volume, p. 107.Google Scholar
Van der Merwe, C. R., and Heystek, H. (1952) Clay minerals of South African soil groups, laterites and related soils, Soil Sci. 74, 383401.Google Scholar