HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Karathanasis, A. D. Articles by Hajek, B. F. Search for Related Content PubMed Articles by Karathanasis, A. D. Articles by Hajek, B. F. Agricola Articles by Karathanasis, A. D. Articles by Hajek, B. F.

Stability Relationships in Kaolinite, Gibbsite, and Al-hydroxyinterlayered Vermiculite Soil Systems¹

ABSTRACT

The stability of common soil minerals found in Ultisols was studied relative to their natural soil solution composition. The mineralogy of the clay fraction (<2 µm) ranged from 22 to 60% in kaolinite, 0 to 20% in gibbsite, 17 to 57% in hydroxyinterlayered vermiculite (HIV), and 1 to 12% in quartz. Ion activity functions (pH-pAl and pH₄SiO₄) of soil solutions plotted on a stability diagram along with solubility lines of soil kaolinite, gibbsite, and HIV with the formula K_0.24Ca_0.08(Si_3.24Al_0.76)(Al_1.56Fe_0.24Mg_0.20)[Al_1.45(OH)_3.79]O₁₀(OH)₂ indicated all solutions to be supersaturated with respect to reference kaolinite. Only a few surface soils containing gibbsite had solutions oversaturated relative to gibbsite. Solubility products of HIV were very close to its estimated pk, indicating a near-equilibrium condition with this mineral, especially in eluviated and transitional subsoil horizons (E and EB). Although the HIV appeared to be metastable relative to reference kaolinite, the data indicated a possible equilibrium coexistence of the two minerals with an HIV stability field below or above that of soil kaolinite, depending on the degree of Al-hydroxyinterlayering.

¹ Contribution from the Dep. of Agronomy and Soils, Alabama Agric. Exp. Stn., Auburn Univ., AL 36849.

² Formerly Research Associate and Professors of Soils, respectively. The senior author is presently Assistant Professor, Dep. of Agronomy, Univ. of Kentucky, Lexington, KY 40546.

Received for publication March 22, 1983. Accepted for publication July 11, 1983.

This article has been cited by other articles:

				M. Aide and C. Smith-Aide Assessing Soil Genesis by Rare-Earth Elemental Analysis Soil Sci. Soc. Am. J., September 1, 2003; 67(5): 1470 - 1476. [Abstract] [Full Text] [PDF]