Mineralogy and acidity of an inland acid sulfate soil of Texas

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Soil Sci. Soc. Am. J.; (United States)

DOI:https://doi.org/10.2136/sssaj1983.03615995004700040041x· OSTI ID:6812303

Carson, C D; Dixon, J B

The Aubrey soil occurs in the East Cross Timbers Region of north-central Texas. It has developed in an acid clayey shale of the Lewisville member of the Woodbine geologic formation of Upper Cretaceous age. Jarosite (KFe/sub 3/(OH)/sub 6/(SO/sub 4/)/sub 2/) occurs in localized concentrations in the lower horizons. Selected particles from the C horizon were 87.6% jarosite and served as a reference mineral for the soil. Jarosite content of the B3 and C horizons was 1.6 to 6.7% and was detectable by thermal and x-ray diffraction analyses of the whole soil. Scanning electron microscope examination indicated that the jarosite occurred as cubes and octahedra. These isometric forms suggest jarosite formation from pyrite present in the parent material. Smectite and kaolinite are the major clay constituents and they are both more poorly crystalline in the major A and B horizons than in the lower three horizons. The pH in water ranges from 5.0 in the upper B horizon at the 8-cm depth to 4.0 in the C horizon to the 152-cm depth. Exchangeable and nonexchangeable acidity increase with depth into the C horizon. The Aubrey soil has developed an accumulation of free Fe oxides above the jarosite zone, which is characteristic of an acid sulfate soil. 27 references, 4 figures, 4 tables.

• Research Organization: Southwest Texas State Univ., San Marcos
• OSTI ID: 6812303
• Journal Information: Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 47; ISSN SSSJD
• Country of Publication: United States
• Language: English

Related Subjects

510200* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACID SULFATES
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CLAYS
COHERENT SCATTERING
DIFFRACTION
FEDERAL REGION VI
KAOLINITE
MINERALOGY
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
PH VALUE
SCATTERING
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SMECTITE
SOILS
SULFATES
SULFUR COMPOUNDS
TEXAS
USA
WEATHERING
X-RAY DIFFRACTION