Pedogenesis of black shale-influenced soils of the Knobs region of eastern Kentucky
Investigation of acid soils on forested hillslopes truncating Devonian-age black shales in the Knobs of eastern Kentucky established the impact of parent material and landscape position on colluvium occurrence and soil properties. Colluvium was thickest in headslopes, thinner in nose- and sideslopes, where illitic Typic Hapludults formed in acid gray and black shale residuum and colluvium, and sandstone colluvium. Base saturation and pH increased with depth in nose- and sideslopes, and decreased with depth in headslopes. The pH of black shale colluvium and residuum was {lt}4.0 in noseslopes, and Al saturation {gt}90%. Morphology, particle size, and TiO{sub 2}/ZrO{sub 2} ratios were used to assess parent material homogeneity and colluvium source. Compositions of soil solutions, mineral stability, and clay mineral analyses were used to evaluate illite weathering. Smectite randomly interstratified with illite was an initial illite weathering product in the noseslope black shale soil. High charge smectite (HCS), randomly interstratified with illite, predominated in noseslope pedons of black and gray shale, however. Vermiculite occurred in black and gray shale headslope pedons. Lithologic discontinuities prevented attribution of clay mineral suites solely to weathering. Soil solution compositions, clay mineral ratios, and thermodynamic stability of the clay minerals, however, suggested a weathering sequence of illite {yields} smectite {yields} HCS or vermiculite {yields} kaolinite or complete dissolution. Column leaching experiments suggested carbon, iron, and sulfur loss as the initial black shale weathering step, with silicate alteration following at a later stage. Young landscapes coupled with the loss of soluble weathering products from these soils is suggested as an explanation for the maintenance of illitic mineralogy despite undersaturation with respect to illite.
- Research Organization:
- Kentucky Univ., Lexington, KY (USA)
- OSTI ID:
- 5884300
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
KENTUCKY
OIL SHALE DEPOSITS
SOIL CHEMISTRY
ALUNITE
BLACK SHALES
CLASSIFICATION
CLAYS
COMPLEX TERRAIN
DEPTH
DEVONIAN PERIOD
DISSOLUTION
FORESTS
GEOLOGIC HISTORY
ILLITE
KAOLINITE
LEACHING
MINERALOGY
MINERALS
MORPHOLOGY
PARTICLE SIZE
PH VALUE
SANDSTONES
SMECTITE
SOILS
THICKNESS
TITANIUM OXIDES
VERMICULITE
WEATHERING
ZIRCONIUM OXIDES
ALKALI METAL COMPOUNDS
ALKALINE EARTH
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
ALUMINIUM SULFATES
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHATTANOOGA FORMATION
CHEMISTRY
DIMENSIONS
ENERGY SOURCES
FEDERAL REGION IV
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IRON COMPOUNDS
IRON SILICATES
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
MATERIALS
MINERAL RESOURCES
NORTH AMERICA
OIL SHALES
OXIDES
OXYGEN COMPOUNDS
PALEOZOIC ERA
POTASSIUM COMPOUNDS
POTASSIUM SULFATES
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SIZE
SULFATE MINERALS
SULFATES
SULFUR COMPOUNDS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
USA
ZIRCONIUM COMPOUNDS
040200* - Oil Shales & Tar Sands- Reserves
Geology
& Exploration