Mineralogical characteristics and weathering in Texas lignite overburdens
Seven cores and five soils were investigated to characterize the mineralogy of their coarse fractions (>2..mu..m). The cores and associated soils were sampled from the Wilcox Group sediments overlying lignite at several geographical locations. Heavy-light mineral separation, XRD, IR, SEM, thin section examination, and total chemical analysis were used. Coarse fractions were dominated by quartz and contained variable amounts of weatherable minerals, including mica, K-feldspars, Na-Ca feldspars, chlorite and kaolinite. Iron-bearing minerals identified in the coarse fractions included goethite and hematite in the oxidized zones and siderite, chlorite, and pyrite in the reduced zones. Mineral distribution and abundance was related to lithology, soil pedogenic processes, and the status of oxidation of sediment. The abundance of weatherable minerals within the Wilcox Group sediments was related to lithology. The Carrizo Formation was composed mainly of quartz, whereas the Simsboro and the Calvert Bluff Formations contained substantial amounts of weatherable minerals in addition to quartz. The structural states of K-feldspars of the Wilcox Group sediments indicated a similar sediment source which suggested that variations in the sedimentation environment have greatly influenced the observed mineralogical differences. Acid sulfate weathering was investigated at five locations in east central Texas. Secondary sulfate minerals, formed as a result of pyrite oxidation, were similar to those commonly observed in acid hot spots, present in newly reclaimed land, formed on overburden materials containing pyrite.
- Research Organization:
- Texas A and M Univ., College Station (USA)
- OSTI ID:
- 6915053
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
011000* -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
ABUNDANCE
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CHLORITE MINERALS
COAL DEPOSITS
COHERENT SCATTERING
DIFFRACTION
DISTRIBUTION
DRILL CORES
ELECTRON MICROSCOPY
FEDERAL REGION VI
FELDSPARS
GEOLOGIC DEPOSITS
HEMATITE
INFRARED SPECTRA
IRON CARBONATES
IRON COMPOUNDS
IRON ORES
IRON OXIDES
IRON SULFIDES
KAOLINITE
LITHOLOGY
MICA
MICROSCOPY
MINERAL RESOURCES
MINERALOGY
MINERALS
NORTH AMERICA
ORES
OVERBURDEN
OXIDATION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PYRITE
QUARTZ
RESOURCES
SCANNING ELECTRON MICROSCOPY
SCATTERING
SIDERITE
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SIZE
SOILS
SPECTRA
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TEXAS
TRANSITION ELEMENT COMPOUNDS
USA
WEATHERING
X-RAY DIFFRACTION