Pyrite in coal: its forms and distribution as related to the environments of coal deposition in three selected coals from western Pennsylvania. [66 refs]
The environment of deposition of coals is reflected in the general macroscopic appearance and microscopic composition of the seam. Samples from fresh-water paleoenvironments are homogeneous in appearance and composition, but samples from a marine-brackish paleoenvironment display marked variations in appearance and composition. The large majority of pyrite occurrences appear to be of primary origin. Pyrite occurrences show a tendency to be localized in dull layers of the seam. However, the majority of pyrite occurrences are related to vitrinite, probably indicating that anaerobic bacteria might prefer to colonize the woody (vitrinite) fragments. Dull layers may reflect the influx of water flow with consequent availability of sulfate ions and iron-rich clays. Pyrite deposition is particularly favored by a marine-brackish environment, as this implies the most adequate conditions for the abundance of reactants, and the action of sulfate-reducing bacteria. The pyrite content of the Lower Kittanning seam, which was deposited in a transgressive cycle, is highest in the brackish phase of the seam (kittosite and clastocite phytostromes). Pyrite distribution in the samples of the coals deposited in a fresh-water paleoenvironment, tends to be more uniform. Pyrite occurs in a wide range of sizes and shapes, but by far the most abundant occurrences are microscopic noncrystalline blebs that appear to be present equally in the marine-brackish and fresh-water samples, but they tend to be larger in freshwater samples.Small crystals forming framboidal pyrite were found to be more abundant in the marine-brackish phase of the samples, and they tend to be absent as the environment became more freshwater. Euhedral pyrite contents appear to decrease as the environment became more freshwater. Dendritic pyrite appears to be less abundant as the environment became more marine.
- Research Organization:
- Pennsylvania State Univ., University Park (USA). Coal Research Section
- OSTI ID:
- 7303609
- Report Number(s):
- SR-110
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL
CHEMICAL COMPOSITION
PYRITE
CHEMICAL ANALYSIS
DISTRIBUTION
BACTERIA
CLAYS
COALIFICATION
CRYSTAL STRUCTURE
IRON
SULFATES
CARBONACEOUS MATERIALS
CHALCOGENIDES
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
IRON COMPOUNDS
IRON SULFIDES
METALS
MICROORGANISMS
MINERALS
ORES
OXYGEN COMPOUNDS
PYRITES
SULFIDES
SULFUR COMPOUNDS
SULFUR ORES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
010600* - Coal
Lignite
& Peat- Properties & Composition