Characteristics of peat deposits in Mississippi River delta plain
Variations in organic-rich sediment (peat) from the Mississippi River delta plain can be explained by differences in three interrelated parameters: (a) depositional setting, (b) balance between subsidence and detrital influx, and (c) marine inundation. Variations are observed in geomterty of the overall deposits, organic matter content, and the mineralogy of peats and related ashes. Using a vibracorer, samples were collected from two brackish areas (Avery Island/Sale-Cypremort and Barataria basin) and one freshwater area (Gueydan). Peats in all areas average 90% moisture content. Dried peat averages 81.3% organic matter with a bulk density of 0.12 g/cm/sup 3/. Holocene differential compaction has been minimal (< 4%). Conventional ash values indicate different distribution of organic materials for the two brackish areas. For the area containing interdistributary peats, approximately 5% of the subsurface contains more than 70% organic matter, whereas for blanket peats, 14% of the section has more than 70% organic matter. Mineralogic data collected on low-temperature ashes indicate that major minerals in brackish peat consist of kaolinite, quartz, and water-soluble salts, whereas minerals from freshwater samples are primarily kaolinite and quartz. X-ray diffraction and electron microscopy show the presence of smectite, illite, abundant siliceous spicules, framboidal pyrite, biotite, pyroxene, and rutile in the insoluble fraction. Superficial examination of data generated so far suggests that only thin coal seams with high ash would be produced. However, the presence of decomposing siliceous sponge spicules in the ash and the possiblity of ash being leached by fresh ground water, suggest that much ash may be lost during early diagenesis.
- Research Organization:
- Louisiana Geological Survey, Baton Rouge
- OSTI ID:
- 6850003
- Report Number(s):
- CONF-8310301-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 67:9; Conference: American Association of Petroleum Geologists eastern section meeting, Carbondale, IL, USA, 3 Oct 1983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GULF COAST
PEAT
BULK DENSITY
CHEMICAL COMPOSITION
MINERALOGY
VOLATILE MATTER
DEPOSITION
GEOLOGIC MODELS
QUATERNARY PERIOD
RIVER DELTAS
CENOZOIC ERA
COASTAL REGIONS
DENSITY
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC AGES
MATTER
NORTH AMERICA
ORGANIC MATTER
PHYSICAL PROPERTIES
USA
011000* - Coal
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010600 - Coal
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