Mississippi delta peats - their relationship to deltaic lignites and coals

Conference · Sun Apr 01 04:00:00 EST 1984 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6575245

Kosters, E C; Bailey, A

Deltaic peats accumulate on abandoned deltaic platforms, in interdistributary basins, in abandoned channels, and as detrital bay deposits. Within these depositional settings, several parameters determine the potential for extensive peat formation: botanical parent material; climate; frequency of delta-lobe switching; subsidence; detrital influx; and marine inundation. Each factor controls the variability in ash content and mineralogical composition of the peats. Five areas were cored. Analysis of more than 2000 samples shows that the average ash content of true peats (less than 25% ash) in the Mississippi delta is 18.3%, and that 5-15% of all sediment in the upper 4.5 m (15 ft) consists of true peat. It appears then that parameters 1 and 3 inhibit extensive peat accumulation, parameter 2 is favorable, whereas 4, 5 and 6 vary depending on the depositional setting. When studying peats as precursors for coal, one should consider quality as well as quantity of the ash. Examination of ashes indicated that major components are water-soluble salts and silica. Leaching ashes with distilled water result in loss of salts and reduction of ash weights up to 77%. Scanning electron microscopy shows that abundant silica is biogenic and in a state of dissolution. Decrease of the amount of ash by natural dissolution of salts and silica during early diagenesis may result in better quality peats and more true peat overall. Organic-rich deposits in the Mississippi delta may provide examples of modern coal-forming environments if conditions are properly considered. An understanding of the processes in peats will help in deciphering the rock record with respect to deltaic lignites and coals.

• Research Organization: Louisiana Geological Survey, Baton Rouge
• OSTI ID: 6575245
• Report Number(s): CONF-8405216-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 68:4
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
011000* -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
ALLUVIAL DEPOSITS
BROWN COAL
CARBONACEOUS MATERIALS
COAL
DEPOSITION
ENERGY SOURCES
FEDERAL REGION VI
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
LIGNITE
LOUISIANA
MATERIALS
MISSISSIPPI RIVER
NORTH AMERICA
ORGANIC MATTER
ORIGIN
PEAT
RIVERS
ROCKS
SEDIMENTARY ROCKS
STREAMS
SURFACE WATERS
USA