Early Herrin coal-swamp vegetation: Inferences from miospore floras in an abandoned paleochannel

Journal Article · Tue Jan 01 00:00:00 EST 1991 · American Journal of Botany; (USA)

OSTI ID:5747024

Willard, D A ^[1]

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1. Smithsonian Institution, Washington, DC (USA)

A small paleochannel abandoned shortly prior to accumulation of peat to form the Herrin Coal was mapped and sampled in central Illinois. Spore floras from underclays and from incremental coal samples collected within and around the paleochannel were quantified to assess vegetational responses to topographic changes. In the paleochannel, underclay floras are diverse and dominated by miospores of cordaites, with miospores of tree ferns, small ferns, and sphenopsids common. In contrast, underclays outside the paleochannel are dominated strongly by lycopod miospores. The earliest coal in the paleochannel is dominated by tree-fern miospores with subdominant cordaites; subsequent increments exhibit alternating dominance of tree-fern and lycopod miospores. Outside the paleochannel, all increments of coal are dominated by tree-fern or lycopod miospores. Underclay miospore floras indicate that a more diverse, cordaitean-rich assemblage grew along the paleochannel flanks prior to peat accumulation, rather than the lycopod-dominated flora found elsewhere. Unlike the surrounding swamp, the earliest coal in the paleochannel has an unusual miospore assemblage for the Herrin Coal. Miospore and coal compaction data both indicate that peat accumulation began in the paleochannel before extending across a broader area. These differences in miospore composition and abundance suggest that changes in topography and water-table level exerted strong control on vegetational composition of the coal swamp. This unusual exposure provides evidence that edaphic factors related to topography influenced vegetational composition in both clastic and peat-accumulating swamps.

• OSTI ID: 5747024
• Journal Information: American Journal of Botany; (USA), Journal Name: American Journal of Botany; (USA); ISSN 0002-9122
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
COAL DEPOSITS
GEOBOTANY
ILLINOIS
COAL
DEPOSITION
GEOLOGIC HISTORY
PEAT
PLANTS
SPORES
SWAMPS
TOPOGRAPHY
VARIATIONS
AQUATIC ECOSYSTEMS
BIOLOGY
BOTANY
CARBONACEOUS MATERIALS
ECOSYSTEMS
ENERGY SOURCES
FEDERAL REGION V
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
MATERIALS
MINERAL RESOURCES
NORTH AMERICA
ORGANIC MATTER
RESOURCES
TERRESTRIAL ECOSYSTEMS
USA
WETLANDS
011000* - Coal
Lignite
& Peat- Reserves
Geology
& Exploration