Galatia Channel:Peat Developed at Lowstand

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Peat Developed at Lowstand

Our model calls for the Springfield Coal (and, by implication, other Pennsylvanian coal seams) to be formed during eustatic lowstand under ever-wet conditions. Some previous authors, such as Flint et al. (1995)[1], Bohacs and Suter (1997)[2], and Heckel (2008)[3], maintained that peat developed during transgression. According to their view, preserving a thick peat deposit requires a rising water table because otherwise peat is oxidized and lost. Flint et al. (1995)[1] further held that most economic coal deposits developed in domed or raised mires, which excluded clastic sediment derived from nearby rivers.

However, evidence from coal-body geometry, coal petrography, geochemistry of coal and enclosing strata, and fossil-plant patterns strongly suggests that Desmoinesian coal in the Illinois Basin developed as planar, not domed, peat deposits (Cecil et al. 1985[4]; Eble et al. 2001[5]; Greb et al. 2002[6], 2003[7]; Neuzil et al. 2005[8]). Thus, peat accumulated at grade with the Galatia channel, with plants filtering clastics through the flanking belts now preserved as shaly coal. The Galatia was a river without banks or natural levees. Perennial flooding from the channel, coupled with an ever-wet climate, ongoing basin subsidence, and ongoing compaction of underlying sediment, maintained a consistently high water table throughout the duration of Springfield peat accumulation.

Primary Source

Nelson, W.J., S.D. Elrick, W.A. DiMichele, and P.R. Ames, 2020, Evolution of a peat-contemporaneous channel: The Galatia channel, Middle Pennsylvanian, of the Illinois Basin: Illinois State Geological Survey, Circular 605, 85 p., 6 pls.

References

  1. a b Flint, S., J. Aitken, and G. Hampson, 1995, Application of sequence stratigraphy to coal-bearing coastal plain successions: Implications for the UK Coal Measures, in M.K.G. Whateley and D.A. Spears, eds., European coal geology: Geological Society, London, Special Publications 82, p. 1–16.
  2. Bohacs, K., and J. Suter, 1997, Sequence stratigraphic distribution of coaly rocks: Fundamental controls and paralic examples: American Association of Petroleum Geologists Bulletin, v. 81, p. 1612–1639.
  3. Heckel, P.H., 2008, Pennsylvanian cyclothems in Midcontinent North America as far-field effects of waxing and waning of Gondwana ice sheets, in C.R. Fielding, T.D. Frank, and J.L. Isbell, eds., Resolving the Late Paleozoic Ice Age in time and space: Geological Society of America, Special Paper 441, p. 275–289.
  4. Cecil, C.B., R.W. Stanton, S.G., Neuzil, F.T. Dulong, L.F. Ruppert, and B.S. Pierce, 1985, Paleoclimate controls on Late Paleozoic sedimentation and peat formation in the central Appalachian basin: International Journal of Coal Geology, v. 5, p. 195–230.
  5. Eble, C.F., S.F. Greb, and D.A. Williams, 2001, The geology and palynology of Lower and Middle Pennsylvanian strata in the Western Kentucky Coal Field: International Journal of Coal Geology, v. 47, p. 189–206.
  6. Greb, S.F., C.F. Eble, and D.R. Chesnut, 2002, Comparison of the Eastern and Western Kentucky coal fields (Pennsylvanian), USA—Why are coal distribution patterns and sulfur contents so different in these coal fields?: International Journal of Coal Geology, v. 50, p. 89–118.
  7. Greb, S.F., W.M. Andrews, C.F. Eble, W.A. DiMichele, C.B. Cecil, and J.C. Hower, 2003, Desmoinesian coal beds of the Eastern Interior and surrounding basins: The largest tropical peat mires in Earth history: Geological Society of America, Special Paper 370, p. 127–150.
  8. Neuzil, S.G., F.T. Dulong, and C.B. Cecil, 2005, Spatial trends in ash yield, selenium, and other selected trace element concentrations in coal beds of the Appalachian Plateau region, U.S.A.: U.S. Geological Survey, Open-File Report, 2005-1330.