Galatia Channel:Peat Developed at Lowstand

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	Abstract
	Introduction Geologic Setting Previous Research Crevasse-Splay Model Cyclicity and Sequence Stratigraphy
	Stratigraphy Houchin Creek Coal Excello Shale Member Hanover Limestone Member Delafield Member (New) Galatia Member (New) Underclay of Springfield Coal Springfield Coal Dykersburg (Shale) Member Turner Mine Shale Member St. David Limestone Member Summary
	Other Channels Related to the Galatia Channel Sullivan Channel Effingham Channel Leslie Cemetery Channel Other Channels
	Similar Channels Affecting Other Coal Seams Colchester Coal and Francis Creek Shale Herrin Coal, Energy Shale, and Walshville Channel Baker Coal and Winslow-Henderson Channel Danville Coal Murphysboro Coal and Oraville Channel
	Discussion Model of Channel Development Linkage of Climate and Eustasy Peat Developed at Lowstand Rapid Transgression, Gradual Regression Relationship of Effingham and Galatia Channels
	Channels and Cyclothems: A Summary Model The “Typical” Cyclothem on a Cratonic Platform Cyclothem Models Do not Address Contemporaneous Channels The Gray Shale Wedge and Its Relationship to the Channel
	Conclusions
	Acknowledgments
	References
	Appendix
	Figures
	Plates

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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), Bohacs and Suter (1997), and Heckel (2008), 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. further held that most economic coal deposits developed in domed or raised mires, which exclude 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; Eble et al. 2001; Greb et al. 2002, 2003; Neuzil et al. 2005). 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.