Difference between revisions of "Galatia Channel:Similar Channels Affecting Other Coal Seams"

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(Danville Coal)
(Murphysboro Coal and Oraville Channel)
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==Murphysboro Coal and Oraville Channel==
 
==Murphysboro Coal and Oraville Channel==
The Murphysboro Coal, in the upper Tradewater Formation, presents some similarities to the Colchester, Springfield, Herrin, and Danville Coals in that thick, low-sulfur coal is associated with a gray shale “wedge” and a contemporaneous channel. However, the Murphysboro is highly lenticular and has been less thoroughly studied than the other examples, so the relationship of coal to gray shale and the channel is not completely understood.
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[[Galatia Channel:Murphysboro Coal and Oraville Channel|Murphysboro Coal and Oraville Channel]]
 
 
Jacobson (1983) documented that thick, low-sulfur Murphysboro Coal in southwestern Illinois flanks a feature that he named the Oraville channel (Figures [[:File:C605-Figure-39.jpg|39]] and [[:File:C605-Figure-47.jpg|47]]). In fact, coal of mineable thickness (up to 8.2 ft [2.5 m]) is confined to a small area near the channel. Sulfur content is low to moderate (1 to 2.5%) near the channel where thick, nonmarine gray mudstone (unnamed) overlies the coal. Elsewhere, the coal is topped by marine black shale and limestone, and its sulfur content is greater than 3% (Jacobson 1983). Away from the Oraville channel, the Murphysboro has a highly patchy distribution (Treworgy and Bargh 1984). Only small, isolated areas of thick coal are known. Little significant mining has taken place away from the channel.
 
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<li style="display: inline-block;">[[File:C605-Figure-39.jpg|500px|{{File:C605-Figure-39.jpg}}|thumb]]</li>
 
<li style="display: inline-block;">[[File:C605-Figure-47.jpg|500px|{{File:C605-Figure-47.jpg}}|thumb]]</li>
 
<li style="display: inline-block;">[[File:C605-Figure-48.jpg|500px|{{File:C605-Figure-48.jpg}}|thumb]]</li>
 
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The Murphysboro undergoes dramatic splitting near the Oraville channel margins, where underclay is absent or weakly developed ([[:File:C605-Figure-48.jpg|Figure 48]]). Upright lycopsid tree stumps are common above the lower coal bench. The gray mudstone exhibits tidal rhythmites and bears a prolific, well-preserved flora dominated by Macroneuropteris scheuchzeri, a plant believed to have been tolerant of coastal, perhaps brackish-water, conditions (Falcon-Lang 2009). The Oraville channel follows the downthrown side of a monocline that was active during deposition of the Murphysboro Coal (Nelson et al. 2011).
 
 
 
Ostensibly, the Oraville is another fluvial channel that became an estuary, like the Galatia and Walshville channels. However, nothing is known of the presumed fluvial “precursor” channel, and the nature of “splitting” coal is poorly understood. Further study of the Murphysboro is required to integrate this unit into a general model.
 
  
 
{{Galatia Channel Page}}
 
{{Galatia Channel Page}}

Revision as of 14:58, 14 July 2020

Similar Channels Affecting Other Coal Seams

Several well-documented paleochannels in the Illinois Basin existed contemporaneously with peat deposits older and younger than the Springfield (Figure 39). The Galatia channel provides an apt model for comparison.

  • Figure 39 Map of the Illinois Basin showing channels and gray shale wedges affecting the Murphysboro, Colchester, Herrin, Baker, and Danville Coals.

Colchester Coal and Francis Creek Shale

Colchester Coal and Francis Creek Shale

Herrin Coal, Energy Shale, and Walshville Channel

Herrin Coal, Energy Shale, and Walshville Channel

Baker Coal and Winslow-Henderson Channel

Baker Coal and Winslow-Henderson Channel

Danville Coal

Danville Coal

Murphysboro Coal and Oraville Channel

Murphysboro Coal and Oraville Channel


Primary Source

W. John Nelson, Scott D. Elrick, William A. DiMichele, and Philip R. Ames xxxx, Evolution of a Peat-Contemporaneous Channel: The Galatia Channel, Middle Pennsylvanian, of the Illinois Basin FINISH CITATION

References