This is Mazon Monday post #90. What's your favorite Mazon Creek fossil? Tell us at email:[email protected].
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For December 2021, the presentation by Scott Elrick provided context for the Danville, IL spoil pile fossils. Scott also discussed coal formation in Illinois during the Pennsylvanian. Additionally, he mentioned where the Colchester #2 Coal, associated with Mazon Creek, fits into the paleo-environment of the Pennsylvanian.
The speaker at our December 3, 2021 meeting was Scott Elrick, Head of the Coal, Bedrock and Industrial Minerals Section of ISGS. The topic of his talk via Zoom was paleoecology of the Herrin Coal roof shales including depositional environment and climate. This talk added context to the fossil flora found at the Danville shale pile.
A story about Scott and the discovery of a large underground coal forest in the Smithsonian Magazine from 2009.
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Finding a fossil in a coal mine is no big deal. Coal deposits, after all, are petrified peat swamps, and peat is made from decaying plants, which leave their imprints in mud and clay as it hardens into shale stone.
But it was a different thing entirely when John Nelson and Scott Elrick, geologists with the Illinois State Geological Survey, examined the Riola and Vermilion Grove coal mines in eastern Illinois. Etched into ceilings of the mine shafts is the largest intact fossil forest ever seen—at least four square miles of tropical wilderness preserved 307 million years ago. That's when an earthquake suddenly lowered the swamp 15 to 30 feet and mud and sand rushed in, covering everything with sediment and killing trees and other plants. "It must have happened in a matter of weeks," says Elrick. "What we see here is the death of a peat swamp, a moment in geologic time frozen by an accident of nature."
To see this little-known wonder, I joined Nelson and Elrick at the Vermilion Grove site, a working mine operated by St. Louis-based Peabody Energy and closed to the public. I donned a hard hat, a light, gloves and steel-toed boots. I received an oxygen bottle and a safety lecture. In case of emergency—poison gas, fire or an explosion—follow the red lights to find the way out of the mine, safety manager Mike Middlemas counseled. We could encounter "thick black smoke, and you won't be able to see anything in front of you." He said to use the lifeline running along the ceiling, a slender rope threaded through wooden cones, like floats in a swimming pool.
