4th December – Sharon Conglomerate

Sharon Conglomerate in the Gorge Metropark, Cuyahoga Falls

Chris: Finding outcrops in Northeast Ohio can be a little challenging at times, thanks to all the glacial till dumped onto the landscape during the last deglaciation. Near Kent, your best bet is where the Cuyahoga River has cut down through the till to expose the rocks underneath, as is the case at the Gorge Metropark in nearby Cuyahoga Falls, which is a nice place to take our new Geology Majors for a quick morning field trip. The first unit they see is shown here: the Late Carboniferous (yes, they call it Pennsylvanian here, but they also cling to Imperial units and the Fahrenheit scale) Sharon Conglomerate, which forms the high sides of the gorge the park is named for. At least in this location, this ‘conglomerate’ is actually more a very pure quartz sandstone with conglomerate lenses, full of lovely rounded pebbles indicating significant fluvial transport. There’s also a bed with well-developed cross-bedding on the right hand side of this photo. This is a good example of being able to build up a picture of a depositional environment (in this case, a braided river system by studying lithology, grain size, and sedimentary structures.

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