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Break the Ice at Archbald Pothole State Park
Around ten thousand years ago, something changed on our planet. The two-mile thick sheet of ice that had covered two-thirds of North America for 30,000 years started to melt. The ice, which had reached the northern most regions of Pennsylvania, withdrew its frozen walls, but not before it left its mark at a small location in Lackawanna County named Archbald Pothole State Park.
The discovery of Archbald Pothole nine miles north of Scranton occurred in 1884 by coal miner Patrick Mahon as the miners extended the subterranean mine shaft with explosives. In a massive effort, the miners cleared up to 1,000 tons of rounded stones from a vertical tunnel that reached almost forty feet to the open air above. Not only had they found an uncommon and massive ventilation shaft for the mine, they had unveiled a natural landmark that had been preserved by nature for almost 15,000 years.
As the world’s largest pothole, with an elliptical diameter of 42 feet by 24 feet and a depth of 38 feet, Archbald provided scientists with evidence of the Wisconsin Glacial Period. It also stands as a marker for the nearby glacial terminus, a beacon to show us how far the legendary ice sheet traveled during its lifespan before it began to rapidly melt and retreat. What makes the Archbald Pothole even more phenomenal is its ancient formation. With surface streams and river flowing across the glacier as it melted, a crevasse in the ice created a waterfall that produced enough force to begin grinding up the bedrock below. The Archbald Pothole cut through sandstone, shale, and, finally, anthracite coal to create the geologic wonder we see today. In total, the pothole could hold about 140,000 gallons of water, equivalent to seven times the amount held in your average backyard swimming pool.
Archbald Pothole State Park closes the third Saturday of November and opens the second Friday of April 2018. At the park, a small loop trail takes you on an old coal mine trail that passes rock ledges and winds through a forest. If you’re comfortable with heights or seeking a rush, you can also stand over the pothole on the ledge and peer down into the depths.
Visit the Department of Conservation and Natural Resources website for more information on Archbald Pothole State Park and history of the glaciers that moved into Pennsylvania.
Archbald Pothole State Park
1839 Abington Road
North Abington Township, PA 18414
Brandon Sherbo, Guest Blogger