Wanderlust World Wanderlust World Niagara Falls owes its existence to the Wisconsin glaciation (~10,000 years ago). A massive ice sheet carved the Great Lakes basins and the Niagara River corridor. As the glacier retreated, meltwater established drainage from the upper Great Lakes (Superior, Michigan, Huron, Erie) through Lake Ontario to the St. Lawrence River and Atlantic.
The falls' location is controlled by a resistant caprock layer—the Lockport Dolomite (Silurian age). This hard, magnesium-rich limestone overlies softer Rochester Shale. The river erodes the shale rapidly, undercutting the dolomite, which then collapses in blocks. This process maintains the falls' vertical face while causing upstream retreat (~1 foot/year historically, now slowed by water diversion).
Near the falls, the Niagara River makes a 90-degree turn due to the differential erosion resistance of the Lockport Dolomite formation. This geological "knee" creates the dramatic plunge points: Horseshoe Falls (Canadian side), American Falls, and Bridal Veil Falls.
The falls have retreated ~11 km (7 miles) from the Niagara Escarpment at Queenston/Lewiston to their current position. Hydroelectric diversion (50-75% flow reduction) has significantly slowed erosion, preserving this UNESCO World Heritage Site for future generations.