by Mike Hays
You don’t have to travel to Alaska or Norway to see a fjord. Where can you go to see a glacier created, sea-filled canyon? Down by the river. The lower Hudson River has a unique geology since it is both a fjord and, broadly speaking, a drowned river or estuary with tidal inflows.
Between 15,500 and 20,000 years ago, the Hudson River provided an easier groove for the glacier to move further south than it did in the surrounding land. Glacier pushed stones and gravel south forming Long Island. When the glacier retreated north during warming, waters flowed down the Hudson but were blocked from the ocean by the Long Island “dam.” Water from the river flowed through the Sparkill gap at Piermont into the North Jersey lowlands. Eventually, the Long Island dam broke and the Hudson River began to flow into the Atlantic much as it does today.