Geology Exposed at Chimney Bluffs State Park

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Chimney Bluffs looking east from the shoreline. Photo by Brett Smith.

Some people are drawn to water and some are drawn to dramatic landscapes, Chimney Bluffs State Park on the shore of Lake Ontario has both. Located in Wolcott, New York the park’s namesake bluffs stretch for ½ a mile revealing its ever-changing ancient past.

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Chimney Bluffs looking east. Photo by Brett Smith.

During the last ice age from 2 million years ago until about 10,000 years ago there were a series of glacial advances and retreats that formed the Great Lakes that changed the landscape of the north-central part of the United States in many ways.  One of the clues that glaciers leave behind are called drumlins. We see drumlins as elliptical hills. These hills are blunt on the upglacier end and taper into and elongated tail on the downglacier end, similar in shape to a teardrop. Drumlins form parallel the direction the movement of the ice.  These hills usually form in clusters; the exposed upglacier end of the drumlin at Chimney Bluffs State Park is one of roughly 10,000 drumlins located south and east of Lake Ontario.

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Click on map to enlarge.

The term drumlin refers to the hill’s shape, not its composition. Some drumlins are solid rock and some are composed of glacial till. Till is a mixture of different sized rock fragments and sediment deposited as glacial ice melts. The drumlin at Chimney Bluffs State Park formed when one glacier melted and deposited the till, later a south moving glacier reshaped the material into its present shape.

The north end of the drumlins has been eroded by thousands of year of wave action, wind, rain and snow. As the north end erodes the exposed material is carved into magnificent and ever changing formations. The bluffs are constantly changing source of beauty and danger.

Post by Josh Teeter, OPRHP.

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