Hocking Hills' Ice-age Quest

Rylan Lee
Old Man's Cave in Hocking Hills

Old Man's Cave, a natural wonder for visitors, has become the focal point of frustration for Ohio geologists who still know little about the formation of Hocking Hills State Park. Thus, experts from the Ohio Geological Survey have begun a project to collect samples of sediment untouched by the sun for more than 100,000 years that they hope will reveal more about the park's origins.

Using a technique called OSL, or optically stimulated luminescence, which measures the last time a sample of quartz sediment was exposed to sunlight, the team will be able to more precisely date the park. The challenge, however, will be collecting sediment without exposing it to present-day sunlight, which would “reset the quartz clock,” says Tom Serenko, Ohio's state geologist.

The experts had originally planned to collect samples of sand from deep within the park's caves. But after an initial survey of cave sites found the sediment insufficiently deep, they are now switching gears. In an unexpected twist, the team did find potentially viable lake bed samples. These samples will help geologists understand how the park's valleys were formed. Little about the land's origin is known, aside from the presumed effects of a massive ice sheet, which drifted into Ohio during the last ice age.

While turning their focus to the lake bed was a surprise for the geologists, Serenko remains optimistic. “We know so little about the area that any information that we can get is going to be useful for understanding what actually took place.”

Want to getColumbus Monthly in your inbox? Sign up for oure-newsletter.