Sand may still be dropping through nature’s hourglass atop Lake Michigan’s dunes that stretch from Indiana to Muskegon, an MSU researcher determined.

Associate geography Professor Alan Arbogast presented his research, which disputes claims that the dunes stopped forming 5,000 years ago, to the Geological Society of America last week in Boston.

Arbogast said the research may cause those who make attempts to protect the dunes or use them for recreation or sand mining to re-evaluate their stances.

“These are pretty high-profile landscapes in the state,” Arbogast said. “We discovered that there is a longer history and different history with the lake than originally thought.”

Arbogast said the dunes likely started to grow 5,000 years ago but have grown periodically in significant amounts since that time. He said the dunes have grown 30 feet in the last 500 years.

They now stand about 90 to 100 feet tall on average.

“What seems to happen is when the lake is in its highest stage and strong storms hit the beach and the base (becomes) heavily eroded