Photo Friday: scratch circles

More
Dried dune grasses etch perfect circles in the beach sand. Image: David Marvin

Dried dune grasses etch perfect circles in the beach sand. Image: David Marvin

By Marie Orttenburger

No, they aren’t evidence of an alien visitation–although seeing a wintry beach dotted with perfect, circular indentations might make one think so.

These etchings are the works of dried beach grass. Bent where their stalks meet the sand, the grasses are spun around by strong winds. They draw circles the same way one would with a compass.

David Marvin found a beach dotted with these so-called “scratch circles”  when he visited Little Sable Point, near Silver Lake, Michigan, on December 25.

“Uncharacteristically for us, my wife and I did not have any family commitments on Christmas day this year,” Marvin said. “So we decided to visit some lighthouses along the Lake Michigan coast for a brief day trip.”

Marvin was trying to get a good angle on the lighthouse at Little Sable Point when he saw the circles.

“My attention quickly shifted from the lighthouse to the sand!” he said.

Never having seen such a thing before, Marvin said he was excited to find that the phenomenon has been studied by researchers.

He attributed the circles’ presence to the relatively mild and snow-less winter Michigan has experienced this year.

“Most of the time when I visit the shorelines of the Great Lakes in the winter, snow and ice covers the beach and the beach grass,” Marvin said.  “During the summer I have seen where the longer beach grass leaves make marks in the sand, but this is the first time I have encountered complete circles and arcs in the sand.”

David Marvin’s photo was featured on Universities Space Research Association’s Earth Science Photo of the Day. You can view more of the photos Marvin took that day on his Flickr page.

One thought on “Photo Friday: scratch circles

  1. I discovered one of these on a Lake Ontario beach this winter!!! So nifty!

Leave a Reply

Your email address will not be published. Required fields are marked *