Tuesday, February 17, 2015

A Little Mystery to Accompany the Moving Stones of the Basin and Range

I'm back from an intense journey through Death Valley National Park and surrounding regions. Much photography and commentary can be expected in the next few weeks, but for today, I'll just lay out a bit of a mystery.
The sliding stones of Racetrack Playa in Death Valley are justly famous, and the mystery of their mode of movement has recently been made clear. But the Racetrack isn't the only place where the stones slide. Bonnie Claire Playa, close to the California-Nevada border, also shows the phenomena. We headed up there on our field studies class. The stones are fascinating, but something else caught my eye while exploring the playa surface.
I don't know what this circle is. It was there by itself, and had no obvious tracks leading to it. Because of its singular nature, I strongly suspect human intervention (SBCC, did you have anything to do with this??). But who knows? If some folks dragged something in a circle, how did they not leave tracks around the edge? Did someone leave a large tire for awhile and retrieve it later?
I even found the circle on Google Earth (below). Again it seems to be all by itself, with no tracks leading to and from.

What do you think is going on here?