Friday Field Foto #17: Clast imbrication

Today's field photograph comes from the Valley of Fire region in Nevada. A few years ago we organized a student-led field trip to this area to check out some of the fantastic geology on display.

This particular photo shows nice clast imbrication in a Cretaceous alluvial fan sequence. Note the three clasts just below the pencil stacked on each other showing the paleocurrent direction to the right. If you go hike around on a modern alluvial fan or stream with cobbles in it, you will likely find small piles of imbricated clasts just like this.